Bloodstream infection by Rhodococcus corynebacterioides in a pediatric patient diagnosed with high-risk retinoblastoma / Infección del torrente sanguíneo por Rhodococcus corynebacterioides en un paciente pediátrico con diagnóstico de retinoblastoma de alto riesgo

Abstract Rhodococcus is a pathogen that is known to cause infections in animals and humans, mainly in cases of immunocompromised patients. A case of a pediatric cancer patient suffering from a bloodstream infection caused by Rhodococcus corynebacterioides was described in this work. Gram positive rods were isolated from blood cultures. The target bacterium was identified using a combination of biochemical tests, the MALDI-TOF mass spectrometry technique, and the analysis of the 16S rRNA sequence. Moreover, an antimicrobial susceptibility test was performed using the E-test. The isolated bacterium was identified as R. corynebacterioides. The 3-year-old patient was successfully treated with vancomycin and meropenem. This is the first published report of R. corynebacterioides in a pediatric patient diagnosed with retinoblastoma that developed a bloodstream infection. R. corynebacterioides should be considered among the opportunistic infectious agents affecting pediatric cancer patients.

Resumen Rhodococcus es un patógeno conocido por causar infecciones en animales y humanos, principalmente en pacientes inmunocomprometidos. En este trabajo se describe el caso de un paciente pediátrico con cáncer que presentó una infección del torrente sanguíneo causada por Rhodococcus corynebacterioides. A partir de hemocultivos, se aislaron bacilos gram positivos. La bacteria diana fue identificada usando una combinación de pruebas bioquímicas, por espectrometría de masas MALDI-TOF y por el análisis de la secuencia del gen 16S ARNr. Además, se realizó una prueba de sensibilidad a los antimicrobianos utilizando E-test. La cepa bacteriana se identificó como R. corynebacterioides. El paciente, de 3 años, fue tratado con vancomicina y meropenem, exitosamente. Este es el primer reporte de R. corynebacterioides como agente causal de una infección del torrente sanguíneo en un paciente pediátrico con retinoblastoma. R. corynebacterioides debe considerarse entre los agentes infecciosos oportunistas que afectan a los pacientes pediátricos con cáncer.

Marine actinomycetes from the Kerala coastal region as a potential expedient for the natural drug discovery

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.

Lytic polysaccharide monooxygenase of soil actinomycete with potential use for lignocellulose biodegradation

Aims@#Lytic polysaccharide monooxygenase (LPMO) is an enzyme capable of cleaving glycoside bonds of recalcitrant polysaccharides through an oxidative mechanism. LPMO activity, in synergy with hydrolytic enzymes, increases the production of monomer sugars from the biodegradation of lignocellulose. This study was aimed at evaluating actinomycete S2 strain LPMO activity based on the release of xylose as one of reducing sugar and hydrogen peroxide (H2O2) in the course of lignocellulosic biodegradation. @*Methodology and results@#The oxidation activity of LPMO from actinomycete S2 strain was measured by using the substrate of Avicel supplemented with ascorbic acid and copper ions (Cu2+) to identify its effect on the release of xylose as one of reducing sugar. The optimum incubation time for the LPMO production was also conducted. Further, H2O2 quantitative analysis was performed as by-product of LPMO activity and 16S rRNA gene sequence of actinomycete S2 strain were subsequently determined. We found that supplementation of 1 mM ascorbic acid and 0.2 mM Cu2+ increased xylose as one of reducing sugar production by up to 5-fold from 255.03 to 1290 μg/mL after an optimal incubation period of 6 days. Based on H2O2 production, the LPMO activity of actinomycete S2 strain was 0.019 ± 0.001 U/mL. There is likelihood that LPMO activity derived from actinomycete S2 strain has a synergistic effect with the activity of other lignocellulose-degrading enzymes. This actinomycete showed 99% similarity to the 16S rRNA gene sequence of Streptomyces avermitilis strain EAAG80. @*Conclusion, significance, and impact of study@#LPMO enzyme activity from actinomycete S2 strain as determined by the production of reducing sugar and H2O2 was greatly increased by supplementation with ascorbic acid as an electron donor and Cu2+ ions. To the best of our knowledge, this is the first elucidation of LPMO activity from an indigenous Indonesian actinomycete.

Enhanced detection of antimicrobial activities and secondary metabolites production from Plantactinospora sp. KBS50 cultivated using the OSMAC fermentation approach

Aims@#A rare marine-derived actinomycete, Plantactinospora sp. KBS50, has been identified as a potential source of bioactive secondary metabolites compounds. The present study aimed to evaluate the secondary metabolites biosynthetic capability of strain KBS50 using the One Strain Many Compound (OSMAC) fermentation strategy. @*Methodology and results@#Strain KBS50 was fermented in a basal medium (ISP2) supplemented with selected biological and chemical elicitors, as well as cultivation at different pH value and incubation temperature. Statistical analysis revealed that the antimicrobial activities were significantly increased, as compared to the basal medium, ISP2. Similarly, the comparative High Performance Liquid Chromatography (HPLC) analysis showed an increase in secondary metabolites production, as well as the detection of potential new metabolites, particularly from the crude extracts of ISP2 medium supplemented with 1% (w/v) sodium chloride and with the culture filtrate of Aspergillus niger. The bioassay-guided fractionation showed that the extract of strain KBS50 contains multiple compounds with antibacterial activity against the Gram-positive strains. Further fractionation led to the isolation of two semi-pure compounds (compound 3 and 4) with bactericidal properties against Staphylococcus aureus. The Minimum Inhibitory Concentration (MIC) values of compound 3 and 4 were recorded at 7.81 μg/mL and 62.50 μg/mL, respectively. The minimum bactericidal concentration (MBC) for compound 3 was recorded at 15.63 μg/mL while the MBC for compound 4 was recorded as 125.00 μg/mL. @*Conclusion, significance and impact of study@#The OSMAC fermentation strategy used in this study had successfully enhanced the detection of antibiotics and secondary metabolites from Plantactinospora sp. KBS50. The bioassay-guided fractionation further established the capability of strain KBS50 as a source of bioactive secondary metabolite compounds with potent antimicrobial activity.

Antimicrobial activities of Plantactinospora sp. KBS50, a rare marine-derived actinomycete from the coastal area of Sarawak

Aims@#An actinomycete strain, designated KBS50, was isolated from a beach sediment sample collected from the Santubong area in Sarawak, Malaysia. This study reports on the identification, characterization and evaluation of the antimicrobial potential of this rare actinomycete. @*Methodology and results@#KBS50 was identified as a potentially new species of Plantactinospora genus using the 16S rRNA gene sequence analysis. The rare actinomycete showed distinct morphological and physiological characteristics from other species of Plantactinospora. KBS50 exhibited strong antagonistic activities against Gram-positive bacteria (Staphylococcus aureus and Bacillus subtilis) and fungi (Aspergillus niger, Ganoderma boninense, and Rhizoctonia solani). The actinomycete also tested positive for proteolytic activity. Meanwhile, secondary screening of the cell-free culture broths and the ethyl acetate crude extracts detected antimicrobial activity against the Gram-positive bacteria only. The minimum inhibitory concentration of the crude extract against B. subtilis and S. aureus was 5.21±1.30 μg/mL and 15.63±0.00 μg/mL, respectively. @*Conclusion, significance and impact of study@#The results presented in this paper provided an insight into the capability of Plantactinospora sp. KBS50 as a potential source of bioactive secondary metabolites compounds. This study also showed that the marine-associated environment such as the coastal area in Sarawak can be a valuable source of unique actinomycetes that can be exploited for natural product discovery.

Bioactive phenazines from an earwig-associated Streptomyces sp / 中国天然药物

Three new phenazine-type compounds, named phenazines SA-SC (1-3), together with four new natural products (4-7), were isolated from the fermentation broth of an earwig-associated Streptomyces sp. NA04227. The structures of these compounds were determined by extensive analyses of NMR, high resolution mass spectroscopic data, as well as single-crystal X-ray diffraction measurement. Sequencing and analysis of the genome data allowed us to identify the gene cluster (spz) and propose a biosynthetic pathway for these phenazine-type compounds. Additionally, compounds 1-5 exhibited moderate inhibitory activity against acetylcholinesterase (AChE), and compound 3 showed antimicrobial activities against Micrococcus luteus.

Poly(DL-lactide)-degrading enzyme production by immobilized Actinomadura keratinilytica strain T16-1 in a 5-L fermenter under various fermentation processes

Background: Poly(DL-lactic acid), or PDLLA, is a biodegradable polymer that can be hydrolyzed by various types of enzymes. The protease produced by Actinomadura keratinilytica strain T16-1 was previously reported to have PDLLA depolymerase activity. However, few studies have reported on PDLLA-degrading enzyme production by bacteria. Therefore, the aims of this study were to determine a suitable immobilization material for PDLLA-degrading enzyme production and optimize PDLLA-degrading enzyme production by using immobilized A. keratinilytica strain T16-1 under various fermentation process conditions in a stirrer fermenter. Results: Among the tested immobilization materials, a scrub pad was the best immobilizer, giving an enzyme activity of 30.03 U/mL in a shake-flask scale. The maximum enzyme activity was obtained at aeration 0.25 vvm, agitation 170 rpm, 45°C, and 48 h of cultivation time. Under these conditions, a PDLLA-degrading enzyme production of 766.33 U/mL with 15.97 U/mL·h productivity was observed using batch fermentation in a 5-L stirrer fermenter. Increased enzyme activity and productivity were observed in repeated-batch (942.67 U/mL and 19.64 U/mL·h) and continuous fermentation (796.43 U/mL and 16.58 U/mL·h) at a dilution rate of 0.013/h. Scaled-up production of the enzyme in a 10-L stirrer bioreactor using the optimized conditions showed a maximum enzyme activity of 578.67 U/mL and a productivity of 12.06 U/mL·h. Conclusions: This research successfully scaled-up the enzyme production to 5 and 10 L in a stirrer fermenter and is helpful for many applications of poly(lactic acid).

Isolation, Characterization, Antioxidant, Antimicrobial and Cytotoxic Effect of Marine Actinomycete, Streptomyces Carpaticus MK-01, against Fish Pathogens

ABSTRACT Present study aim to evaluate the antimicrobial, antioxidant and cytotoxic potential of crude extract of Marine Streptomyces carpaticus MK-01 isolated from seawater collected from Daejeong-cost of Jeju Island. About 24 actinomycetes strains were isolated and subjected to morphological and molecular analysis that confirmed the isolate as S. carpaticus MK-01. Crude ethyl acetate extract of MK-01 strain showed extensive antibacterial activity against Gram-positive fish pathogenic bacteria namely Streptococcus iniae and S. parauberis with a maximum zone of inhibition (0.92±0.03mm) was recorded against S. parauberis at the minimum extract concentration (3.12µg/ml). The MK-01 ethyl acetate extract shows dose dependant significant increase in antioxidant activity. The 50% cytotoxic concentration (CC50) of MK-01 ethyl acetate extract was attained at 53.71 μg/ml and the effective concentration 50 (EC50) against virus-infected Epithelioma papulosum cyprini cell lines was 8.72 μg/ml of S. carpaticus MK-01 crude ethyl acetate extract.

Screening, identification and antimicrobial activity of alkaloid produced by endophytic actinomycetes from Fritillaria unibracteata in western Sichuan plateau / 中国中药杂志

To explore the resource of endophytic actinomycete in Fritillaria unibracteata, and alleviate the shortage of F. unibracteata resource, using F. unibracteata as experimental materials which growth in the western Sichuan plateau and cut its healthy bulb. Pure culture, insert, TLC and Oxford cup were applied to observe the mycelial morphology, research the ability of producing alkaloid and its antibacterial activity. Totally, 14 endophytic actinomycete strains were isolated by using Gao culture media. Based on the color reaction, 5 typical strains were selected for producing alkaloid. Through the TLC technique, all strains produced 2 obvious alkaloids spots. Antibacterial activity determination showed that the antimicrobial effects of 2 strains is prominent, the diameter up to 11 mm.16S rRNA gene sequence comparison analysis showed that 5 strains belonging to the Streptomyces. The alkaloids produced by endophytic actinomycetes are not related to F. unibracteata, but its fermentation liquid has antibacterial effect, it is worthy of further study.

Comparative analysis of chemical constituents, antimicrobial and antioxidant activities of ethylacetate extracts of Polygonum cuspidatum and its endophytic actinomycete, Streptomyces sp. A0916 / 中国天然药物

The present study investigated the chemical composition of ethylacetate extracts from an endophytic actinomycete Streptomyces sp. A0916 and its host Polygonum cuspidatum. A comparative analysis of the antimicrobial and antioxidant properties of the extracts was also conducted. 32 compounds of P. cuspidatum and 23 compounds of Streptomyces sp. A0916 were isolated and identified by GC/MS. Antimicrobial activities of the extracts were evaluated using eight microbial strains (3 Gram-positive bacteria, 3 Gram-negative bacteria, and 2 fungi). The Streptomyces sp. A0916 extracts showed a wide range of antimicrobial activities and presented greater antimicrobial effectiveness than the P. cuspidatum extracts. The minimum inhibitory concentration (MIC) of Streptomyces sp. A0916 extracts against the ampicillin-resistant strain Enterococcus faecium SIIA843 was 32 μg·mL(-1). Furthermore, the extracts had greater antimicrobial effect against Gram-positive bacteria than Gram-negative bacteria. Finally, the antioxidant activity of the Streptomyces sp. A0916 extracts was equal to that of the P. cuspidatum extracts. In conclusion, our results suggest that the endophytic actinomycetes of the medicinal plants are an important source of bioactive substances.

Deuteromethylactin B from a Freshwater-derived Streptomyces sp

Compared to their terrestrial and marine counterparts, little is known about the capacity of freshwater-derived actinomycete bacteria to produce novel secondary metabolites. In the current study, we highlight the disparities that exist between cultivation-independent and -dependent analyses of actinomycete communities from four locations in Lake Michigan sediment. Furthermore, through phylogenetic analysis of strains isolated from these locations, we identified a Streptomyces sp., strain B025, as being distinct from other Streptomyces spp. isolated from sediment. Upon fermentation this strain produced a rare class of eight-membered lactone secondary metabolites, which have been for their antitumor properties. We used spectroscopic and chemical derivitization techniques to characterize octalactin B (1) in addition to its corresponding novel, unnatural degradation product (2).

Salternamide E from a Saltern-derived Marine Actinomycete Streptomyces sp

Comprehensive chemical analysis of extracts and fractions of marine actinomycete strains led to the discovery of a new minor secondary metabolite, salternamide E (1), from a saltern-derived halophilic Streptomyces strain. The planar structure of salternamide E (1) was elucidated by a combinational analysis of spectroscopic data including NMR, MS, UV, and IR. The absolute configuration of salternamide E (1) was determined by circular dichroism spectroscopic analysis. Salternamide E displayed weak cytotoxicity against various human carcinoma cell lines.

Sepration and antitumor activities of secondary metabolites from marine actino-mycete Nocardiopsis sp .SCSIO 11492 / 药学实践杂志

Objective To explore cytotoxic secondary metabolites from a marine actinomycete Nocardiopsis sp .SCSIO 11492 .Methods Isolation and purification were carried out by column chromatography over silica gel ,Sephadex LH-20 ,and ODS structures of the isolates were identified mainly by NMR spectroscopic data .And cytotoxic bioassay was performed using MTT method .Results Five compounds were identified as 2′-deoxyadenosine (1) ,2′-deoxythymidine (2) ,2′-deoxyuidine (3) ,uridine (4) ,1-O-palmitoyl-3-d-galactosyl-sn-glycerol spongilipid (5) .Compound 5 exhibited weak cytotoxic activity with IC50 value of 10 .9 μmol/L .Conclusion Five compounds were obtained from a marine actinomycete Nocardiopsis sp .SCSIO 11492 .All five compounds were reported for the first time from this genus .Compound 5 could be the bioactive compound re-sponsible for the cytotoxic activity of Nocardiopsis sp .SCSIO 11492 .

Biological control of phytopathogenic fungi by endophytic actinomycetes isolated from maize (Zea mays L.)

This work aimed a survey on the biodiversity of maize endophytic actinomycete, and an evaluation of their potential to control the phytopathogenic fungi. From several regions of São Paulo state, 40 strains were isolated from the healthy maize plants. The identification of these strains, based on morphological properties and fatty acid methyl ester (FAME) profile showed that most of them belonged to the Streptomyces genus. These isolates were first screened for the growth inhibition of phytopathogenic fungi and results showed that all the isolate were able to inhibit the development of at least one tested pathogen. Two selected isolates were then evaluated for the control of P. aphanidermatum in cucumber (Cucumis sativa L.) under greenhouse conditions. Isolate 16R3B was able to reduce up to 71% damping-off incidence whereas isolate 14F1D/2 reduced the disease incidence by 36%. Damping- off control in cucumber, mainly for the isolate 16R3B, suggested for its use in greenhouse cucumber producing fields and to be tested in field trials.

Studies on antimicrobial activity of actinomycetes against MDR wound bacterial isolates.

A total of five different actinomycete isolates were recovered from mine soil samples collected from Salem, Tamilnadu. These were then assessed for their antibacterial activity against five multidrug resistance bacterial wound isolates. All five isolates of actinomycete exhibited antagonistic activity. The zone of inhibition ranged between 11-25 mm. Among the 5 isolates of actinomycetes A5 isolate has highest antibacterial activity against S.aureus and E.coli. Out of five bacterial isolates Pseudomonas aeruginosa was highly suppressed by actinomycetes followed by E.coli. The maximum antibacterial activity was observed on 14th day incubation. The result of primary screening reveals that most of the active actinomycetes isolates were active against gram positive bacteria (S.aureus) than gram negative bacteria. The antibiotic profile of these isolates underlined their potential as a source of novel antibiotics.

Cyclic dipeptides in actinomycete Brevibacterium sp. associated with sea cucumber Apostichopus japonicus Selenka: Isolation and identification / 第二军医大学学报

Objective To investigate the secondary metabolites of actinomycete Brevibacterium sp. associated with the sea cucumber Apostichopus japonicus Selenka. Methods The ethyl acetate extract of the actinomycete was purified by repeated column chromatography on silica gel, Sephadex LH-20, and high-performance liquid chromatography (HPLC) to obtain pure compounds; and the compound structures were elucidated by spectroscopic analysis (nuclear magnetic resonance, NMR; mass spectrometry, MS) and the results were compared with the previously reported data. Results Seven compounds were isolated: cyclo-(L-Pro-L-Phe) (1), cyclo-(L-Pro-L-Met) (2), cyclo-(L-Pro-L-Tyr) (3), cyclo-(L-Pro-L-Val) (4), cyclo-(L-Pro-L-Pro) (5), cyclo-(L-Val-Gly) (6), and cyclo-(L-Pro-L-Leu) (7). Conclusion This is the first report on the secondary metabolites of microorganisms associated with the sea cucumber Apostichopus japonicus Selenka, and all the seven compounds have been reported from the actinomycete Brevibacterium sp. for the first time.

Components in Antineoplastic Actinomycete Strain(N2010-37)of Bottom Mud in Mangrove / 中草药·英文版

Objective To study the antitumor components from an actinomycete strain(N2010-37)of bottom mud in Zhanjiang Mangrove,South China Sea.Methods The components were isolated and purified by chromatographic techniques and recrystallization,and the structures were identified by spectral methods together with physicochemical analyses.The antitumor effects of these components were tested in vitro by MTT method.Results Three compounds were identified including two anthrones and one novel lactone.They are(3S,4R,7R,8R,9S)-3,8-dihydroxy-4,7,9-trimethyl-2,6-cyclononanediolacetone(1),2-hydroxy-l-methoxy-3-methylanthraquinone(2),and 1,6,8-thihydroxy-3-methyl-anthraquinone(3).Conclusion Compound 1 is a new compound,and compounds 1 and 3 show the favorablecytotoxic activities against human chronic granulocytic leukemia cell line K562 strain by MTT method in vitro.

Chemical constituents of antineoplastic actinomycete strain (N2010-37) of bottom mud in mangrove (I) / 中草药

Objective: To study the chemical constituents in the cultured filaments of an antitumor actinomycete strain (N2010-37). Methods: Compounds were isolated and purified by chromatographic techniques and recrystallization, and the structures were identified by spectral methods together with physicochemical analysis. The antitumor effects of these compounds were tested in vitro by MTT method. Results: Three compounds were identified including two anthrones and one novel macrolide. They were (3S, 4R, 7R, 8R, 9S)-3, 8-dihydroxy-4, 7,9-trimethyl-2,6-cyclononanediiolacetone (1), 2-hydroxy-1-methoxy-3- methylanthraquinone (2), and 1, 6, 8-thihydroxy-3-methylanthraquinone (3). Conclusion: Compound 1 is a new compound, and compounds 1 and 3 show the favorable cytotoxic activity against human chronic granulocytic leukemia cell line K562 strain by MTT method in vitro.

Screening for bioactive mutants with antitumor activity from an actinomycetic wild-type strain without antitumor activity by antibiotic-resistant mutation technique and by coupled with chemical mutagen-induced mutation / 军事医学科学院院刊

Objective To obtain antibiotic-resistant mutants producing metabolites with antitumor activity from wild-type actinomycete strains without antitumor activity. Methods An actinomycete strain L35-1 was used as an initial strain for obtaining antibiotic-resistant mutants, which is a marine-derived wild-type strain without antitumor activity with an inhibition rate of 2.8% at the 1000 μg/ml of high sample concentration on K562 cells. The antibiotic-resistant mutants both from auto-mutagenesis and chemical mutagen-induced mutagenesis were selected by single colony isolation on antibiotic-containing plates according to the method for obtaining drug-resistant mutants in ribosome engineering. The antitumor activity was assayed by the MTT method using K562 cells for the mutants with aqueous acetone extracts of the whole broth of their fermentation.Results A total of 114 neomycin-resistant (ner) and 68 streptomycin-resistant (str) mutants, all from auto-mutagenesis, was obtained on drug-containing plates. Among them, the 7 ner and 3 str mutants appeared to be bioactive with an inhibition rate above 20% at the 100 μg/ml sample concentration on K562 cells. On the other hand, 41 str and 32 ner mutants from DES-induced mutagenesis and 46 ner mutants from NTG-induced mutagenesis were obtained by mutagen-induced mutation coupled with the single colony isolation on antibiotic-containing plates, among which, one str mutant from DES-induced mutagenesis and one ner mutant from NTG-induced mutagenesis were bioactive with an inhibition rate over 20% at the 100 μg/ml sample concentration on K562 cells. Conclusions The present result has revealed that the wild-type actinomycete strains without bioactivity might become a great source initial strains to obtain bioactive mutants by drug-resistant mutation technique.

A new approach for exploiting microbial new strain resources for drug screening / 国际药学研究杂志

Generally absolute majority of wild-type microbial strains do not produce bioactive metabolites, resulting in large numbers of so-called 'useless strains' stocked or destroyed. These strains, however, would become a great source of bioactive meabolites if their secondary metabolism could be altered to produce diverse metabolites. We have therefore undertaken a research work on exploiting microbial new strain resources for drug screening by altering secondary metabolism of the 'useless strains' to discover bioactive metabolites. A considerable progress with expectant advantage desired has been made in the studies on marine-derived actinomycetic and fungal strains. This paper summarizes our research results including several new developments in brief.