scholarly journals Identification and Characterization of a Tetramethylpyrazine Catabolic Pathway in Rhodococcus jostii TMP1

2013 ◽  
Vol 79 (12) ◽  
pp. 3649-3657 ◽  
Author(s):  
Simonas Kutanovas ◽  
Jonita Stankeviciute ◽  
Gintaras Urbelis ◽  
Daiva Tauraite ◽  
Rasa Rutkiene ◽  
...  
Keyword(s):  
Expression Profiles ◽  
Bacterial Degradation ◽  
Ring Cleavage ◽  
Published Data ◽  
Catabolic Pathway ◽  
Genome Database ◽  
Content Type ◽  
Intermediate Metabolites ◽  
Inducible Protein ◽  
Rhodococcus Jostii

ABSTRACTAt present, there are no published data on catabolic pathways ofN-heterocyclic compounds, in which all carbon atoms carry a substituent. We identified the genetic locus and characterized key reactions in the aerobic degradation of tetramethylpyrazine inRhodococcus jostiistrain TMP1. By comparing protein expression profiles, we identified a tetramethylpyrazine-inducible protein of 40 kDa and determined its identity by tandem mass spectrometry (MS-MS)de novosequencing. Searches against anR. jostiiTMP1 genome database allowed the identification of the tetramethylpyrazine-inducible protein-coding gene. The tetramethylpyrazine-inducible gene was located within a 13-kb genome cluster, denominated the tetramethylpyrazine degradation (tpd) locus, that encoded eight proteins involved in tetramethylpyrazine catabolism. The genes from this cluster were cloned and transferred into tetramethylpyrazine-nondegradingRhodococcus erythropolisstrain SQ1. This allowed us to verify the function of thetpdlocus, to isolate intermediate metabolites, and to reconstruct the catabolic pathway of tetramethylpyrazine. We report that the degradation of tetramethylpyrazine is a multistep process that includes initial oxidative aromatic-ring cleavage by tetramethylpyrazine oxygenase, TpdAB; subsequent hydrolysis by (Z)-N,N′-(but-2-ene-2,3-diyl)diacetamide hydrolase, TpdC; and further intermediate metabolite reduction by aminoalcohol dehydrogenase, TpdE. Thus, the genes responsible for bacterial degradation of pyrazines have been identified, and intermediate metabolites of tetramethylpyrazine degradation have been isolated for the first time.

scholarly journals Biodegradation of the Allelopathic Chemical Pterostilbene by a Sphingobium sp. Strain from the Peanut Rhizosphere

2018 ◽  
Vol 85 (5) ◽  
Author(s):  
Ri-Qing Yu ◽  
Zohre Kurt ◽  
Fei He ◽  
Jim C. Spain
Keyword(s):  
Pathogenic Fungi ◽  
Bacterial Degradation ◽  
Ecological Role ◽  
Microbial Infection ◽  
Catabolic Pathway ◽  
Content Type ◽  
Dead End ◽  
Initial Cleavage ◽  
Bacterial Interference

ABSTRACT Many plants produce allelopathic chemicals, such as stilbenes, to inhibit pathogenic fungi. The degradation of allelopathic compounds by bacteria associated with the plants would limit their effectiveness, but little is known about the extent of biodegradation or the bacteria involved. Screening of tissues and rhizosphere of peanut (Arachis hypogaea) plants revealed substantial enrichment of bacteria able to grow on resveratrol and pterostilbene, the most common stilbenes produced by the plants. Investigation of the catabolic pathway in Sphingobium sp. strain JS1018, isolated from the rhizosphere, indicated that the initial cleavage of pterostilbene was catalyzed by a carotenoid cleavage oxygenase (CCO), which led to the transient accumulation of 4-hydroxybenzaldehyde and 3,5-dimethoxybenzaldehyde. 4-Hydroxybenzaldehyde was subsequently used for the growth of the isolate, while 3,5-dimethoxybenzaldehyde was further converted to a dead-end metabolite with a molecular weight of 414 (C24H31O6). The gene that encodes the initial oxygenase was identified in the genome of strain JS1018, and its function was confirmed by heterologous expression in Escherichia coli. This study reveals the biodegradation pathway of pterostilbene by plant-associated bacteria. The prevalence of such bacteria in the rhizosphere and plant tissues suggests a potential role of bacterial interference in plant allelopathy. IMPORTANCE Pterostilbene, an analog of resveratrol, is a stilbene allelochemical produced by plants to inhibit microbial infection. As a potent antioxidant, pterostilbene acts more effectively than resveratrol as an antifungal agent. Bacterial degradation of this plant natural product would affect the allelopathic efficacy and fate of pterostilbene and thus its ecological role. This study explores the isolation and abundance of bacteria that degrade resveratrol and pterostilbene in peanut tissues and rhizosphere, the catabolic pathway for pterostilbene, and the molecular basis for the initial cleavage of pterostilbene. If plant allelopathy is an important process in agriculture and management of invasive plants, the ecological role of bacteria that degrade the allelopathic chemicals must be equally important.

scholarly journals The Two-Component Monooxygenase MeaXY Initiates the Downstream Pathway of Chloroacetanilide Herbicide Catabolism in Sphingomonads

2017 ◽  
Vol 83 (7) ◽  
Author(s):  
Minggen Cheng ◽  
Qiang Meng ◽  
Youjian Yang ◽  
Cuiwei Chu ◽  
Qing Chen ◽  
...  
Keyword(s):  
Ring Cleavage ◽  
Monooxygenase System ◽  
Biochemical Pathway ◽  
Catabolic Pathway ◽  
Aniline Derivative ◽  
Content Type ◽  
The Past ◽  
Chloroacetanilide Herbicides ◽  
Two Component ◽  
Key Genes

ABSTRACT Due to the extensive use of chloroacetanilide herbicides over the past 60 years, bacteria have evolved catabolic pathways to mineralize these compounds. In the upstream catabolic pathway, chloroacetanilide herbicides are transformed into the two common metabolites 2-methyl-6-ethylaniline (MEA) and 2,6-diethylaniline (DEA) through N-dealkylation and amide hydrolysis. The pathway downstream of MEA is initiated by the hydroxylation of aromatic rings, followed by its conversion to a substrate for ring cleavage after several steps. Most of the key genes in the pathway have been identified. However, the genes involved in the initial hydroxylation step of MEA are still unknown. As a special aniline derivative, MEA cannot be transformed by the aniline dioxygenases that have been characterized. Sphingobium baderi DE-13 can completely degrade MEA and use it as a sole carbon source for growth. In this work, an MEA degradation-deficient mutant of S. baderi DE-13 was isolated. MEA catabolism genes were predicted through comparative genomic analysis. The results of genetic complementation and heterologous expression demonstrated that the products of meaX and meaY are responsible for the initial step of MEA degradation in S. baderi DE-13. MeaXY is a two-component flavoprotein monooxygenase system that catalyzes the hydroxylation of MEA and DEA using NADH and flavin mononucleotide (FMN) as cofactors. Nuclear magnetic resonance (NMR) analysis confirmed that MeaXY hydroxylates MEA and DEA at the para-position. Transcription of meaX was enhanced remarkably upon induction of MEA or DEA in S. baderi DE-13. Additionally, meaX and meaY were highly conserved among other MEA-degrading sphingomonads. This study fills a gap in our knowledge of the biochemical pathway that carries out mineralization of chloroacetanilide herbicides in sphingomonads. IMPORTANCE Much attention has been paid to the environmental fate of chloroacetanilide herbicides used for the past 60 years. Microbial degradation is considered an important mechanism in the degradation of these compounds. Bacterial degradation of chloroacetanilide herbicides has been investigated in many recent studies. Pure cultures or consortia able to mineralize these herbicides have been obtained. The catabolic pathway has been proposed, and most key genes involved have been identified. However, the genes responsible for the initiation step (from MEA to hydroxylated MEA or from DEA to hydroxylated DEA) of the downstream pathway have not been reported. The present study demonstrates that a two-component flavin-dependent monooxygenase system, MeaXY, catalyzes the para-hydroxylation of MEA or DEA in sphingomonads. Therefore, this work finds a missing link in the biochemical pathway that carries out the mineralization of chloroacetanilide herbicides in sphingomonads. Additionally, the results expand our understanding of the degradation of a special kind of aniline derivative.

scholarly journals Role of IncP-1β Plasmids pWDL7::rfpand pNB8c in Chloroaniline Catabolism as Determined by Genomic and Functional Analyses

2011 ◽  
Vol 78 (3) ◽  
pp. 828-838 ◽  
Author(s):  
J. E. Król ◽  
J. T. Penrod ◽  
H. McCaslin ◽  
L. M. Rogers ◽  
H. Yano ◽  
...  
Keyword(s):  
Single Copy ◽  
Degradation Pathway ◽  
Bacterial Degradation ◽  
Ring Cleavage ◽  
Close Relative ◽  
Broad Host Range ◽  
Content Type ◽  
Aromatic Ring Cleavage ◽  
Functional Analyses

ABSTRACTBroad-host-range catabolic plasmids play an important role in bacterial degradation of man-made compounds. To gain insight into the role of these plasmids in chloroaniline degradation, we determined the first complete nucleotide sequences of an IncP-1 chloroaniline degradation plasmid, pWDL7::rfpand its close relative pNB8c, as well as the expression pattern, function, and bioaugmentation potential of the putative 3-chloroaniline (3-CA) oxidation genes. Based on phylogenetic analysis of backbone proteins, both plasmids are members of a distinct clade within the IncP-1β subgroup. The plasmids are almost identical, but whereas pWDL7::rfpcarries a duplicate inverted catabolic transposon, Tn6063, containing a putative 3-CA oxidation gene cluster,dcaQTA1A2BR, pNB8c contains only a single copy of the transposon. No genes for an aromatic ring cleavage pathway were detected on either plasmid, suggesting that only the upper 3-CA degradation pathway was present. ThedcaA1A2Bgene products expressed from a high-copy-number vector were shown to convert 3-CA to 4-chlorocatechol inEscherichia coli. Slight differences in thedcapromoter region between the plasmids and lack of induction of transcription of the pNB8cdcagenes by 3-CA may explain previous findings that pNB8C does not confer 3-CA transformation. Bioaugmentation of activated sludge with pWDL7::rfpaccelerated removal of 3-CA, but only in the presence of an additional carbon source. Successful bioaugmentation requires complementation of the upper pathway genes with chlorocatechol cleavage genes in indigenous bacteria. The genome sequences of these plasmids thus help explain the molecular basis of their catabolic activities.

scholarly journals Molecular Mechanism and Genetic Determinants of Buprofezin Degradation

2017 ◽  
Vol 83 (18) ◽  
Author(s):  
Xueting Chen ◽  
Junbin Ji ◽  
Leizhen Zhao ◽  
Jiguo Qiu ◽  
Chen Dai ◽  
...  
Keyword(s):  
Molecular Mechanism ◽  
Benzene Ring ◽  
Microbial Degradation ◽  
Natural Environment ◽  
Heterocyclic Ring ◽  
Ring Cleavage ◽  
Genetic Determinants ◽  
Catabolic Pathway ◽  
Content Type ◽  
Aromatic Ring Cleavage

ABSTRACT Buprofezin is a widely used insect growth regulator whose residue has been frequently detected in the environment, posing a threat to aquatic organisms and nontarget insects. Microorganisms play an important role in the degradation of buprofezin in the natural environment. However, the relevant catabolic pathway has not been fully characterized, and the molecular mechanism of catabolism is still completely unknown. Rhodococcus qingshengii YL-1 can utilize buprofezin as a sole source of carbon and energy for growth. In this study, the upstream catabolic pathway in strain YL-1 was identified using tandem mass spectrometry. Buprofezin is composed of a benzene ring and a heterocyclic ring. The degradation is initiated by the dihydroxylation of the benzene ring and continues via dehydrogenation, aromatic ring cleavage, breaking of an amide bond, and the release of the heterocyclic ring 2-tert-butylimino-3-isopropyl-1,3,5-thiadiazinan-4-one (2-BI). A buprofezin degradation-deficient mutant strain YL-0 was isolated. A comparative genomic analysis combined with gene deletion and complementation experiments revealed that the gene cluster bfzBA3A4A1A2C is responsible for the upstream catabolic pathway of buprofezin. The bfzA3A4A1A2 cluster encodes a novel Rieske nonheme iron oxygenase (RHO) system that is responsible for the dihydroxylation of buprofezin at the benzene ring; bfzB is involved in dehydrogenation, and bfzC is in charge of benzene ring cleavage. Furthermore, the products of bfzBA3A4A1A2C can also catalyze dihydroxylation, dehydrogenation, and aromatic ring cleavage of biphenyl, flavanone, flavone, and bifenthrin. In addition, a transcriptional study revealed that bfzBA3A4A1A2C is organized in one transcriptional unit that is constitutively expressed in strain YL-1. IMPORTANCE There is an increasing concern about the residue and environmental fate of buprofezin. Microbial metabolism is an important mechanism responsible for the buprofezin degradation in the natural environment. However, the molecular mechanism and genetic determinants of microbial degradation of buprofezin have not been well identified. This work revealed that gene cluster bfzBA3A4A1A2C is responsible for the upstream catabolic pathway of buprofezin in Rhodococcus qingshengii YL-1. The products of bfzBA3A4A1A2C could also degrade bifenthrin, a widely used pyrethroid insecticide. These findings enhance our understanding of the microbial degradation mechanism of buprofezin and benefit the application of strain YL-1 and bfzBA3A4A1A2C in the bioremediation of buprofezin contamination.

scholarly journals Isolation of the (+)-Pinoresinol-MineralizingPseudomonassp. Strain SG-MS2 and Elucidation of Its Catabolic Pathway

2017 ◽  
Vol 84 (4) ◽  
Author(s):  
Madhura Shettigar ◽  
Sahil Balotra ◽  
David Cahill ◽  
Andrew C. Warden ◽  
Michael J. Lacey ◽  
...  
Keyword(s):  
Shikimic Acid ◽  
Conclusive Evidence ◽  
Quinone Methide ◽  
Ring Cleavage ◽  
Catabolic Pathway ◽  
Content Type ◽  
Reductive Transformation ◽  
Benzylic Hydroxylation ◽  
Acid Pathway ◽  
Dead Plant

ABSTRACTPinoresinol is a dimer of two β-β′-linked coniferyl alcohol molecules. It is both a plant defense molecule synthesized through the shikimic acid pathway and a representative of several β-β-linked dimers produced during the microbial degradation of lignin in dead plant material. Until now, little has been known about the bacterial catabolism of such dimers. Here we report the isolation of the efficient (+)-pinoresinol-mineralizingPseudomonassp. strain SG-MS2 and its catabolic pathway. Degradation of pinoresinol in this strain is inducible and proceeds via a novel oxidative route, which is in contrast to the previously reported reductive transformation by other bacteria. Based on enzyme assays and bacterial growth, cell suspension, and resting cell studies, we provide conclusive evidence that pinoresinol degradation in strain SG-MS2 is initiated by benzylic hydroxylation, generating a hemiketal via a quinone methide intermediate, which is then hydrated at the benzylic carbon by water. The hemiketal, which stays in equilibrium with the corresponding keto alcohol, undergoes an aryl-alkyl cleavage to generate a lactone and 2-methoxyhydroquinone. While the fate of 2-methoxyhydroquinone is not investigated further, it is assumed to be assimilated by ring cleavage. The lactone is further metabolized via two routes, namely, lactone ring cleavage and benzylic hydroxylation via a quinone methide intermediate, as described above. The resulting hemiketal again exists in equilibrium with a keto alcohol. Our evidence suggests that both routes of lactone metabolism lead to vanillin and vanillic acid, which we show can then be mineralized by strain SG-MS2.IMPORTANCEThe oxidative catabolism of (+)-pinoresinol degradation elucidated here is fundamentally different from the reductive cometabolism reported for two previously characterized bacteria. Our findings open up new opportunities to use lignin for the biosynthesis of vanillin, a key flavoring agent in foods, beverages, and pharmaceuticals, as well as various new lactones. Our work also has implications for the study of new pinoresinol metabolites in human health. The enterodiol and enterolactone produced through reductive transformation of pinoresinol by gut microbes have already been associated with decreased risks of cancer and cardiovascular diseases. The metabolites from oxidative metabolism we find here also deserve attention in this respect.

scholarly journals Analysis of thexplAB-Containing Gene Cluster Involved in the Bacterial Degradation of the Explosive Hexahydro-1,3,5-Trinitro-1,3,5-Triazine

2014 ◽  
Vol 80 (21) ◽  
pp. 6601-6610 ◽  
Author(s):  
Chun Shiong Chong ◽  
Dana Khdr Sabir ◽  
Astrid Lorenz ◽  
Cyril Bontemps ◽  
Peter Andeer ◽  
...  
Keyword(s):  
Environmental Protection Agency ◽  
Contaminated Soils ◽  
Genomic Island ◽  
Bacterial Degradation ◽  
Ring Cleavage ◽  
Anaerobic Conditions ◽  
Content Type ◽  
Redox Partner ◽  
Repeated Use ◽  
Aerobic And Anaerobic

ABSTRACTRepeated use of the explosive compound hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) on military land has resulted in significant soil and groundwater pollution. Rates of degradation of RDX in the environment are low, and accumulated RDX, which the U.S. Environmental Protection Agency has determined is a possible human carcinogen, is now threatening drinking water supplies. RDX-degrading microorganisms have been isolated from RDX-contaminated land; however, despite the presence of these species in contaminated soils, RDX pollution persists. To further understand this problem, we studied RDX-degrading species belonging to four different genera (Rhodococcus,Microbacterium,Gordonia, andWilliamsia) isolated from geographically distinct locations and established that thexplAandxplB(xplAB) genes, which encode a cytochrome P450 and a flavodoxin redox partner, respectively, are nearly identical in all these species. Together, thexplABsystem catalyzes the reductive denitration of RDX and subsequent ring cleavage under aerobic and anaerobic conditions. In addition toxplAB, theRhodococcusspecies studied here share a 14-kb region flankingxplAB; thus, it appears likely that the RDX-metabolizing ability was transferred as a genomic island within a transposable element. The conservation and transfer ofxplAB-flanking genes suggest a role in RDX metabolism. We therefore independently knocked out genes within this cluster in the RDX-degrading speciesRhodococcus rhodochrous11Y. Analysis of the resulting mutants revealed that XplA is essential for RDX degradation and that XplB is not the sole contributor of reducing equivalents to XplA. While XplA expression is induced under nitrogen-limiting conditions and further enhanced by the presence of RDX, MarR is not regulated by RDX.

scholarly journals Estrogen Degraders and Estrogen Degradation Pathway Identified in an Activated Sludge

2018 ◽  
Vol 84 (10) ◽  
Author(s):  
Yi-Lung Chen ◽  
Han-Yi Fu ◽  
Tzong-Huei Lee ◽  
Chao-Jen Shih ◽  
Lina Huang ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment Plant ◽  
Degradation Pathway ◽  
Bacterial Degradation ◽  
Ring Cleavage ◽  
Main Process ◽  
Content Type ◽  
Degrading Bacteria

ABSTRACTThe environmental release and fate of estrogens are becoming an increasing public concern. Bacterial degradation has been considered the main process for eliminating estrogens from wastewater treatment plants. Various bacterial isolates are reportedly capable of aerobic estrogen degradation, and several estrogen degradation pathways have been proposed in proteobacteria and actinobacteria. However, the ecophysiological relevance of estrogen-degrading bacteria in the environment is unclear. In this study, we investigated the estrogen degradation pathway and corresponding degraders in activated sludge collected from the Dihua Sewage Treatment Plant, Taipei, Taiwan. Cultivation-dependent and cultivation-independent methods were used to assess estrogen biodegradation in the collected activated sludge. Estrogen metabolite profile analysis revealed the production of pyridinestrone acid and two A/B-ring cleavage products in activated sludge incubated with estrone (1 mM), which are characteristic of the 4,5-secopathway. PCR-based functional assays detected sequences closely related to alphaproteobacterialoecC, a key gene of the 4,5-secopathway. Metagenomic analysis suggested thatNovosphingobiumspp. are major estrogen degraders in estrone-amended activated sludge.Novosphingobiumsp. strain SLCC, an estrone-degrading alphaproteobacterium, was isolated from the examined activated sludge. The general physiology and metabolism of this strain were characterized. Pyridinestrone acid and the A/B-ring cleavage products were detected in estrone-grown strain SLCC cultures. The production of pyridinestrone acid was also observed during the aerobic incubation of strain SLCC with 3.7 nM (1 μg/liter) estrone. This concentration is close to that detected in many natural and engineered aquatic ecosystems. The presented data suggest the ecophysiological relevance ofNovosphingobiumspp. in activated sludge.IMPORTANCEEstrogens, which persistently contaminate surface water worldwide, have been classified as endocrine disruptors and human carcinogens. We contribute new knowledge on the major estrogen biodegradation pathway and estrogen degraders in wastewater treatment plants. This study considerably advances the understanding of environmental estrogen biodegradation, which is instrumental for the efficient elimination of these hazardous pollutants. Moreover, this study substantially improves the understanding of microbial estrogen degradation in the environment.

scholarly journals Biological Impact of a Large-Scale Genomic Inversion That Grossly Disrupts the Relative Positions of the Origin and Terminus Loci of theStreptococcus pyogenesChromosome

2019 ◽  
Vol 201 (17) ◽  
Author(s):  
Dragutin J. Savic ◽  
Scott V. Nguyen ◽  
Kimberly McCullor ◽  
W. Michael McShan
Keyword(s):  
Dna Sequences ◽  
Parental Strain ◽  
Large Scale ◽  
Galleria Mellonella ◽  
Acute Infection ◽  
Relative Length ◽  
Published Data ◽  
Rich Medium ◽  
Content Type

ABSTRACTA large-scale genomic inversion encompassing 0.79 Mb of the 1.816-Mb-longStreptococcus pyogenesserotype M49 strain NZ131 chromosome spontaneously occurs in a minor subpopulation of cells, and in this report genetic selection was used to obtain a stable lineage with this chromosomal rearrangement. This inversion, which drastically displaces theorisite relative to the terminus, changes the relative length of the replication arms so that one replichore is approximately 0.41 Mb while the other is about 1.40 Mb in length. Genomic reversion to the original chromosome constellation is not observed in PCR-monitored analyses after 180 generations of growth in rich medium. Compared to the parental strain, the inversion surprisingly demonstrates a nearly identical growth pattern in the first phase of the exponential phase, but differences do occur when resources in the medium become limited. When cultured separately in rich medium during prolonged stationary phase or in an experimental acute infection animal model (Galleria mellonella), the parental strain and the invertant have equivalent survival rates. However, when they are coincubated together, bothin vitroandin vivo, the survival of the invertant declines relative to the level for the parental strain. The accompanying aspect of the study suggests that inversions taking place nearoriCalways happen to secure the linkage oforiCto DNA sequences responsible for chromosome partition. The biological relevance of large-scale inversions is also discussed.IMPORTANCEBased on our previous work, we created to our knowledge the largest asymmetric inversion, covering 43.5% of theS. pyogenesgenome. In spite of a drastic replacement of origin of replication and the unbalanced size of replichores (1.4 Mb versus 0.41 Mb), the invertant, when not challenged with its progenitor, showed impressive vitality for growthin vitroand in pathogenesis assays. The mutant supports the existing idea that slightly deleterious mutations can provide the setting for secondary adaptive changes. Furthermore, comparative analysis of the mutant with previously published data strongly indicates that even large genomic rearrangements survive provided that the integrity of theoriCand the chromosome partition cluster is preserved.

Estimating performance from capabilities in business process improvement

2016 ◽  
Vol 22 (6) ◽  
pp. 1099-1117 ◽  
Author(s):  
Boyd A. Nicholds ◽  
John P.T. Mo
Keyword(s):  
Process Improvement ◽  
Business Process ◽  
Expected Improvement ◽  
Management Decision ◽  
Published Data ◽  
Performance Gain ◽  
Data Set ◽  
Business Process Improvement ◽  
Improvement Project ◽  
Content Type

Purpose The research indicates there is a positive link between the improvement capability of an organisation and the intensity of effort applied to a business process improvement (BPI) project or initiative. While a degree of stochastic variation in applied effort to any particular improvement project may be expected there is a clear need to quantify the causal relationship, to assist management decision, and to enhance the chance of achieving and sustaining the expected improvement targets. The paper aims to discuss these issues. Design/methodology/approach The paper presents a method to obtain the function that estimates the range of applicable effort an organisation can expect to be able to apply based on their current improvement capability. The method used analysed published data as well as regression analysis of new data points obtained from completed process improvement projects. Findings The level of effort available to be applied to a process improvement project can be expressed as a regression function expressing the possible range of achievable BPI performance within 90 per cent confidence limits. Research limitations/implications The data set applied by this research is limited due to constraints during the research project. A more accurate function can be obtained with more industry data. Practical implications When the described function is combined with a separate non-linear function of performance gain vs effort a model of performance gain for a process improvement project as a function of organisational improvement capability is obtained. The probability of success in achieving performance targets may be estimated for a process improvement project. Originality/value The method developed in this research is novel and unique and has the potential to be applied to assessing an organisation’s capability to manage change.

scholarly journals Genetic Investigation of the Catabolic Pathway for Degradation of Abietane Diterpenoids by Pseudomonas abietaniphilaBKME-9

2000 ◽  
Vol 182 (13) ◽  
pp. 3784-3793 ◽  
Author(s):  
Vincent J. J. Martin ◽  
William W. Mohn
Keyword(s):  
Gene Cluster ◽  
Sequence Similarity ◽  
Open Reading Frames ◽  
Ring Cleavage ◽  
Catabolic Pathway ◽  
Transcriptional Fusion ◽  
Abietane Diterpenoids ◽  
Genes Encoding ◽  
Dna Fragment ◽  
Reading Frames

ABSTRACT We have cloned and sequenced the dit gene cluster encoding enzymes of the catabolic pathway for abietane diterpenoid degradation by Pseudomonas abietaniphila BKME-9. Thedit gene cluster is located on a 16.7-kb DNA fragment containing 13 complete open reading frames (ORFs) and 1 partial ORF. The genes ditA1A2A3 encode the α and β subunits and the ferredoxin of the dioxygenase which hydroxylates 7-oxodehydroabietic acid to 7-oxo-11,12-dihydroxy-8,13-abietadien acid. The dioxygenase mutant strain BKME-941 (ditA1::Tn5) did not grow on nonaromatic abietanes, and transformed palustric and abietic acids to 7-oxodehydroabietic acid in cell suspension assays. Thus, nonaromatic abietanes are aromatized prior to further degradation. Catechol 2,3-dioxygenase activity of xylEtranscriptional fusion strains showed induction of ditA1and ditA3 by abietic, dehydroabietic, and 7-oxodehydroabietic acids, which support the growth of strain BKME-9, as well as by isopimaric and 12,14-dichlorodehydroabietic acids, which are diterpenoids that do not support the growth of strain BKME-9. In addition to the aromatic-ring-hydroxylating dioxygenase genes, thedit cluster includes ditC, encoding an extradiol ring cleavage dioxygenase, and ditR, encoding an IclR-type transcriptional regulator. Although ditR is not strictly required for the growth of strain BKME-9 on abietanes, aditR::Kmr mutation in aditA3::xylE reporter strain demonstrated that it encodes an inducer-dependent transcriptional activator of ditA3. An ORF with sequence similarity to genes encoding permeases (ditE) is linked with genes involved in abietane degradation.

Sign in / Sign up

Export Citation Format

Share Document