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Simple Summary: The Taklamakan Desert is a harsh and extreme environment, yet its microorganisms hold untapped potential to benefit agriculture and medicine. In this study, we discovered a new microbial species, Streptomyces xanthus, isolated from desert soil. Genomic and metabolomic analyses revealed that this microorganism produces several unknown compounds. We isolated one novel and four known compounds from this strain, all reported for the first time in desert environments. Notably, one known compound, thiolutin, showed strong activity against five local plant pathogenic fungi, with a production yield of 270 mg/L. These findings highlight the desert as a reservoir of new microbial species, holding great potential for discovering important bioactive compounds. The Taklamakan Desert is an extreme environment supporting a unique and diverse microbial community with significant potential for exploration. Strain TRM70308T, isolated from desert soil, shares 98.43% 16S rRNA gene sequence similarity with Streptomyces alkaliterrae OF1T. Polyphasic taxonomy confirmed TRM70308T as a novel species, named Streptomyces xanthus. Genomic analysis revealed that only one of the strain's 25 biosynthetic gene clusters (BGCs) formed a cluster of gene families (CGFs) within the MIBiG database, emphasizing its genomics uniqueness. LC-MS/MS and Feature-Based Molecular Networking (FBMN) identified 33 metabolites across various categories, including alkaloids, saponins, benzoic acids, and benzofurans, most of which remain uncharacterized. Further chemical investigation led to the isolation of one novel compound, aconicarpyrazine C, and four known compounds: thiolutin, dibutyl phthalate, bis(2-ethylhexyl) phthalate, and N-acetyltryptamine. Thiolutin exhibited strong activity against five local fungal pathogens that cause plant diseases, with a production yield of 270 mg/L. These results establish a foundation for pilot-scale thiolutin production and its potential development as an antifungal agent for agricultural applications. Our findings highlight deserts as a valuable source of novel actinomycetes and bioactive natural products with immense potential for future research and development. [ABSTRACT FROM AUTHOR]

Abstract The urgent need for sustainable agriculture has intensified the search for environmentally friendly alternatives to chemical herbicides. This study investigates the herbicidal potential of siderophores produced by Amycolatopsis lurida strain 407, focusing on its effects on the growth of ryegrass and redroot weeds. Strain 407 exhibited two distinct colony morphologies—red and white—when cultured under varying environmental conditions. The cell-free culture filtrate (CFCF) from both colony types significantly inhibited the growth of ryegrass and redroot. The concentration of siderophore produced in the iron-deficient medium was measured to be 613.4 ppm for 407 red and 388.5 ppm for 407 white, which indicates significant iron chelating activity. This study also showed a direct relationship between the presence of siderophore in plant culture medium and reduced growth. Also, analysis of fractions of the aqueous phase resulting from column chromatography revealed that all fractions from the 407 red reduced ryegrass shoot length by up to 45% and root length by 83–86%, while redroot seedling length decreased by up to 36%. Fractions from 407 white completely inhibited germination or reduced ryegrass root length by up to 94% and redroot seedling length by 52%. Fractions F4 W to F7 W and F2 R to F8 R, which showed iron chelating activity were most effective in reducing plant growth, suggesting that there are metabolites, alone or in company with siderophores, synergistically do herbicidal activity. The innovative application of siderophores as bioherbicide presents a promising environmentally friendly alternative to chemical herbicides.

Two previously undescribed compounds, including one phenylpropanoid derivative, BC129–2 (1) and one p -menthane analogue, cis - p -menthane-7,8-diol (2), were isolated from the EtOAc-soluble fraction of the culture broth of an actinomycete Streptomyces sp. BC129–2. The structures of all isolates were elucidated on the basis of extensive analyses of spectroscopic data and comparison with literature data. Their antifungal activity was also evaluated. Our results showed that 2 constituents (compounds 1 & 2) possessed mild antifungal activity against Fusarium sp. LC8, Neopestalotiopsis sp. BCRC 35002, and Colletotrichum gloeosporioides BCRC 35178. It is worth mentioning that the chemical composition of the type strain Streptomyces sp. BC129–2 has never been studied. [Display omitted] • One benzenoid, BC129–2 (1) and one p -menthane analogue were isolated from Streptomyces BC129–2. • 1 demonstrated the highest antifungal activity against 3 test organisms. • 2 showed different sensitivities in inhibiting the growth of test organisms. • These data suggest the potential use of compound 1 as a biocontrol agent. [ABSTRACT FROM AUTHOR]

One previously undescribed imide analogue M7 (1), along with three known ones, methyl palmitate (2), methyl linoleate (3) and ergosterol peroxide (4), were isolated from the EtOAc extract of the culture broth of an actinobacteria Streptomyces sp. M7. The structure was elucidated on the basis of extensive analyses of spectroscopic data and comparison with literature data. [ABSTRACT FROM AUTHOR]

Abstract Background Natural products play a key role as potential sources of biologically active substances for the discovery of new drugs. This study aimed to identify secondary metabolites from actinomycete library extracts that are potent against the asexual stages of Plasmodium falciparum (P. falciparum). Methods Secondary metabolites from actinomycete library extracts were isolated from culture supernatants by ethyl acetate extraction. Comprehensive screening was performed to identify novel antimalarial compounds from the actinomycete library extracts (n = 28). The antimalarial activity was initially evaluated in vitro against chloroquine/mefloquine-sensitive (3D7) and-resistant (Dd2) lines of P. falciparum. The cytotoxicity was then evaluated in primary adult mouse brain (AMB) cells. Results Out of the 28 actinomycete extracts, 17 showed parasite growth inhibition > 50% at a concentration of 50 µg/mL, nine were identified with an IC50 value

Objective Melon charcoal rot is one of the most important diseases that significantly reduces the yield of melon (Cucumis melo L.). The main objectives of this study were: isolation of actinomycetes from the rhizospheric soil of different melon cultivation regions located in the Kerman and Sistan and Baluchestan provinces of Iran; investigating the antagonistic effects of actinomycetes against melon black stem or charcoal rot disease; evaluation of siderophore production by isolates in vitro; identification of potential isolate by PCR, and investigating their biocontrol efficacy against Macrophomina phaseolina in melon under greenhouse condition. Materials and methods Eighty actinomycete isolates were isolated from the soil of selected different melon cultivation areas and their antifungal activity against Macrophomina phaseolina was investigated. Potential isolates were evaluated for biological activities. Moreover, the efficacy of selected actinobacteria in order to biocontrol charcoal rot disease was investigated under greenhouse condition. Results Three actinomycete isolates (R1.6, R5.52 and R5.56) were revealed the highest inhibition zone size against Macrophomina phaseolina and selected for further investigations. All three isolates were able to colonize melon roots, produce extracellular enzymes and control disease in the greenhouse. The actinomycete isolate R5.56 was identified by sequence analysis of small ribosomal RNA subunit (16S rRNA) and based on the results this isolate had the highest similarity (98%) with Streptomyces species. Conclusions Biological control of plant pathogens, unlike the application of chemical pesticides, does not work quickly, but in successful cases, has more long-lasting effects compare to chemical pesticides. Biological control should be mentioned as a key component of the integrated pests and plant diseases management system approaches to minimize the environmental side effects and risks as the consequences of over usage of chemicals. This study is a prelude to further studies such as the use of these antagonists against Macrophomina phaseolina in the field, which must be done for at least three years. [ABSTRACT FROM AUTHOR]

In this study, an Actinomycetota Streptomyces mediolani strain CF51DZ was isolated from a beetle Protaetia morio collected in a cork oak forest in northeast Algeria, to extract, purify and characterize the antibacterial compound. The strain was isolated in specific ISP culture media, identified via morphological, biochemical, physiological and molecular characteristics and then studied its antibacterial activities against pathogenic bacteria using the well diffusion technique. The extraction, purification and characterization of the bioactive compound was carried out using chromatographic and spectroscopic methods. Morphological, physiological, and biochemical properties, as well as the 16S ribosomal DNA sequence of the strain, were found close to those of Streptomyces mediolani. The isolated strain produced an active compound having potent antibacterial properties against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. This compound was isolated and purified with thin layer chromatography and high-performance liquid chromatography, and chemically identified by mass spectroscopy and NMR spectroscopy. In addition, the chemical structure elucidation of the antibacterial metabolite by APCI-MS analysis revealed a peak at m/z 375 [M+H]+, a molecular formula of C19H18O8. This compound was identified as methyl rosarinate: 3-(3,4-dihydroxyphenyl)-1-methoxy-1-oxopropan-2-yl (E)-3-(3,4-dihydroxyphenyl)acrylate based on the IUPAC nomenclature. Moreover, the antibacterial agent was purified from Streptomyces mediolani strain CF51DZ that was for the first time, in Algeria, isolated from the beetle Protaetia morio. This supports further characterization of this promising chemical to ensure the best use for antibacterial applications.

Secondary metabolites produced by actinomycete strains undoubtedly have great potential for use in applied research areas such as drug discovery. However, it is becoming difficult to obtain novel compounds because of repeated isolation around the world. Therefore, a new strategy for discovering novel secondary metabolites is needed. Many researchers believe that actinomycetes have as yet unanalyzed secondary metabolic activities, and the associated undiscovered secondary metabolite biosynthesis genes are called “silent” genes. This review outlines several approaches to further activate the metabolic potential of actinomycetes.

A tremendous increase in the green synthesis of metallic nanoparticles has been noticed in the last decades, which is due to their unique properties at the nano dimension. The present research work deals with synthesis mediated by the actinomycete Streptomyces tendae of silver nanoparticles (AgNPs), isolated from Little and Greater Rann of Kutch, India. The confirmation of the formation of AgNPs by the actinomycetes was carried out by using a UV-Vis spectrophotometer where an absorbance peak was obtained at 420 nm. The X-ray diffraction pattern demonstrated five characteristic diffraction peaks indexed at the lattice plane (111), (200), (231), (222), and (220). Fourier transform infrared showed typical bands at 531 to 1635, 2111, and 3328 cm−1. Scanning electron microscopy shows that the spherical-shaped AgNPs particles have diameters in the range of 40 to 90 nm. The particle size analysis displayed the mean particle size of AgNPs in aqueous medium, which was about 55 nm (±27 nm), bearing a negative charge on their surfaces. The potential of the S. tendae-mediated synthesized AgNPs was evaluated for their antimicrobial, anti-methicillin-resistant Staphylococcus aureus (MRSA), anti-biofilm, and anti-oxidant activity. The maximum inhibitory effect was observed against Pseudomonas aeruginosa at (8 µg/mL), followed by Escherichia coli and Aspergillus niger at (32 µg/mL), and against Candida albicans (64 µg/mL), whereas Bacillus subtilis (128 µg/mL) and Staphylococcus aureus (256 µg/mL) were much less sensitive to AgNPs. The biosynthesized AgNPs displayed activity against MRSA, and the free radical scavenging activity was observed with an increase in the dosage of AgNPs from 25 to 200 µg/mL. AgNPs in combination with ampicillin displayed inhibition of the development of biofilm in Pseudomonas aeruginosa and Streptococcus pneumoniae at 98% and 83%, respectively. AgNPs were also successfully coated on the surface of cotton to prepare antimicrobial surgical cotton, which demonstrated inhibitory action against Bacillus subtilis (15 mm) and Escherichia coli (12 mm). The present research integrates microbiology, nanotechnology, and biomedical science to formulate environmentally friendly antimicrobial materials using halotolerant actinomycetes, evolving green nanotechnology in the biomedical field. Moreover, this study broadens the understanding of halotolerant actinomycetes and their potential and opens possibilities for formulating new antimicrobial products and therapies. [ABSTRACT FROM AUTHOR]

In this study, an Actinomycetota Streptomyces mediolani strain CF51DZ was isolated from a beetle Protaetia morio collected in a cork oak forest in northeast Algeria, to extract, purify and characterize the antibacterial compound. The strain was isolated in specific ISP culture media, identified via morphological, biochemical, physiological and molecular characteristics and then studied its antibacterial activities against pathogenic bacteria using the well diffusion technique. The extraction, purification and characterization of the bioactive compound was carried out using chromatographic and spectroscopic methods. Morphological, physiological, and biochemical properties, as well as the 16S ribosomal DNA sequence of the strain, were found close to those of Streptomyces mediolani. The isolated strain produced an active compound having potent antibacterial properties against Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus. This compound was isolated and purified with thin layer chromatography and high-performance liquid chromatography, and chemically identified by mass spectroscopy and NMR spectroscopy. In addition, the chemical structure elucidation of the antibacterial metabolite by APCI-MS analysis revealed a peak at m/z 375 [M+H]+, a molecular formula of C19H18O8 . This compound was identified as methyl rosarinate: 3-(3,4-dihydroxyphenyl)-1-methoxy1-oxopropan-2-yl (E)-3-(3,4-dihydroxyphenyl)acrylate based on the IUPAC nomenclature. Moreover, the antibacterial agent was purified from Streptomyces mediolani strain CF51DZ that was for the first time, in Algeria, isolated from the beetle Protaetia morio. This supports further characterization of this promising chemical to ensure the best use for antibacterial applications. [ABSTRACT FROM AUTHOR]

Bioprospecting actinobacterial secondary metabolism from untapped marine sources may lead to the discovery of biotechnologically-relevant compounds. While studying the diversity and bioactive potential of Actinomycetota associated with Codium tomentosum, a green seaweed collected in the northern Portuguese cost, strain CT-F61, identified as Streptomyces violaceoruber, was isolated. Its extracts displayed a strong anticancer activity on breast carcinoma T-47D and colorectal carcinoma HCT116 cells, being effective as well against a panel of human and fish pathogenic bacteria. Following a bioactivity-guided isolation pipeline, a new analogue of the red-pigmented family of the antibiotics prodigiosins, decylprodigiosin (1), was identified and chemically characterized. Despite this family of natural products being well-known for a long time, we report a new analogue and the first evidence for prodigiosins being produced by a seaweed-associated actinomycete. [ABSTRACT FROM AUTHOR]

Aedes aegypti Linn. (Diptera: Culicidae) is one the most common vectors of disease-causing arboviruses such as dengue and chikungunya. The lack of vaccines for these diseases coupled with the current problem of increasing insecticide resistance intensifies the need to find novel and efficient ways of controlling the vector population. Hence, this paper aims to investigate the biological activity of Philippine Streptomyces isolates against Ae. aegypti as potential biological agents to manage the population of these mosquitoes. Prior to the testing of the biological activity, eight actinomycete isolates were identified based on morphological, cultural, and molecular characterizations using their 16S rRNA sequences. BLASTn results of the generated nucleotide sequences showed 98-100% similarity with different Streptomyces species and were assigned with the GenBank accession numbers MZ317443-MZ317450. Among the eight isolates, a CDC bottle bioassay of the extracted metabolites against 3 to 5-day old female Aedes aegypti adults revealed that CGS C13 (92.68%), DK 5-10 (85.53%), and CGS B11 (81.91%) showed the highest adulticidal activity statistically comparable to the positive control (abamectin). LC50 determination through dose-response bioassays showed that CGS B11 had the highest activity (2.838 ppm), followed by DK 5-10 (6.083 ppm) and CGS C13 (519.281 ppm). This is the first report on the insecticidal activity of these Streptomyces species against Ae. aegypti. [ABSTRACT FROM AUTHOR]

With the rise in antimicrobial resistance, there is an urgent need for new classes of antibiotic with which to treat infectious disease. Marinomycin, a polyene antibiotic from a marine microbe, has been shown capable of killing methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus faecium (VREF), as well as having promising activity against melanoma. An attractive solution to the photoprotection of this antibiotic has been demonstrated. Here, we report the identification and analysis of the marinomycin biosynthetic gene cluster (BGC), and the biosynthetic assembly of the macrolide. The marinomycin BGC presents a challenge in heterologous expression due to its large size and high GC content, rendering the cluster prone to rearrangement. We demonstrate the transformation of Streptomyces lividans using a construct containing the cluster, and the heterologous expression of the encoded biosynthetic machinery and production of marinomycin B. [ABSTRACT FROM AUTHOR]

In recent years, researchers have turned their attention to the co-cultivation of microalgae and plants as a means to enhance the growth of hydroponically cultivated plants while concurrently producing microalgal biomass. However, the techniques used require precise calibration based on plant growth responses and their interactions with the environment and cultivation conditions. This study initially focused on examining the impact of hydroponic nutrient concentrations on the growth of the microalga Chlorella sp. AARL G049. The findings revealed that hydroponic nutrient solutions with electrical conductivities (EC) of 450 µS/cm and 900 µS/cm elicited a positive response in microalgae growth, resulting in high-quality biomass characterized by an elevated lipid content and favorable properties for renewable biodiesel. The biomass also exhibited high levels of polyunsaturated fatty acids (PUFAs), indicating excellent nutritional indices. The microalgae culture and microalgae-free culture, along with inoculation-free lettuce (Lactuca sativa L. var. longifolia) and lettuce that was inoculated with plant growth actinobacteria, specifically the actinomycete Streptomyces thermocarboxydus S3, were subsequently integrated into a hydroponic deep-water culture system. The results indicated that several growth parameters of lettuce cultivated in treatments incorporating microalgae experienced a reduction of approximately 50% compared to treatments without microalgae, and lowering EC levels in the nutrient solution from 900 µS/cm to 450 µS/cm resulted in a similar approximately 50% reduction in lettuce growth. Nevertheless, the adverse impacts of microalgae and nutrient stress were alleviated through the inoculation with actinomycetes. Even though the co-cultivation system leads to reduced lettuce growth, the system enables the production of high-value microalgal biomass with exceptional biodiesel fuel properties, including superior oxidative stability (>13 h), a commendable cetane number (>62), and a high heating value (>40 MJ/kg). This biomass, with its potential as a renewable biodiesel feedstock, has the capacity to augment the overall profitability of the process. Hence, the co-cultivation of microalgae and actinomycete-inoculated lettuce appears to be a viable approach not only for hydroponic lettuce cultivation but also for the generation of microalgal biomass with potential applications in renewable energy. [ABSTRACT FROM AUTHOR]

Bioprospecting actinobacterial secondary metabolism from untapped marine sources may lead to the discovery of biotechnologically-relevant compounds. While studying the diversity and bioactive potential of Actinomycetota associated with Codium tomentosum, a green seaweed collected in the northern Portuguese cost, strain CT-F61, identified as Streptomyces violaceoruber, was isolated. Its extracts displayed a strong anticancer activity on breast carcinoma T-47D and colorectal carcinoma HCT116 cells, being effective as well against a panel of human and fish pathogenic bacteria. Following a bioactivity-guided isolation pipeline, a new analogue of the red-pigmented family of the antibiotics prodigiosins, decylprodigiosin (1), was identified and chemically characterized. Despite this family of natural products being well-known for a long time, we report a new analogue and the first evidence for prodigiosins being produced by a seaweed-associated actinomycete.

Individuals with COVID-19 are prone to a variety of infections due to immune dysregulation. The present report presents a case of actinomycotic infection in the maxillary bone and sinus region in a patient with a history of COVID-19. This case report highlights the importance of considering bacterial infections including actinomycosis when encountering destructive lesions resembling more prevalent fungal infections due to different therapeutic medication protocols. In addition, a literature review of the existing reports of similar post-COVID-19 actinomycotic infection is presented. [ABSTRACT FROM AUTHOR]

Oilseed rape (Brassica napus L.) is highly susceptible to infection from the soilborne pathogen Plasmodiophora brassicae Woronin that causes clubroot disease and deleteriously affects production throughout the world. In this study, biological control resources were explored by isolating 237 strains of bacteria from fields of oilseed rape using the gradient dilution coating method. A strain with strong antagonistic ability was screened using a plate confrontation test and designated X216. It was identified as Streptomyces melanosporofaciens owing to its morphological characteristics and 16S rRNA gene sequence. This study also examined the lethality of strain X216 to the resting spores of P. brassicae, its influence on infection in root hairs, and its ability to control clubroot on oilseed rape. The corrected lethality rate on resting spores after strain X216 had been used for 14  days was 56.59%  ±  1.97%, which was significantly higher than the use of 75% of the fungicides chlorothalonil WP and 20% Fluazinam SC. Significantly fewer root hairs were infected after this treatment. A pot test showed that X216 was 62.14% effective at controlling the disease, which was not significantly different from that of the fungicide 100  g  L-1 cyazofamid SC diluted 1,000-fold but significantly higher than those of 75% chlorothalonil and 50% carbendazim WP. Strain X216 controlled 43.16% of the incidence of clubroot in the field, which could significantly reduce the disease index of oilseed rape clubroot. Therefore, strain X216 is promising to study for the biological control of oilseed rape clubroot. [ABSTRACT FROM AUTHOR]

Quorum-sensing (QS) is involved in numerous physiological processes in bacteria, such as biofilm formation, sporulation, and virulence formation. Therefore, the search for new quorum-sensing inhibitors (QSI) is a promising strategy that opens up a new perspective for controlling QS-mediated bacterial pathogens. To explore new QSIs, a strain named Streptomyces sp. D67 with QS inhibitory activity was isolated from the soil of the arid zone around the Kumutag Desert in Xinjiang. Phylogenetic analyses demonstrated that strain D67 shared the highest similarity with Streptomyces ardesiacus NBRC 15402T (98.39%), which indicated it represented a potential novel species in the Streptomyces genus. The fermentation crude extracts of strain D67 can effectively reduce the violacein production produced by Chromobacterium violaceum CV026 and the swarming and swimming abilities of Pseudomonas aeruginosa. It also has significant inhibitory activity on the production of virulence factors such as biofilm, pyocyanin, and rhamnolipids of P. aeruginosa in a significant concentration-dependent manner, but not on protease activity. A total of 618 compounds were identified from the fermentation crude extracts of strain D67 by LC-MS, and 19 compounds with significant QS inhibitory activity were observed. Overall, the strain with QS inhibitory activity was screened from Kumutag Desert in Xinjiang for the first time, which provided a basis for further research and development of new QSI. [ABSTRACT FROM AUTHOR]

Objective: Forensic microbiology is the developing field of forensic science. Forensic microbiologist can use trace evidence to match people to crime scenes, to investigate bioterrorism incidents, and to determine cause and time of death. In recent years, important studies on the environmental microbiota have been carried out. These studies can be associated with many legally valuable data as well as being related to the microbiota of environmental events. Actinobacteria are gram-positive micelle bacteria with enormous diversity, common in soil, and have high economic value. So far 47 families and 711 species of Actinobacteria were isolated and identified in variety of habitats. Increasing forensic studies in recent years show that microbial profiles can be used as evidence. Methods: In this study, actinobacteria were isolated from forest soil samples exposed to eight different blood groups for two weeks and control group. Genomic DNA isolation from colonies selected by considering comparative colony morphology, PCR amplification targetted 16S rRNA and sequence analysis were carried. Results: A total of five Actinobacteria type bacteria (three Micromonospora sp., one is Streptomyces sp., and one Actinomadura sp.) were obtained from the soil samples mixed with the B Rh (+) blood group in the 7th day. No Actinobacteria growth was observed neither in the control group nor in the soils to which other blood groups were added. According to the p-distance values of all isolates, they were determined as subspecies rather than a new species. Conclusion: This is a preliminary study to identify bacterial communities that may be present and differ in soil exposed to blood. The inability to isolate Actinobacteria from most of the soil samples may be due to the chemical or enzymatical properties of the bloods that can degrade the bacterial spores. In the further studies, different media and genomic techniques should be tried in different types of soils. [ABSTRACT FROM AUTHOR]

A microbial fuel cell (MFC), a novel technology, is a biochemical catalyzer system that can convert the chemical energy of materials to bioelectric energy. This system can serve as a unique device for the treatment of wastewater. Based on this knowledge, we decided to study the bioenergy production ability of Actinomycete and microbial isolates in industrial glass factory wastewater as the decomposers of organic materials in this wastewater and the generation of Voltage and current in two batches and fed-batch conditions. At the most favorable condition maximum of 1.08 V (current 3.66 mA and power density 2.88 mW/m2), 81.2% chemical oxygen demand was obtained for a fed-batch system. Also, the outcomes of MFC’s essential parameters, for example, pH and TDS, were studied before and after the performance of MFC. The results showed a significant decrease after the operation of the MFC. To realize which Actinomycete were the most powerful bioelectric microorganism, the growth curve and electricity performance of three kinds of Actinomycete was selected. Results showed that the C2 would be more potent because its Voltage of 0.224 V and current of 1.187 mA possessed by it would result in an excellent power density of 141.42 mW/m2.

An actinomycete, designated strain HSS6-12T, was isolated from hot spring sediment collected from Ranong province, Thailand. The strain showed taxonomic characteristics consistent with those of members of the genus Micromonospora. HSS6-12T produced a single spore directly on the substrate mycelium, and no aerial mycelium was detected. The isomer of diamino acid presented in cell wall peptidoglycan was meso-diaminopimelic acid. Arabinose, xylose, glucose, and ribose were detected in whole-cell hydrolysates. MK-10(H4), MK-9(H4), and MK-10(H6) were major menaquinones. Major cellular fatty acids were iso-C16:0, iso-C15:0, and iso-C17:0. Phospholipid profile was composed of diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositolmannosides. 16S rRNA gene analysis revealed that HSS6-12T shared the highest 16S rRNA gene sequence similarity with Micromonospora inositola DSM 43819T (99.3%). In contrast, the genome analysis showed that HSS6-12T formed a tight taxonomic position in a phylogenomic tree with Micromonospora endolithica DSM 44398T. Moreover, the average nucleotide identity-blast, the digital DNA-DNA hybridization, and the average amino acid identity values between HSS6-12T and M. inositola DSM 43819T and M. endolithica DSM 44398T were 83.1–84.0%, 27.5–28.7%, and 80.4–82.2%, respectively, indicating that HSS6-12T was different species with both closely related Micromonospora-type strains. In addition, HSS6-12T could be discriminated from its closely related type strains by many physiological and biochemical characteristics. Thus, HSS6-12T could be considered a novel species of the genus Micromonospora, and the name Micromonospora thermarum is proposed for the strain. The type strain is HSS6-12T (= BCC 41915T = JCM 17127T). [ABSTRACT FROM AUTHOR]

Herbicidal active metabolites obtained from actinomycetes provide valuable sources in the search for new candidates. They might be striking alternatives to synthetic herbicides. In the present study, actinobacteria strains were isolated from soil samples and their herbicidal activities were screened. In the screening, Streptomyces sp. strain KR0005 broth culture exhibited the highest phytotoxic activity. Thus, it was selected for further studies. The herbicidal active compound purified from this selected strain was identified as cycloheximide (MW, 281.; C15H23NO4) based on 1H-NMR, 13C-NMR, 2D-NMR, and high-resolution electrospray ionisation mass spectrometry analyses. Dose–response experiments revealed that the GR50 value of Digitaria ciliaris was 1.37 g L−1 to Streptomyces sp. strain KR0005 culture filtrate. In general, the inclusion of v/v 0.1% of LES270 (Alcohols, (C12-14), ethoxylated, mono ethers with sulphuric acid, sodium salts) and SF90 (Alcohols, C12-14-secondary, ethoxylated) surfactants resulted in a 14.3% decrease and a 24.1% increase in herbicidal activity, respectively, compared with Tween-20 (Polyoxyethylene sorbitan monolaurate). Mode of action experiments revealed that the KR0005 culture filtrate acted as both photosynthesis and cell membrane integrity inhibitors in a dose-dependent manner. However, further studies such as mutation and/or specific culture conditions are needed to increase the herbicidal activity of this selected strain. [ABSTRACT FROM AUTHOR]

In recent years, researchers have turned their attention to the co-cultivation of microalgae and plants as a means to enhance the growth of hydroponically cultivated plants while concurrently producing microalgal biomass. However, the techniques used require precise calibration based on plant growth responses and their interactions with the environment and cultivation conditions. This study initially focused on examining the impact of hydroponic nutrient concentrations on the growth of the microalga Chlorella sp. AARL G049. The findings revealed that hydroponic nutrient solutions with electrical conductivities (EC) of 450 µS/cm and 900 µS/cm elicited a positive response in microalgae growth, resulting in high-quality biomass characterized by an elevated lipid content and favorable properties for renewable biodiesel. The biomass also exhibited high levels of polyunsaturated fatty acids (PUFAs), indicating excellent nutritional indices. The microalgae culture and microalgae-free culture, along with inoculation-free lettuce (Lactuca sativa L. var. longifolia) and lettuce that was inoculated with plant growth actinobacteria, specifically the actinomycete Streptomyces thermocarboxydus S3, were subsequently integrated into a hydroponic deep-water culture system. The results indicated that several growth parameters of lettuce cultivated in treatments incorporating microalgae experienced a reduction of approximately 50% compared to treatments without microalgae, and lowering EC levels in the nutrient solution from 900 µS/cm to 450 µS/cm resulted in a similar approximately 50% reduction in lettuce growth. Nevertheless, the adverse impacts of microalgae and nutrient stress were alleviated through the inoculation with actinomycetes. Even though the co-cultivation system leads to reduced lettuce growth, the system enables the production of high-value microalgal biomass with exceptional biodiesel fuel properties, including superior oxidative stability (>13 h), a commendable cetane number (>62), and a high heating value (>40 MJ/kg). This biomass, with its potential as a renewable biodiesel feedstock, has the capacity to augment the overall profitability of the process. Hence, the co-cultivation of microalgae and actinomycete-inoculated lettuce appears to be a viable approach not only for hydroponic lettuce cultivation but also for the generation of microalgal biomass with potential applications in renewable energy.

Inulinase is an enzyme that catalyzes inulin to d‐fructose. This enzyme can be extracted from plants, but it is difficult to obtain it in large quantities, so its production cost is high. Therefore, microbial inulinase has great potential for industrial needs. In the last decade, there have been very few reports on actinobacterial inulinases, especially on purification and characterization of inulinase process extraction. This study aims to select actinomycetes that possess high inulinase activity from the soil. To screen inulinase‐producing bacteria, modified Czapex‐Dox agar supplemented with 1% inulin powder was used. The most effective isolate was Streptomyces sp. EFBO8, morphological and genotypic identification methods, confirmed that the strain is Streptomyces anulatus and that its nucleotide sequence has been deposited in GenBank under accession number OQ073700. To optimize inulinase production, kinetics were performed by using S. anulatus strain, which proved to be most productive with a value of 24,024 EU/mL. The enzyme was purified from the culture filtrate by precipitation with ammonium sulfate (NH4)2SO4, followed by column chromatography Sephadex (G‐50) separation. Purified protein has a molecular mass of 3331.83 Da. [ABSTRACT FROM AUTHOR]

Our previous studies revealed that a two-component system (TCS), DevS, and DevR, regulate both nitric oxide (NO) signaling and NO homeostasis in the actinobacterium Streptomyces coelicolor A3(2) M145, suggesting a reasonable system for NO-dependent metabolism. In this study, sequence alignment of DevR and DevR homologs found Asp66 (D66) and Thr196 (T196) as predicted phosphorylation sites of DevR. Phos-tag gel electrophoretic mobility shift assay suggested that D66 and T196 are involved in the phosphorylation of DevR. The respective point mutations of D66 and T196 significantly decreased the transcriptional activity of DevR, which affected nitrite production and aerial mycelium formation. These results suggested that both D66 and T196 of DevR are important for the regulation of NO homeostasis and signaling in S. coelicolor A3(2) M145. [ABSTRACT FROM AUTHOR]

A microbial fuel cell (MFC), a novel technology, is a biochemical catalyzer system that can convert the chemical energy of materials to bioelectric energy. This system can serve as a unique device for the treatment of wastewater. Based on this knowledge, we decided to study the bioenergy production ability of Actinomycete and microbial isolates in industrial glass factory wastewater as the decomposers of organic materials in this wastewater and the generation of Voltage and current in two batches and fedbatch conditions. At the most favorable condition maximum of 1.08 V (current 3.66 mA and power density 2.88 mW/m²), 81.2% chemical oxygen demand was obtained for a fed-batch system. Also, the outcomes of MFC's essential parameters, for example, pH and TDS, were studied before and after the performance of MFC. The results showed a significant decrease after the operation of the MFC. To realize which Actinomycete were the most powerful bioelectric microorganism, the growth curve and electricity performance of three kinds of Actinomycete was selected. Results showed that the C2 would be more potent because its Voltage of 0.224 V and current of 1.187 mA possessed by it would result in an excellent power density of 141.42 mW/m². [ABSTRACT FROM AUTHOR]

A novel Pseudonocardia strain DW16-2 T , isolated from duckweed ( Spirodela polyrhiza ), was taxonomically studied in detail. The analysis based on its 16S rRNA gene sequence revealed that the strain was most closely related to Pseudonocardia carboxydivorans Y8 T (98.8%), followed by Pseudonocardia tropica YIM 61452 T (98.7%), Pseudonocardia antarctica DVS 5a1 T (98.7%) and Pseudonocardia alni DSM 44104 T (98.7%). The average nucleotide identity (ANI) based on blast and digital DNA-DNA hybridization (dDDH) relatedness values between strain DW16-2 T and their closest type strains were below the threshold values for identifying a novel species. Morphological, physiological and chemotaxonomic features of strain DW16-2 T were typical for the genus Pseudonocardia by forming extensively branched substrate mycelium and aerial mycelium that fragmented into rod-shaped spore, with a smooth surface. The whole-cell hydrolysates of strain DW16-2 T contained meso -diaminopimelic acid as the diagnostic diamino acid, and the whole-cell sugars were arabinose, galactose, glucose and a trace amount of ribose. The polar lipids contained phosphatidylethanolamine, phosphatidylcholine, phosphatidylglycerol and unidentified phospholipids. The menaquinone (MK) was MK-8(H 4 ). The cellular fatty acids (>5 %) were iso -C 16 : 0 , iso -C 16 : 1  H, summed feature 3: C 16 : 1  ω7c/C 16 : 1  ω6c; C 16 : 1  ω6c/C 16 : 1  ω7c, C 17 : 1  ω8c and anteiso -C 17 : 0 . Characterization based on chemotaxonomic, phenotypic, genotypic and phylogenetic evidence demonstrated that strain DW16-2 T represents a novel species of the genus Pseudonocardia , for which the name Pseudonocardia spirodelae sp. nov. (type strain DW16-2 T = TBRC 16418 T = NBRC 115857 T ) is proprosed. In addition, the comparison of the whole genome sequences suggested that P. alni and P. antarctica belong to the same species and P. carboxydivorans is a subspecies of P. alni . Therefore, it is proposed that P. antarctica Prabahar et al . 2004 is reclassified as a later heterotypic synonym of P. alni (Evtushenko et al . 1989) Warwick et al . 1994, and P. carboxydivorans Park et al . 2008 is proposed as a subspecies of P. alni (Evtushenko et al . 1989) Warwick et al . 1994.

Four new phenolic siderophores were isolated from the actinomycete Nocardia altamirensis along with the known natural product amamistatin B and a putative biosynthetic shunt product. The structures of all compounds were elucidated through 1D and 2D NMR analyses as well as mass spectrometry. The iron-chelating properties of the retrieved metabolites were evaluated in a chrome azurol S assay.

Nitric oxide (NO) is a well-known signaling molecule in various organisms. Streptomyces undergoes complex morphological differentiation, similar to that of fungi. A recent study revealed a nitrogen oxide metabolic cycle that forms NO in Streptomyces coelicolor A3(2) M145. Further, endogenously produced NO serves as a signaling molecule. Here, we report that endogenously produced NO regulates cyclic 39,59-diguanylate (c-di- GMP) levels and controls aerial mycelium formation through the c-di-GMP-binding transcriptional regulator BldD in S. coelicolor A3(2) M145. These observations provide important insights into the mechanisms regulating morphological differentiation. This is the first study to demonstrate a link between NO and c-di-GMP in S. coelicolor A3(2) M145. Morphological differentiation is closely linked to the initiation of secondary metabolism in actinomycetes. Thus, the NO signaling-based regulation of aerial mycelium formation has potential applications in the fermentation industry employing useful actinomycetes. [ABSTRACT FROM AUTHOR]

Actinomycetes (a group of filamentous bacteria) are the dominant microbial order in the Daqu (DQ) fermentation starter and in the pit mud (PM) of the Baijiu fermentation microbiome. Actinomycetes produce many of the key enzymes and flavor components, and supply important precursors, which have a major influence on its characteristic aroma components, to other microorganisms during fermentation. This paper reviews the current progress on actinomycete research related to Baijiu fermentation, including the isolation and identification, distribution, interspecies interactions, systems biology, and main metabolites. The main metabolites and applications of the actinomycetes during Baijiu fermentation are also discussed. [ABSTRACT FROM AUTHOR]

Aims: The marine actinomycetes are a rich source of novel bioactive molecules. Especially the exotic tropical marine habitat of the Kerala coastal region favours the actinomycete diversity. The present study focuses on the isolation, purification and morphological characterization of marine actinomycetes for the discovery of new bioactive compounds. Methodology and results: A total of 280 morphologically distinct actinomycetes were isolated from marine soil and sediments of 10 different isolation sites located along the coastal region of Thiruvananthapuram district, Kerala, India using standard microbiological techniques. The physicochemical analysis of the soil samples collected from different stations was also done. Conclusion, significance and impact of study: Even though the soil/sediment samples were collected from geographically nearby places, the physicochemical parameters showed a significant variation. This may be one of the factors which may trigger the actinomycete diversity in these regions. The diversity of actinomycetes prevalent in this region could serve as a potential source for the discovery of novel biomolecules. [ABSTRACT FROM AUTHOR]

A nematicidal actinomycete strain WH06 was isolated from soil samples and was identified using 16S rRNA as Micromonospora sp. Through medium screening and fermentation, 10 metabolites were isolated from the ethyl acetate extract of its fermentation broth using Sephadex LH-20 and silica gel column chromatography. These compounds were identified as N-acetyltyramine (1), N-acetyltryptamine (2), 1-methylhydantoin (3), benzenepropanoic acid (4), cyclo-(L-Pro-L-Tyr) (5), cyclo(L-Phe-Gly) (6), catechol (7), methyl (4-hydroxyphenyl)acetate (8), 3-hydroxybenzoic acid (9), and 4-hydroxybenzoic acid (10). In an in vitro assay against Meloidogyne incognita, a root-knot nematode, compounds 1, 4, 9, and 10 show nematicidal activity. Among them, benzenepropanoic acid (4) causes 99.02% mortality of nematode at 200 μg mL−1 after 72 h. Moreover, compound 4 also displays activity in inhibiting egg hatching of M. incognita. This suggests that Micromonospora sp. WH06 is a promising candidate for biocontrol of M. incognita. [ABSTRACT FROM AUTHOR]

A novel Streptomyces strain, designated TRM 75549T, was isolated from a sample of sand in Pimo reclamation area, Taklimakan desert, Xinjiang, North–West China. Phylogenetic analyses of the 16S rRNA gene sequences placed strain TRM75549T within the genus Streptomyces with the highest similarities to Streptomyces pilosus NBRC 12772T (98.7%). Nonetheless, average nucleotide identity (ANI) value and the digital DNA–DNA hybridization (dDDH) value between strain TRM75549T and S. pilosus NBRC 12772T were, respectively, 88.2% and 44.1%, and well below 95–96% and 70% cutoff point recommended for recognizing genomospecies, respectively. A multi-locus sequence analysis of five house-keeping genes (atpD, gyrB, recA, rpoB and trpB) and phylogenomic analysis also illustrated that strain TRM75549T should also be assigned to the genus Streptomyces. Strain TRM75549T contained MK-9 (H6) and MK-9 (H8) as predominant menaquinones. The diagnostic diamino acid of cell walls were identified as LL-diaminopimelic acid and meso-diaminopimelic. The whole-cell sugar pattern of strain TRM 75549T consisted of mannose and glucose. The major fatty acids (> 5%) were iso-C14:0, iso-C15:0, anteiso-C15:0, iso-C16:1H, iso-C16:0. The polar lipids were diphosphatidylglycerol, lysophosphatidylglycerol, phosphatidylethanolamine, phospholipids, phosphatidylglycerol, phosphatidylinositol, phosphatiylinositol mannosides and unidentified phospholipids. Strain TRM75549T could be differentiated from S. pilosus NBRC 12772T, based on physiological and biochemical characteristics. Thus, strain TRM75549T is representative of a novel species of the genus Streptomyces, for which the name Streptomyces pimonensis sp. nov. is proposed. The type strain is TRM75549T (= CCTCC AA 2020054T = LMG 32221T). [ABSTRACT FROM AUTHOR]

A new Nocardiopsis species that degrades polylactic acid (PLA) was isolated from pig dung-based compost from a municipal composting facility in Japan. To obtain strains capable of efficient PLA degradation, the effect of non-enzymatic degradation of PLA was minimized by maintaining the temperature at or below 37 °C. Screening 15 animal waste-based compost samples, consisting of pig dung, cow dung, horse dung, or chicken droppings, revealed that compost derived from pig dung was most efficient for degradation of PLA films. Hence, pig waste-based compost was used to isolate PLA-degrading microorganisms by screening for PLA-degrading microorganisms in compost using an agar plate-based method in which an emulsifier was omitted to avoid selecting strains that assimilated the emulsifier instead of PLA in the medium. Repeated enrichment obtained six strains. The one that exhibited stable PLA degradation on agar plates was subjected to genomic analysis and identified as Nocardiopsis chromatogenes, an actinomycete. [ABSTRACT FROM AUTHOR]

Quorum-sensing (QS) is involved in numerous physiological processes in bacteria, such as biofilm formation, sporulation, and virulence formation. Therefore, the search for new quorum-sensing inhibitors (QSI) is a promising strategy that opens up a new perspective for controlling QS-mediated bacterial pathogens. To explore new QSIs, a strain named Streptomyces sp. D67 with QS inhibitory activity was isolated from the soil of the arid zone around the Kumutag Desert in Xinjiang. Phylogenetic analyses demonstrated that strain D67 shared the highest similarity with Streptomyces ardesiacus NBRC 15402T (98.39%), which indicated it represented a potential novel species in the Streptomyces genus. The fermentation crude extracts of strain D67 can effectively reduce the violacein production produced by Chromobacterium violaceum CV026 and the swarming and swimming abilities of Pseudomonas aeruginosa. It also has significant inhibitory activity on the production of virulence factors such as biofilm, pyocyanin, and rhamnolipids of P. aeruginosa in a significant concentration-dependent manner, but not on protease activity. A total of 618 compounds were identified from the fermentation crude extracts of strain D67 by LC-MS, and 19 compounds with significant QS inhibitory activity were observed. Overall, the strain with QS inhibitory activity was screened from Kumutag Desert in Xinjiang for the first time, which provided a basis for further research and development of new QSI.

[Objective] To put the theoretical basis on the biological control of actinomycetes to nematode, the effects of 3 actinomycetes on controlling root-knot nematode disease and growth promotion of cucumber were probed. [Method] The seeds of 9930 cultivar, which was susceptible to Meloidogyne incognita, was sown in the pots filled with the sterilized substrate, and the ones with 1.5 g/L Streptomyces pac-tum (Act12), Streptomyces albidoflavu (T4), Streptomyces rochei (D74), respectively. When the seedlings were at the stage of two fully expanded true leaves, 2 niL egg suspensions of Meloidogyne incognita containing 1 500 eggs mL-1 were inoculated in the substrates nearby the roots of seedlings, and these treatments were marked as Mi, Act12 + Mi, T4 + Mi, D74 + ML The galls number and gall index were surveyed at 30 d and 58 d after inoculation of root-knot netnatode, and the stem thickness, fresh weight of underground and aboveground and the total fresh weight of plant were measured; the size of giant cell was observed at 30 d after inoculation under a microscope by using hematoxylineosin staining to make paraffin sections of the galls. The comprehensive membership function was used to evaluate the effects of actinomy-cetes on controlling the disease of Meloidogyne incognita and the growth promotion of cucumber. [Result] 1) Compared with that of treatment Mi, the galls number on the seedling roots of treatment Act12 + Mi, T4 + Mi andD74 + Mi decreased significantly by 44.56%, 39.26% and 41.38%, respectively. The gall indexes of T4 + Mi and D74 + Mi also decreased significantly. For the adult plants, the gall number and the gall index were also significantly lower of the treatment T4 + Mi than that of Mi. The results of paraffin section showed that 3 actinomycetes significantly inhibited the expansion of giant cell in cucumber seedling roots comparing with that of Mi treatment. The inhibiting effects were T4, D74, and Actl2 in order. 2) Comparing with that of the control (CK) which was inoculated with neither actinomycete nor root-knot netna-tode, the underground fresh weight and aboveground fresh weight of the treatments inoculated with either T4 or D74 increased significantly, and the number of fibrous roots increased significantly. The underground fresh weight of treatment inoculated with Act12 also increased significantly. For the adult plants, the aboveground fresh weight, underground fresh weight and the total fresh weight of T4 + Mi significantly increased comparing with that of treatment Mi, and the underground fresh weight of Act12 + Mi and D74 + Mi also increased significantly. In summary, pre-inoculation of T4 promoted the cucumber plants to grow well. 3) It showed that the values of T4 was the largest, and the next was D74, and then the Act12. [Conclusion] All 3 actinomycetes had a significant effect on the growth promotion and the disease controlling of root-knot nematode. Pre-inoculating of Streptomyces albidoflavus (T4) was the best. [ABSTRACT FROM AUTHOR]

Analysis of an antimicrobial extract prepared from the culture broth of the marine-derived actinomycete Nocardiopsis synnemataformans (HT06 strain) led to the isolation of a new C-glucoside benzoic acid derivative, 4βC-glucopyranosyl-3,5-dihydroxy-2-methoxybenzoic acid (1), along with eight known compounds, norharman (2), (E)-4-(3-hydroxy-4-methoxyphenyl)but-3-en-2-one (3), methyl 2,3,4,9-tetrahydro-1H-pyrido[3,4-b]indole-3-carboxylate (4), 1H-indole-3-ethanol (5), 4-hydroxy-3-methoxybenzaldehyde (6), 3-phenylpropanoic acid (7), phloretic acid (8), and cinnamic acid (9). The antimicrobial activity of all isolated compounds was assayed. [ABSTRACT FROM AUTHOR]

Abstract Red alga dulse contains xylan with β(1→3)/β(1→4) linkages. We previously prepared xylooligosaccharides (XOSs) from dulse xylan; however, the product contained many d-xylose residues and fewer XOSs with β(1→3) linkages. To improve the efficiency of XOS production, we prepared two recombinant endoxylanases from Streptomyces thermogriseus (StXyl10 and StXyl11). Comparing the k cat/K m values for dulse xylan, this value from StXyl10 was approximately two times higher than that from StXyl11. We then determined the suitable conditions for XOS production. As a result, dulse XOS was prepared by the successive hydrolysis of 10 mg/mL dulse xylan by 0.5 μg/mL StXyl10 for 4 h at 50 °C and then 2.0 μg/mL StXyl11 for 36 h at 60 °C. Xylan was converted into 95.8% XOS, including 59.7% XOS with a β(1→3) linkage and 0.97% d-xylose. Our study provides useful information for the production of XOSs with β(1→3) linkages.

Abstract Background Bio-nanotechnology is considered as one of the low-cost approaches that have been utilized in production of nanomaterials. The current research aimed at investigating the influence of different types of Actinomycete strains on the final properties of silver nanoparticles (AgNPs) such as size, shape, polydispersity, and antibacterial properties. For this purpose, the following techniques were employed UV spectrophotometer, SDS-PAGE electrophoresis, TEM, FTIR, antibacterial agar diffusion test, and Zetasizer. Results It was found that among 34 Streptomyces isolates collected from the soil, Streptomyces spiralis and Streptomyces rochei were able to reduce silver nitrate into sliver nanoparticles. The diversity and molecular weights of extracellular proteins secreted by these stains were different as proved by SDS-PAGE technique. This consequently resulted in differences in polydispersity of AgNPs which indicate that the sizes of AgNPs were highly dependent on the amount, molecular sizes, and diversity of extracellular matrix proteins of the microorganism. Conclusion This article might give an insight about the importance of molecular sizes of biomacromolecules such as proteins on the physical properties of biogenic synthesized nanoparticles.

Abstract The genera Williamsia and Segniliparus are of aerobic actinomycetes and at the time of writing, they have 12 and 2 species, respectively. These genera cause various infections in humans. In this review, we surveyed their taxonomy, isolation, identification, as well as their role to cause human infections.

Copyright of Acta Agronomica Sinica is the property of Crop Science Society of China and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Northwest A & F University - Natural Science Edition is the property of Editorial Department of Journal of Northwest A&F University (Natural Science Edition) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Cytochrome P450 monooxygenases (CYPs/P450s) are heme thiolate proteins present in species across the biological kingdoms. By virtue of their broad substrate promiscuity and regio- and stereo-selectivity, these enzymes enhance or attribute diversity to secondary metabolites. Actinomycetes species are well-known producers of secondary metabolites, especially Salinispora species. Despite the importance of P450s, a comprehensive comparative analysis of P450s and their role in secondary metabolism in Salinispora species is not reported. We therefore analyzed P450s in 126 strains from three different species Salinispora arenicola, S. pacifica, and S. tropica. The study revealed the presence of 2643 P450s that can be grouped into 45 families and 103 subfamilies. CYP107 and CYP125 families are conserved, and CYP105 and CYP107 families are bloomed (a P450 family with many members) across Salinispora species. Analysis of P450s that are part of secondary metabolite biosynthetic gene clusters (smBGCs) revealed Salinispora species have an unprecedented number of P450s (1236 P450s-47%) part of smBGCs compared to other bacterial species belonging to the genera Streptomyces (23%) and Mycobacterium (11%), phyla Cyanobacteria (8%) and Firmicutes (18%) and the classes Alphaproteobacteria (2%) and Gammaproteobacteria (18%). A peculiar characteristic of up to six P450s in smBGCs was observed in Salinispora species. Future characterization Salinispora species P450s and their smBGCs have the potential for discovering novel secondary metabolites. [ABSTRACT FROM AUTHOR]

Under the screening programme for organisms producing substances with hypolipidemic and antifungal activity Streptomyces sp. 17 was isolated. The taxonomic properties of the strain were investigated. Active compounds, i.e. oligomycin A and oligomycin SC- II were isolated from a complex biosynthetic product. Oligomycin A showed high antifungal activity whereas oligomycin SC-II had also moderate antibacterial activity.

The aerobic, thermophilic Actinobacterium, Thermobifida fusca has been proposed as an organism to be used for the efficient conversion of plant biomass to fatty acid-derived precursors of biofuels or biorenewable chemicals. Despite the potential of T. fusca to catabolize plant biomass, there is remarkably little data available concerning the natural ability of this organism to produce fatty acids. Therefore, we determined the fatty acids that T. fusca produces when it is grown on different carbon sources (i.e., glucose, cellobiose, cellulose and avicel) and at two different growth temperatures, namely at the optimal growth temperature of 50°C and at a suboptimal temperature of 37°C. These analyses establish that T. fusca produces a combination of linear and branched chain fatty acids (BCFAs), including iso-, anteiso-, and 10-methyl BCFAs that range between 14- and 18-carbons in length. Although different carbon sources and growth temperatures both quantitatively and qualitatively affect the fatty acid profiles produced by T. fusca, growth temperature is the greater modifier of these traits. Additionally, genome scanning enabled the identification of many of the fatty acid biosynthetic genes encoded by T. fusca.