scholarly journals Two Components of a velvet-Like Complex Control Hyphal Morphogenesis, Conidiophore Development, and Penicillin Biosynthesis in Penicillium chrysogenum

2010 ◽  
Vol 9 (8) ◽  
pp. 1236-1250 ◽  
Author(s):  
Birgit Hoff ◽  
Jens Kamerewerd ◽  
Claudia Sigl ◽  
Rudolf Mitterbauer ◽  
Ivo Zadra ◽  
...  
Keyword(s):  
Penicillium Chrysogenum ◽  
High Performance ◽  
Strain Improvement ◽  
Bimolecular Fluorescence Complementation ◽  
Northern Hybridization ◽  
Penicillin Biosynthesis ◽  
Improvement Program ◽  
Content Type ◽  
Pellet Formation ◽  
Severe Impairment

ABSTRACT Penicillium chrysogenum is the industrial producer of the antibiotic penicillin, whose biosynthetic regulation is barely understood. Here, we provide a functional analysis of two major homologues of the velvet complex in P. chrysogenum, which we have named P. chrysogenum velA (PcvelA) and PclaeA. Data from array analysis using a ΔPcvelA deletion strain indicate a significant role of PcVelA on the expression of biosynthesis and developmental genes, including PclaeA. Northern hybridization and high-performance liquid chromatography quantifications of penicillin titers clearly show that both PcVelA and PcLaeA play a major role in penicillin biosynthesis in a producer strain that underwent several rounds of UV mutagenesis during a strain improvement program. Both regulators are further involved in different developmental processes. While PcvelA deletion leads to light-independent conidial formation, dichotomous branching of hyphae, and pellet formation in shaking cultures, a ΔPclaeA strain shows a severe impairment in conidiophore formation under both light and dark conditions. Bimolecular fluorescence complementation assays provide evidence for a velvet-like complex in P. chrysogenum, with structurally conserved components that have distinct developmental roles, illustrating the functional plasticity of these regulators in genera other than Aspergillus.

scholarly journals Members of the Penicillium chrysogenum Velvet Complex Play Functionally Opposing Roles in the Regulation of Penicillin Biosynthesis and Conidiation

2012 ◽  
Vol 12 (2) ◽  
pp. 299-310 ◽  
Author(s):  
Katarina Kopke ◽  
Birgit Hoff ◽  
Sandra Bloemendal ◽  
Alexandra Katschorowski ◽  
Jens Kamerewerd ◽  
...  
Keyword(s):  
Penicillium Chrysogenum ◽  
Strain Improvement ◽  
Interaction Network ◽  
Inhibitory Effect ◽  
Bimolecular Fluorescence Complementation ◽  
Penicillin Biosynthesis ◽  
Double Knockout ◽  
Content Type ◽  
Improvement Programs ◽  
Velvet Complex

ABSTRACT A velvet multisubunit complex was recently detected in the filamentous fungus Penicillium chrysogenum , the major industrial producer of the β-lactam antibiotic penicillin. Core components of this complex are P. chrysogenum VelA (PcVelA) and PcLaeA, which regulate secondary metabolite production, hyphal morphology, conidiation, and pellet formation. Here we describe the characterization of PcVelB, PcVelC, and PcVosA as novel subunits of this velvet complex. Using yeast two-hybrid analysis and bimolecular fluorescence complementation (BiFC), we demonstrate that all velvet proteins are part of an interaction network. Functional analyses using single- and double-knockout strains clearly indicate that velvet subunits have opposing roles in the regulation of penicillin biosynthesis and light-dependent conidiation. PcVelC, together with PcVelA and PcLaeA, activates penicillin biosynthesis, while PcVelB represses this process. In contrast, PcVelB and PcVosA promote conidiation, while PcVelC has an inhibitory effect. Our genetic analyses further show that light-dependent spore formation depends not only on PcVelA but also on PcVelB and PcVosA. The results provided here contribute to our fundamental understanding of the function of velvet subunits as part of a regulatory network mediating signals responsible for morphology and secondary metabolism and will be instrumental in generating mutants with newly derived properties that are relevant to strain improvement programs.

scholarly journals Identification of a Polyketide Synthase Involved in Sorbicillin Biosynthesis by Penicillium chrysogenum

2016 ◽  
Vol 82 (13) ◽  
pp. 3971-3978 ◽  
Author(s):  
Oleksandr Salo ◽  
Fernando Guzmán-Chávez ◽  
Marco I. Ries ◽  
Peter P. Lankhorst ◽  
Roel A. L. Bovenberg ◽  
...  
Keyword(s):  
Penicillium Chrysogenum ◽  
Polyketide Synthase ◽  
Strain Improvement ◽  
Antimicrobial Activities ◽  
Pathway Engineering ◽  
Improvement Program ◽  
Content Type ◽  
Industrial Strains ◽  
Rapid Purification ◽  
Yellow Pigments

ABSTRACTSecondary metabolism inPenicillium chrysogenumwas intensively subjected to classical strain improvement (CSI), the resulting industrial strains producing high levels of β-lactams. During this process, the production of yellow pigments, including sorbicillinoids, was eliminated as part of a strategy to enable the rapid purification of β-lactams. Here we report the identification of the polyketide synthase (PKS) gene essential for sorbicillinoid biosynthesis inP. chrysogenum. We demonstrate that the production of polyketide precursors like sorbicillinol and dihydrosorbicillinol as well as their derivatives bisorbicillinoids requires the function of a highly reducing PKS encoded by the genePc21g05080(pks13). This gene belongs to the cluster that was mutated and transcriptionally silenced during the strain improvement program. Using an improved β-lactam-producing strain, repair of the mutation inpks13led to the restoration of sorbicillinoid production. This now enables genetic studies on the mechanism of sorbicillinoid biosynthesis inP. chrysogenumand opens new perspectives for pathway engineering.IMPORTANCESorbicillinoids are secondary metabolites with antiviral, anti-inflammatory, and antimicrobial activities produced by filamentous fungi. This study identified the gene cluster responsible for sorbicillinoid formation inPenicillium chrysogenum, which now allows engineering of this diverse group of compounds.

scholarly journals Increased Penicillin Production in Penicillium chrysogenum Production Strains via Balanced Overexpression of Isopenicillin N Acyltransferase

2012 ◽  
Vol 78 (19) ◽  
pp. 7107-7113 ◽  
Author(s):  
Stefan S. Weber ◽  
Fabiola Polli ◽  
Rémon Boer ◽  
Roel A. L. Bovenberg ◽  
Arnold J. M. Driessen
Keyword(s):  
Penicillium Chrysogenum ◽  
Phenylacetic Acid ◽  
Strain Improvement ◽  
Single Copy ◽  
Limiting Factor ◽  
Penicillin Biosynthesis ◽  
Penicillin Production ◽  
Content Type ◽  
Coa Ligase ◽  
Isopenicillin N

ABSTRACTIntense classical strain improvement has yielded industrialPenicillium chrysogenumstrains that produce high titers of penicillin. These strains contain multiple copies of the penicillin biosynthesis cluster encoding the three key enzymes: δ-(l-α-aminoadipyl)-l-cysteinyl-d-valine synthetase (ACVS), isopenicillin N synthase (IPNS), and isopenicillin N acyltransferase (IAT). The phenylacetic acid coenzyme A (CoA) ligase (PCL) gene encoding the enzyme responsible for the activation of the side chain precursor phenylacetic acid is localized elsewhere in the genome in a single copy. Since the protein level of IAT already saturates at low cluster copy numbers, IAT might catalyze a limiting step in high-yielding strains. Here, we show that penicillin production in high-yielding strains can be further improved by the overexpression of IAT while at very high levels of IAT the precursor 6-aminopenicillic acid (6-APA) accumulates. Overproduction of PCL only marginally stimulates penicillin production. These data demonstrate that in high-yielding strains IAT is the limiting factor and that this limitation can be alleviated by a balanced overproduction of this enzyme.

scholarly journals Characterization of an Autoinducer of Penicillin Biosynthesis in Penicillium chrysogenum

2011 ◽  
Vol 77 (16) ◽  
pp. 5688-5696 ◽  
Author(s):  
Jorge Martín ◽  
Carlos García-Estrada ◽  
Ángel Rumbero ◽  
Eliseo Recio ◽  
Silvia M. Albillos ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Penicillium Chrysogenum ◽  
Molecular Mechanisms ◽  
Biological Activities ◽  
Northern Analysis ◽  
Penicillin Biosynthesis ◽  
Control Of Gene Expression ◽  
Content Type ◽  
Direct Testing

ABSTRACTFilamentous fungi produce an impressive variety of secondary metabolites; many of them have important biological activities. The biosynthesis of these secondary metabolites is frequently induced by plant-derived external elicitors and appears to also be regulated by internal inducers, which may work in a way similar to that of bacterial autoinducers. The biosynthesis of penicillin inPenicillium chrysogenumis an excellent model for studying the molecular mechanisms of control of gene expression due to a good knowledge of the biochemistry and molecular genetics of β-lactam antibiotics and to the availability of its genome sequence and proteome. In this work, we first developed a plate bioassay that allows direct testing of inducers of penicillin biosynthesis using single colonies ofP. chrysogenum. Using this bioassay, we have found an inducer substance in the conditioned culture broths ofP. chrysogenumandAcremonium chrysogenum. No inducing effect was exerted by γ-butyrolactones, jasmonic acid, or the penicillin precursor δ-(l-α-aminoadipyl)-l-cysteinyl-d-valine. The conditioned broth induced penicillin biosynthesis and transcription of thepcbAB,pcbC, andpenDEgenes when added at inoculation time, but its effect was smaller if added at 12 h and it had no effect when added at 24 h, as shown by Northern analysis andlacZreporter studies. The inducer molecule was purified and identified by mass spectrometry (MS) and nuclear magnetic resonance (NMR) as 1,3-diaminopropane. Addition of pure 1,3-diaminopropane stimulated the production of penicillin by about 100% compared to results for the control cultures. Genes for the biosynthesis of 1,3-diaminopropane have been identified in theP. chrysogenumgenome.

scholarly journals Genomic mutational analysis of the impact of the classical strain improvement program on β–lactam producing Penicillium chrysogenum

BMC Genomics ◽  
2015 ◽  
Vol 16 (1) ◽  
Author(s):  
Oleksandr V. Salo ◽  
Marco Ries ◽  
Marnix H. Medema ◽  
Peter P. Lankhorst ◽  
Rob J. Vreeken ◽  
...  
Keyword(s):  
Penicillium Chrysogenum ◽  
Mutational Analysis ◽  
Strain Improvement ◽  
Improvement Program ◽  
Classical Strain ◽  
The Impact

Pilot Plant Study on Microaerobic Self-Granulated Sludge Process (Multi-Stage Reversing Flow Bioreactor: MRB)

1991 ◽  
Vol 23 (4-6) ◽  
pp. 973-980 ◽  
Author(s):  
M. Takahashi ◽  
S. Kyosai
Keyword(s):  
Pilot Plant ◽  
High Performance ◽  
Anaerobic Bacteria ◽  
Domestic Wastewater ◽  
Public Works ◽  
Symbiotic Interaction ◽  
Sulfate Reducing ◽  
Pellet Formation ◽  
Multi Stage ◽  
Domestic Wastewater Treatment

A Multi-stage Reversing flow Bioreactor (MRB) was developed by the Public Works Research Institute in 1986. It utilizes the symbiotic interaction between anaerobic bacteria (sulfate reducing bacteria) and microaerobic bacteria (Beggiatoa=filamentous sulfur oxidizing bacteria) for self-granulated pellet formation. A MRB Pilot plant for domestic wastewater treatment (design capacity was 225 m3/day) was constructed in 1988. After several modifications of the initial design, stable pellet formation and high performance were achieved. This paper describes the results of the pilot plant operation.

scholarly journals Rough diamonds in emerging markets: legacy, competitiveness, and sustained high performance

2019 ◽  
Vol 26 (3) ◽  
pp. 363-386
Author(s):  
Seung Ho Park ◽  
Gerardo R. Ungson
Keyword(s):  
Human Capital ◽  
Emerging Markets ◽  
High Performance ◽  
Core Competencies ◽  
Market Potential ◽  
Government Support ◽  
Screening Tests ◽  
Institutional Voids ◽  
Content Type ◽  
Over Time

Purpose The purpose of this paper is to uncover the underlying drivers of sustained high performing companies based on a field study of 127 companies in Brazilian, Russian, Indian and Chinese (BRIC) and Association of Southeast Asian Nations (ASEAN) emerging markets. Understanding these companies provides a complementary way of appraising the growth, development and transformation of emerging markets. The authors synthesize the findings in an overarching framework that covers six strategies for building and sustaining legacy that leads to the succession of intergenerational wealth over time: overcoming institutional voids, inclusive markets, deepening localization, nurturing government support, building core competencies and harnessing human capital. The authors relate these strategies to different levels of development using Prahalad and Hart’s BOP framework. Design/methodology/approach This study examines the underlying drivers of sustained high-performance companies based on field studies from an initial set of 105,260 BRIC companies and close to 500 companies in ASEAN. The methods employed four screening tests to arrive at a selection of the highest-performing firms: 70 firms in the BRIC nations and 58 firms from ASEAN. Following the selection, the authors constructed cases using primary interviews and secondary data, with the assistance of Ernst & Young and with academic colleagues in Manila. These studies were originally conducted in two separate time periods and reported accordingly. This paper synthesizes the findings of these two studies to arrive at an extended integrative framework. Findings From the cases, the authors examine six strategies for building and sustaining legacy that lead to high performance over time: overcoming institutional voids, creating inclusive markets, deepening localization, nurturing government support, building core competencies and harnessing human capital. To address the evolving state of institutional voids in these countries, the authors employ similar methods to hypothesize the placement of these strategies in the context of the world economic pyramid, initially formulated as the “bottom of the pyramid” framework. Originality/value This paper synthesizes and extends the authors’ previous works by proposing the concept of legacy to describe the emergence and succession of local exemplary firms in emerging markets. This study aims to complement extant measures of nation-growth based primarily on GDP. The paper also extends the literature on institutional voids in shifting the focus from the mix of voids to their evolving state. Altogether, the paper provides a complementary narrative on assessing the market potential of emerging markets by adopting several categories of performance.

scholarly journals In VitroActivities of Daptomycin-, Vancomycin-, and Teicoplanin-Loaded Polymethylmethacrylate against Methicillin-Susceptible, Methicillin-Resistant, and Vancomycin-Intermediate Strains of Staphylococcus aureus

2011 ◽  
Vol 55 (12) ◽  
pp. 5480-5484 ◽  
Author(s):  
Yuhan Chang ◽  
Wen-Chien Chen ◽  
Pang-Hsin Hsieh ◽  
Dave W. Chen ◽  
Mel S. Lee ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
High Performance ◽  
Low Dose ◽  
Antibacterial Activities ◽  
High Dose ◽  
Bone Cements ◽  
Antibacterial Effects ◽  
Methicillin Resistant ◽  
Content Type

ABSTRACTThe objective of this study was to evaluate the antibacterial effects of polymethylmethacrylate (PMMA) bone cements loaded with daptomycin, vancomycin, and teicoplanin against methicillin-susceptibleStaphylococcus aureus(MSSA), methicillin-resistantStaphylococcus aureus(MRSA), and vancomycin-intermediateStaphylococcus aureus(VISA) strains. Standardized cement specimens made from 40 g PMMA loaded with 1 g (low-dose), 4 g (middle-dose) or 8 g (high-dose) antibiotics were tested for elution characteristics and antibacterial activities. The patterns of release of antibiotics from the cement specimens were evaluated usingin vitrobroth elution assay with high-performance liquid chromatography. The activities of broth elution fluid against differentStaphylococcus aureusstrains (MSSA, MRSA, and VISA) were then determined. The antibacterial activities of all the tested antibiotics were maintained after being mixed with PMMA. The cements loaded with higher dosages of antibiotics showed longer elution periods. Regardless of the antibiotic loading dose, the teicoplanin-loaded cements showed better elution efficacy and provided longer inhibitory periods against MSSA, MRSA, and VISA than cements loaded with the same dose of vancomycin or daptomycin. Regarding the choice of antibiotics for cement loading in the treatment ofStaphylococcus aureusinfection, teicoplanin was superior in terms of antibacterial effects.

scholarly journals Overproduction of Ristomycin A by Activation of a Silent Gene Cluster in Amycolatopsis japonicum MG417-CF17

2014 ◽  
Vol 58 (10) ◽  
pp. 6185-6196 ◽  
Author(s):  
Marius Spohn ◽  
Norbert Kirchner ◽  
Andreas Kulik ◽  
Angelika Jochim ◽  
Felix Wolf ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gene Cluster ◽  
High Performance ◽  
Pathogenic Bacteria ◽  
Genome Mining ◽  
Gene Clusters ◽  
Von Willebrand Disease ◽  
Biosynthesis Gene Cluster ◽  
Content Type ◽  
Bioinformatic Tools

ABSTRACTThe emergence of antibiotic-resistant pathogenic bacteria within the last decades is one reason for the urgent need for new antibacterial agents. A strategy to discover new anti-infective compounds is the evaluation of the genetic capacity of secondary metabolite producers and the activation of cryptic gene clusters (genome mining). One genus known for its potential to synthesize medically important products isAmycolatopsis. However,Amycolatopsis japonicumdoes not produce an antibiotic under standard laboratory conditions. In contrast to mostAmycolatopsisstrains,A. japonicumis genetically tractable with different methods. In order to activate a possible silent glycopeptide cluster, we introduced a gene encoding the transcriptional activator of balhimycin biosynthesis, thebbrgene fromAmycolatopsis balhimycina(bbrAba), intoA. japonicum. This resulted in the production of an antibiotically active compound. Following whole-genome sequencing ofA. japonicum, 29 cryptic gene clusters were identified by genome mining. One of these gene clusters is a putative glycopeptide biosynthesis gene cluster. Using bioinformatic tools, ristomycin (syn. ristocetin), a type III glycopeptide, which has antibacterial activity and which is used for the diagnosis of von Willebrand disease and Bernard-Soulier syndrome, was deduced as a possible product of the gene cluster. Chemical analyses by high-performance liquid chromatography and mass spectrometry (HPLC-MS), tandem mass spectrometry (MS/MS), and nuclear magnetic resonance (NMR) spectroscopy confirmed thein silicoprediction that the recombinantA. japonicum/pRM4-bbrAbasynthesizes ristomycin A.

Developing junior doctors as leaders of service improvement

2014 ◽  
Vol 27 (4) ◽  
pp. 316-329 ◽  
Author(s):  
Jason Micallef ◽  
Brodene Straw
Keyword(s):  
Leadership Development ◽  
Medical Staff ◽  
Medical Service ◽  
Health Service Delivery ◽  
Public Healthcare ◽  
Service Improvement ◽  
Junior Doctors ◽  
Program Outcomes ◽  
Improvement Program ◽  
Content Type

Purpose – This paper aims to provide an overview of the design and initial outcomes of a leadership and service improvement program for junior medical staff. Design/methodology/approach – This paper describes the rationale, initial set-up, structure, program outcomes and future directions of the Medical Service Improvement Program for junior doctors. This program is a recent initiative of the Western Australian public healthcare system. Findings – The Medical Service Improvement Program illustrates a successful approach to developing junior doctors to lead improvements in health service delivery. The program has resulted in tangible personal outcomes for participants, in addition to important organisational outcomes. Practical implications – This paper provides an evidence-based structured approach to developing the leadership abilities of junior medical staff. It provides practical information on the design of the leadership program that aligns the participant learning outcomes to postgraduate medical competencies. The program has demonstrated clear service outcomes, confirming that junior medical staff is both capable and committed to leading service improvement and reform. Originality/value – This paper provides clear evidence for the benefits of providing dedicated non-clinical time for junior medical staff to lead quality and improvement initiatives. This case study will assist hospital administrators, postgraduate education units and those involved in designing and administering clinical leadership development programs.

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