Rare case of coexisting hepatic, splenic, and vertebral hemangiomas - A case report.

Synchronous existence of hepatic, splenic, and skeletal hemangiomas has not been reported previously in the English literature to our knowledge. In this case report, we present a case of coexistence of hepatic, splenic, and skeletal hemangiomas in a 30-year-old woman with on and off bilateral lumbar region pain and no significant past medical history. Radiological investigations, including ultrasound and computed tomography and magnetic resonance imaging helped identify the synchronous existence of hepatic, splenic, and skeletal hemangiomas. The patient improved with conservative management and was kept on follow-ups. Although there have been reports of coexistence of splenic and hepatic hemangiomas in the literature, to our knowledge, this is the first report of synchronous existence of hepatic, splenic, and skeletal hemangiomas.

Unravelling the hidden power of esterases for biomanufacturing of short-chain esters.

Microbial production of esters has recently garnered wide attention, but the current production metrics are low. Evidently, the ester precursors (organic acids and alcohols) can be accumulated at higher titers by microbes like Escherichia coli. Hence, we hypothesized that their 'direct esterification' using esterases will be efficient. We engineered esterases from various microorganisms into E. coli, along with overexpression of ethanol and lactate pathway genes. High cell density fermentation exhibited the strains possessing esterase-A (SSL76) and carbohydrate esterase (SSL74) as the potent candidates. Fed-batch fermentation at pH 7 resulted in 80 mg/L of ethyl acetate and 10 mg/L of ethyl lactate accumulation by SSL76. At pH 6, the total ester titer improved by 2.5-fold, with SSL76 producing 225 mg/L of ethyl acetate, and 18.2 mg/L of ethyl lactate, the highest reported titer in E. coli. To our knowledge, this is the first successful demonstration of short-chain ester production by engineering 'esterases' in E. coli.

Corynebacterium glutamicum as an Efficient Omnivorous Microbial Host for the Bioconversion of Lignocellulosic Biomass.

Corynebacterium glutamicum has been successfully employed for the industrial production of amino acids and other bioproducts, partially due to its native ability to utilize a wide range of carbon substrates. We demonstrated C. glutamicum as an efficient microbial host for utilizing diverse carbon substrates present in biomass hydrolysates, such as glucose, arabinose, and xylose, in addition to its natural ability to assimilate lignin-derived aromatics. As a case study to demonstrate its bioproduction capabilities, L-lactate was chosen as the primary fermentation end product along with acetate and succinate. C. glutamicum was found to grow well in different aromatics (benzoic acid, cinnamic acid, vanillic acid, and p-coumaric acid) up to a concentration of 40 mM. Besides, 13C-fingerprinting confirmed that carbon from aromatics enter the primary metabolism via TCA cycle confirming the presence of ß-ketoadipate pathway in C. glutamicum. 13C-fingerprinting in the presence of both glucose and aromatics also revealed coumarate to be the most preferred aromatic by C. glutamicum contributing 74 and 59% of its carbon for the synthesis of glutamate and aspartate respectively. 13C-fingerprinting also confirmed the activity of ortho-cleavage pathway, anaplerotic pathway, and cataplerotic pathways. Finally, the engineered C. glutamicum strain grew well in biomass hydrolysate containing pentose and hexose sugars and produced L-lactate at a concentration of 47.9 g/L and a yield of 0.639 g/g from sugars with simultaneous utilization of aromatics. Succinate and acetate co-products were produced at concentrations of 8.9 g/L and 3.2 g/L, respectively. Our findings open the door to valorize all the major carbon components of biomass hydrolysate by using C. glutamicum as a microbial host for biomanufacturing.

Treatment of long bone infection by a biodegradable bone cement releasing antibiotics in human.

Repair of methicillin-resistant Staphylococcal (MRSA) chronic osteomyelitis and resulting bone defect is one of the major challenges in orthopaedics. Previous study has shown the effectiveness of antibiotic loaded biodegradable composite bone cement with in vitro tests and in the treatment of experimental osteomyelitis. The cement is composed of poly(lactide-co-glycolide) encapsulated antibiotic-biphasic calcium phosphate granule complex and additive antibiotic powder in gypsum binder. In this study, the cement was studied further to evaluate its in vitro biological properties (cytocompatibility, platelet activation), anti-infective, and bone regenerative potential in comparison to poly(methyl methacrylate) (PMMA) cement and parenteral therapy in 43 patients (age 5-57 years) with chronic MRSA osteomyelitis by analyzing the results of histopathology, radiographs, magnetic resonance imaging, scanning electron microscopy, and serum drug concentrations for 1 year. The composite cement showed superior cytocompatibility and coagulant activity compared to PMMA cement. Moreover, the results of different postoperative clinical and radiological examinations also proved the supremacy of composite cement over the other treatment modalities in terms of success rate, faster sepsis control and bone regeneration. Low serum antibiotic concentrations and normal serum calcium levels indicate that the calcium-rich composite cement is safe for application in human. Therefore, we conclude that the composite bone cement is a promising candidate for the treatment of chronic osteomyelitis.

Outside-in technique versus inside-out semitendinosus graft harvest technique in ACLR: a randomised control trial.

BACKGROUND: Paraesthesia after hamstring graft harvest is a ubiquitous complication in the early post-operative period, and its correlation with vertical versus horizontal skin incision are well documented. The purpose of the study is to evaluate the incidence and extent/area of sensory loss of saphenous nerve branches occurring with the outside-in (OI) versus inside-out technique (IO) of semitendinosus graft harvest from the sartorius fascia and to determine a better method of graft harvest. METHODS: Sixty patients who underwent isolated semitendinosus graft harvest during anterior cruciate ligament reconstruction (ACLR) between 2016 and 2017. Patients were randomised into two groups depending on the graft harvest technique: 30 in the OI group and 30 in the IO group. The area of sensory loss was mapped on the patients' skin using tactile feedback from the patients at each follow-up (10 days, 1 month, 3 months, 6 months and 1 year). Then, the area of sensory changes for the infrapatellar branch (IPBSN) and sartorial branch (SBSN) of the saphenous nerve, incision length, graft harvest duration, and graft length were analysed statistically between the groups. RESULTS: In groups 1 and 2, 18/30 (60%) and 19/30 (63%) of patients, respectively, developed sensory changes, with no significant difference between the groups (p = 0.79). Isolated SBSN and IPBSN paraesthesia occurred in 2/60 (3%) and 19/60 (32%), respectively. Combined SBSN and IPBSN paraesthesia was present in 16/60 (27%) of patients. There was no significant difference in the area of the sensory deficit between OI and IO groups on the 10th post-operative day or at 1-month, 3-month or 1-year follow-up (p = 0.723, p = 0.308, p = 0.478, p = 0.128, respectively). However, at 6-month follow-up, the area of paraesthesia was significantly higher in the IO group (p = 0.009). The length of incision and duration of graft harvest was higher in the OI group than in the IO group (p = 0.002 and p = 0.007, respectively), and the total length of the graft was greater in the IO group (p = 0.04). CONCLUSION: Incidence is equally distributed, area of iatrogenic saphenous nerve injury gradually decreases, and recovery is seen in the majority of the patients in both graft harvest techniques. IO graft harvesting technique is better in terms of graft harvest time and cosmetics and yields longer graft; however, area of paraesthesia, though not significant, was two-fold higher than the OI technique at 1-year follow-up. CLINICAL RELEVANCE: IO graft harvest technique would enable the surgeon to adopt quicker graft harvest, smaller surgical scar and lengthier graft than the OI technique. LEVEL OF EVIDENCE: Therapeutic randomised controlled prospective study, Level II.

Corrigendum: Corynebacterium glutamicum as an efficient omnivorous microbial host for the bioconversion of lignocellulosic biomass.

[This corrects the article DOI: 10.3389/fbioe.2022.827386.].

Tubercular Osteomyelitis of Pubis with Labial Abscess: A Rare Presentation of a Common Disease.

Introduction: Skeletal tuberculosis (TB) accounts for 10-15% of all cases of extra-pulmonary TB. The involvement of pubis is extremely rare with only 40 cases of pubic bone TB reported in the medical literature. The presentation of the disease with labial abscess is much rarer with only one case reported till now. Case Report: A 23-year-old female presented with symptoms of pain and swelling in the right groin. The patient was evaluated with hematological and radiological investigations and the diagnosis of Tubercular osteomyelitis of pubis with labial abscess was confirmed using AFB staining and culture of the aspirate. The patient was subsequently managed with Anti-tubercular chemotherapy for 18 months and the lesion healed with excellent functional outcome. Conclusion: Tubercular Osteomyelitis of the pubis is a rare disease with varied clinical presentation. Timely diagnosis and anti-tubercular chemotherapy usually result in complete recovery.

Arthroscopic reduction and internal fixation (ARIF) versus open reduction internal fixation (ORIF) to elucidate the difference for tibial side PCL avulsion fixation: a randomized controlled trial (RCT).

PURPOSE: To compare the clinical, radiological outcomes, economic and technical differences for ORIF by cancellous screw fixation versus ARIF by double-tunnel suture fixation for displaced tibial-side PCL avulsion fractures. METHODS: Forty patients with displaced tibial-sided PCL avulsions were operated upon after randomizing them into two groups (20 patients each in the open and arthroscopic group) and followed up prospectively. Assessment included duration of surgery, cost involved, pre- and post-operative functional scores, radiological assessment of union, and posterior laxity using stress radiography and complications. RESULTS: The mean follow-up period was 33 months (27-42) (open group) and 30 months (26-44) (arthroscopic group). The duration of surgery was significantly larger in the arthroscopic group (47.8 ± 17.9 min) as compared to the open group (33.4 ± 10.1 min). The costs involved were significantly higher in the arthroscopic group (p- 0.01). At final follow-up, knee function in the form of IKDC (International Knee Documentation Committee) evaluation (89.9 ± 4.8-open and 89.3 ± 5.9-arthroscopic) and Lysholm scores (94.2 ± 4.1-open and 94.6 ± 4.1-arthroscopic) had improved significantly with the difference (n.s.) between the two groups. The mean posterior tibial displacement was 5.7 ± 1.8 mm in the open group and 6.3 ± 3.1 mm in the arthroscopic group which was (n.s.). There were two non-unions and one popliteal artery injury in the arthroscopic group. CONCLUSION: Both ARIF and ORIF for PCL avulsion fractures yield good clinical and radiological outcomes. However, ORIF was better than ARIF in terms of cost, duration of surgery, and complications like non-union and iatrogenic vascular injury. LEVEL OF EVIDENCE: II.

Do coracohumeral interval and glenoid version play a role in subscapularis tears?

PURPOSE: To study the effect of the coracohumeral interval and orientation of the glenoid for causation of subscapularis tears and literature review for the need of coracoplasty. METHODS: This is a retrospective cohort study of patients who underwent arthroscopic shoulder surgery from January 2013 to December 2017. The coracohumeral interval and orientation of the glenoid in patients with arthroscopically diagnosed subscapularis tears (group A, n = 40) were compared with 2 control groups (group B, n = 38 [intact subscapularis with supraspinatus and infraspinatus cuff tears] and group C, n = 39 [intact rotator cuff]). Group A1 (n = 23) consisted of the isolated subscapularis and combined subscapularis + supraspinatus tears, and group A2 (n = 17) all the 3 rotator cuff tears. The measurements were made on preoperative axial magnetic resonance imaging. Statistical analysis was performed to compare the groups. RESULTS: The mean coracohumeral interval was 8.81 ± 2.69 mm in group A and 10.62 ± 2.21 and 10.39 ± 2.59 mm in control groups B and C, respectively; this difference was statistically significant (P = .002 and .01, respectively). The mean glenoid version in patients with subscapularis tears was -3.7°, whereas the mean version in patients with intact cuff was -3.4°, and this difference was not statistically significant (P = .74). The mean glenoid version was -4.69° ± 4.22° in group A1 and -3.28° ± 4.04° in group B, with no statistically significant difference (P = .07). CONCLUSION: The coracohumeral interval was significantly decreased in patients with subscapularis tears. The glenoid was retroverted in the subscapularis group but was not statistically significant.

Does change in occupancy ratio and fatty infiltration of the supraspinatus influence functional outcome after single-row rotator cuff repair? A magnetic resonance imaging-based study.

INTRODUCTION: The purpose of this study was to analyze the correlation of occupancy ratio (OR) and fatty infiltration (FI) to functional outcome and retear rate following rotator cuff repair by single-row technique. MATERIAL AND METHODS: Retrospectively, all the patients (n = 100) with rotator cuff tear were evaluated preoperatively and postoperatively with functional scores (American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form [ASES], University of California-Los Angeles [UCLA] shoulder score, Constant score) and magnetic resonance imaging (MRI) for OR and FI. Two observers studied the MRI data separately. Statistical analysis was done using SPSS (version 16), paired t test, Pearson correlation, and intraclass correlation coefficients. RESULTS: The mean (± standard deviation) follow-up was 16.24 ± 6.39 months, and the mean age was 56.18 ± 7.5 years. There was a significant increase in muscle atrophy (decreased OR) and FI (P < .01). The mean preoperative and postoperative ORs were 0.57 and 0.51, respectively. However, the mean functional scores improved significantly for ASES (55.78 to 82.09), UCLA (19.44 to 28.47), and Constant score (49.73 to 75.07) (P < .001). There was no significant difference in functional outcome among the different stages of FI (ASES P = .341, UCLA P = .839, Constant P = .376). Seven patients had asymptomatic retear during follow-up, of which 2 patients had grade 3, 4 patients had grade 2, and 1 patient had grade 1 FI, preoperatively. CONCLUSION: Muscle atrophy and FI are irreversible phenomena and continue even after successful repair; however, they do not have a significant influence on the functional outcome at short-term follow-up after cuff repair. Repairing cuff with higher grades of FI can be performed as they achieve significantly improved functional outcomes.

Detection of self-organized criticality behavior in an electronic circuit designed to solve a third order non-linear ODE (NL-ODE) for a damped KdV equation.

In this work, we present an electronic implementation of a damped Korteweg-de Vries equation modeled as a third order nonlinear autonomous ordinary differential equation (jerk equation). The circuit has been realized using operational amplifiers, multipliers, and passive electronic components which provides the time series solution of the equation in agreement with the numerical simulation results. Using nonlinear time series analysis on the acquired waveform data, we have obtained different types of phase space portraits and further analysis reflected long range correlation in the chaotic time series. Important findings include hysteresis induced bifurcation and self-organized criticality behavior in the system which is mentioned in this work.

Video Endoscopic Inguinal Lymphadenectomy vs Open Inguinal Lymphadenectomy for Carcinoma Penis: Expanding Role and Comparison of Outcomes.

OBJECTIVE: To compare differences of morbidity profile, oncological yield, and efficacy between video endoscopic inguinal lymphadenectomy and open inguinal lymphadenectomy cases. MATERIALS AND METHODS: A total of 29 patients with proven squamous cell carcinoma of the penis were selected for inguinal lymphadenectomy from August 2013 to January 2017. Video endoscopic lymphadenectomy was performed on 1 limb and open inguinal lymphadenectomy was performed on the contralateral side. Relevant outcome data such as operative time, complication rate, number of lymph nodes removed, number of positive nodes, and recurrence during the follow-up period were collected, analyzed, and compared. RESULTS: The mean operative time was significantly longer for the video endoscopic inguinal lymphadenectomy group (mean = 162.83 minutes) as compared with the open group (mean = 92.35 minutes). However, the mean numbers of lymph nodes removed were 7.6 in the endoscopic group and 8.3 in the open group. Postoperative complications occurred in 10 limbs (34.48%) in the open group and in 3 limbs (10.34%) in the endoscopic group. In the follow-up period ranging from 7 to 28 (mean 14) months, 2 patients died because of either distant or visceral metastasis. CONCLUSION: The present study clearly outlines the fact that video endoscopic inguinal lymphadenectomy can deliver an equivalent lymph node yield similar to open inguinal lymphadenectomy with significantly less morbidity and is not affected by either the palpability or the number of palpable nodes. Thus, we believe that this minimally invasive technique can provide a prudent alternative for the management of the inguinal region in carcinoma of the penis.

Structural Basis for EarP-Mediated Arginine Glycosylation of Translation Elongation Factor EF-P.

Glycosylation is a universal strategy to posttranslationally modify proteins. The recently discovered arginine rhamnosylation activates the polyproline-specific bacterial translation elongation factor EF-P. EF-P is rhamnosylated on arginine 32 by the glycosyltransferase EarP. However, the enzymatic mechanism remains elusive. In the present study, we solved the crystal structure of EarP from Pseudomonas putida The enzyme is composed of two opposing domains with Rossmann folds, thus constituting a B pattern-type glycosyltransferase (GT-B). While dTDP-ß-l-rhamnose is located within a highly conserved pocket of the C-domain, EarP recognizes the KOW-like N-domain of EF-P. Based on our data, we propose a structural model for arginine glycosylation by EarP. As EarP is essential for pathogenicity in P. aeruginosa, our study provides the basis for targeted inhibitor design.IMPORTANCE The structural and biochemical characterization of the EF-P-specific rhamnosyltransferase EarP not only provides the first molecular insights into arginine glycosylation but also lays the basis for targeted-inhibitor design against Pseudomonas aeruginosa infection.

Saccharopolyspora Species: Laboratory Maintenance and Enhanced Production of Secondary Metabolites.

Saccharopolyspora spp. are aerobic, Gram-positive, non-acid-fast, and non-motile actinomycetes. Various species of the genus Saccharopolyspora have been reported with an ability to produce various bioactive compounds for pharmaceutical and agricultural uses. This unit includes general protocols for the laboratory maintenance of Saccharopolyspora species, including growth in liquid medium, growth on solid agar, long-term storage, and generation of a higher producer strain by mutagenesis. Saccharopolyspora spinosa ATCC 49460 is used as a prototype for explaining the considerations for efficient laboratory maintenance of Saccharopolyspora spp. Saccharopolyspora spinosa is a producer of spinosad, a prominent insecticide with selective activity against various insects. © 2017 by John Wiley & Sons, Inc.

Herboxidiene biosynthesis, production, and structural modifications: prospect for hybrids with related polyketide.

Herboxidiene is a polyketide with a diverse range of activities, including herbicidal, anti-cholesterol, and pre-mRNA splicing inhibitory effects. Thus, production of the compound on the industrial scale is in high demand, and various rational metabolic engineering approaches have been employed to enhance the yield. Directing the precursors and cofactors pool toward the production of polyketide compounds provides a rationale for developing a good host for polyketide production. Due to multiple promising biological activities, the production of a number of herboxidiene derivatives has been attempted in recent years in a search for the key to improve its potency and to introduce new activities. Structural diversification through combinatorial biosynthesis was attempted, utilizing the heterologous expression of substrate-flexible glucosyltransferase (GT) and cytochrome P450 in Streptomyces chromofuscus to generate structurally and functionally diverse derivatives of herboxidiene. The successful attempt confirmed that the strain was amenable to heterologous expression of foreign polyketide synthase (PKS) or post-PKS modification genes, providing the foundation for generating novel or hybrid polyketides.

Genetic evidence for the involvement of glycosyltransferase PdmQ and PdmS in biosynthesis of pradimicin from Actinomadura hibisca.

Pradimicins are potent antifungal antibiotics with effective inhibitory effects against HIV-1. Pradimicin A consists of an unusual dihydrobenzo[α]naphthacenequinone aglycone substituted with a combination of D-alanine and two sugar moieties. Detailed genetic studies revealed most steps in pradimicin A biosynthesis, but the glycosylation mechanism remained inconclusive. The biosynthetic gene cluster of pradimicin A contains two putative glycosyltransferases, pdmQ and pdmS. However, the exact involvement of each gene in biosynthesis and the particular steps required for precise structural modification was unknown. In this study, the exact role of each gene was evaluated by insertional inactivation and complementation studies. Analysis of the metabolite from both of the disruption mutants revealed abolishment of pradimicin A and complementation resulted in the recovery of production. After deletion of pdmQ, pradimicin B was found to accumulate, whereas deletion of pdmS resulted in the accumulation of aglycone of pradimicin. Together, these results suggest that pdmS is responsible for the attachment of thomosamine to form pradimicin B which in turn is glycosylated by pdmQ to form pradimicin A. These results allowed us to deduce the exact order of terminal tailoring by glycosylation and provided insight into the mechanism of pradimicin A biosynthesis.

Structural modification of herboxidiene by substrate-flexible cytochrome P450 and glycosyltransferase.

Herboxidiene is a natural product produced by Streptomyces chromofuscus exhibiting herbicidal activity as well as antitumor properties. Using different substrate-flexible cytochrome P450s and glycosyltransferase, different novel derivatives of herboxidiene were generated with structural modifications by hydroxylation or epoxidation or conjugation with a glucose moiety. Moreover, two isomers of herboxidiene containing extra tetrahydrofuran or tetrahydropyran moiety in addition to the existing tetrahydropyran moiety were characterized. The hydroxylated products for both of these compounds were also isolated and characterized from S. chromofuscus PikC harboring pikC from the pikromycin gene cluster of Streptomyces venezuelae and S. chromofuscus EryF harboring eryF from the erythromycin gene cluster of Saccharopolyspora erythraea. The compounds generated were characterized by high-resolution quadrupole-time-of-flight electrospray ionization mass spectrometry (HR-QTOF-ESI/MS) and (1)H- and (13)C-nuclear magnetic resonance (NMR) analyses. The evaluation of antibacterial activity against three Gram-positive bacteria, Micrococcus luteus, Bacillus subtilis, and Staphylococcus aureus, indicated that modification resulted in a transition from anticancer to antibacterial potency.

Enhanced production of nargenicin A(1) and generation of novel glycosylated derivatives.

Nargenicin A1, an antibacterial polyketide macrolide produced by Nocardia sp. CS682, was enhanced by increasing the pool of precursors using different sources. Furthermore, by using engineered strain Nocardia sp. ACC18 and supplementation of glucose and glycerol, enhancement was ~7.1 fold in comparison to Nocardia sp. CS682 without supplementation of any precursors. The overproduced compound was validated by mass spectrometry and nuclear magnetic resonance analyses. The novel glycosylated derivatives of purified nargenicin A1 were generated by efficient one-pot reaction systems in which the syntheses of uridine diphosphate (UDP)-α-D-glucose and UDP-α-D-2-deoxyglucose were modified and combined with glycosyltransferase (GT) from Bacillus licheniformis. Nargenicin A1 11-O-ß- D-glucopyranoside, nargenicin A1 18-O-ß-D-glucopyranoside, nargenicin A111 18-O-ß-D- diglucopyranoside, and nargenicin 11-O-ß-D-2-deoxyglucopyranoside were generated. Nargenicin A1 11-O-ß-D-glucopyranoside was structurally elucidated by ultra-high performance liquid chromatography-photodiode array (UPLC-PDA) conjugated with high-resolution quantitative time-of-flight-electrospray ionization mass spectroscopy (HR-QTOF ESI-MS/MS), supported by one- and two-dimensional nuclear magnetic resonance studies, whereas other nargenicin A1 glycosides were characterized by UPLC-PDA and HR-QTOF ESI-MS/MS analyses. The overall conversion studies indicated that the one-pot synthesis system is a highly efficient strategy for production of glycosylated derivatives of compounds like macrolides as well. Furthermore, assessment of solubility indicated that there was enhanced solubility in the case of glycoside, although a substantial increase in activity was not observed.

Metabolic engineering of rational screened Saccharopolyspora spinosa for the enhancement of spinosyns A and D production.

Spinosyns A and D are potent ingredient for insect control with exceptional safety to non-target organisms. It consists of a 21-carbon tetracyclic lactone with forosamine and tri-O-methylated rhamnose which are derived from S-adenosylmethionine. Although previous studies have revealed the involvement of metK1 (S-adenosylmethionine synthetase), rmbA (glucose-1-phosphate thymidylyltransferase), and rmbB (TDP-D-glucose-4, 6-dehydratase) in the biosynthesis of spinosad, expression of these genes into rational screened Saccharopolyspora spinosa (S. spinosa MUV) has not been elucidated till date. In the present study, S. spinosa MUV was developed to utilize for metabolic engineering. The yield of spinosyns A and D in S. spinosa MUV was 244 mg L(-1) and 129 mg L(-1), which was 4.88-fold and 4.77-fold higher than that in the wild-type (50 mg L(-1) and 27 mg L(-1)), respectively. To achieve the better production; positive regulator metK1-sp, rmbA and rmbB genes from Streptomyces peucetius, were expressed and co-expressed in S. spinosa MUV under the control of strong ermE* promoter, using an integration vector pSET152 and expression vector pIBR25, respectively. Herewith, the genetically engineered strain of S. spinosa MUV, produce spinosyns A and D up to 372/217 mg L(-1) that is 7.44/8.03-fold greater than that of wild type. This result demonstrates the use of metabolic engineering on rationally developed high producing natural variants for the production.

Switching antibiotics production on and off in actinomycetes by an IclR family transcriptional regulator from Streptomyces peucetius ATCC 27952.

Doxorubicin, produced by Streptomyces peucetius ATCC 27952, is tightly regulated by dnrO, dnrN, and dnrI regulators. Genome mining of S. peucetius revealed the presence of the IclR (doxR) type family of transcription regulator mediating the signal-dependent expression of operons at the nonribosomal peptide synthetase gene cluster. Overexpression of doxR in native strain strongly repressed the drug production. Furthermore, it also had a negative effect on the regulatory system of doxorubicin, wherein the transcript of dnrI was reduced to the maximum level in comparision with the other two. Interestingly, the overexpression of the same gene also had strong inhibitory effects on the production of actinorhodin (blue pigment) and undecylprodigiosin (red pigment) in Streptomyces coelicolor M145, herboxidiene production in Streptomyces chromofuscus ATCC 49982, and spinosyn production in Saccharopolyspora spinosa NRRL 18395, respectively. Moreover, DoxR exhibited pleiotropic effects on the production of blue and red pigments in S. coelicolor when grown in different agar media, wherein the production of blue pigment was inhibited in R2YE medium and the red pigment was inhibited in YEME medium. However, the production of both blue and red pigments from S. coelicolor harboring doxR was halted in ISP2 medium, whereas S. coelicolor produced both pigmented antibiotics in the same plate. These consequences demonstrate that the on and off production of these antibiotics was not due to salt stress or media compositions, but was selectively controlled in actinomycetes.