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Hansen DL, Christophersen C, Fonnes S, Rosenberg J. Implementation of robot-assisted groin hernia repair diminishes the prospects of young surgeons' training: a nationwide register-based cohort study. Hernia 2022; 26:1653-1658. [PMID: 36201067 DOI: 10.1007/s10029-022-02691-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 09/20/2022] [Indexed: 11/30/2022]
Abstract
PURPOSE Robot-assisted groin hernia repair is becoming more popular in recent years but may remove operations from surgical trainees. We aimed to investigate the educational level of the surgeons who performed robot-assisted groin hernia repair and the rate of supervision and compare this to open and laparoscopic groin hernia repair. METHODS This register-based study was reported according to the RECORD statement and used linked data from the Danish Hernia Database and the Danish Patient Safety Authority's Online Register. We included surgeons that performed robot-assisted, laparoscopic, and/or open groin hernia repairs performed between January 1, 2015, and June 15, 2021 in Denmark. RESULTS A total of 916 surgeons performing 43,856 groin hernia repairs were included in this study. Surgical specialists performed 98% of the robot-assisted groin hernia repairs, 89% of the laparoscopic repairs (p < 0.0001), and 54% of the Lichtenstein repairs (p < 0.0001). Only 5% of the robot-assisted groin hernia repairs were supervised compared with 11% of the laparoscopic repairs (p < 0.0001) and 28% of the open repairs (p < 0.0001). CONCLUSION Almost all groin hernia repairs performed with the robot-assisted technique were performed by surgeons specialized in general surgery. The proportions of surgeons specialized in surgery were higher for robot-assisted operations compared with laparoscopic or open groin hernia surgery. Thus, our data suggest a lack of involvement of surgeons in training, and this diminishes the educational potential in the pool of groin hernia operations by the use of robot-assisted repairs.
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Gram-Hanssen A, Christophersen C, Rosenberg J. Results from patient-reported outcome measures are inconsistently reported in inguinal hernia trials: a systematic review. Hernia 2022; 26:687-699. [PMID: 34480660 DOI: 10.1007/s10029-021-02492-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Accepted: 08/26/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE To evaluate the use, results, and reporting of patient-reported outcome measures specific to patients undergoing inguinal hernia repair. METHODS A systematic review was performed and reported according to the PRISMA 2020 statement. A protocol was registered at PROSPERO (CRD42021243468). Systematic searches were performed in PubMed and EMBASE. We only included randomized controlled trials that involved postoperative administration of a hernia-specific patient-reported outcome measure. Risk of bias was evaluated with the Cochrane risk of bias-tool 2.0. RESULTS Twenty trials and four different instruments were included: the Carolinas Comfort Scale (nine studies), Activities Assessment Scale (six studies), Inguinal Pain Questionnaire (seven studies), and Surgical Pain Scales (one study). Included trials used patient-reported outcome measures and compared either different surgical approaches (11 studies), types of mesh/fixation (seven studies), or types of anesthesia/analgesia (two studies). Results were reported using several different methods including means, medians, or proportions of either overall results, results from subscales, or results from single questionnaire items. Seven of the 20 included studies specified a patient-reported outcome measure as a primary outcome and provided clear reporting of sample size calculation. CONCLUSION Reporting of results from patient-reported outcome measures in inguinal hernia research was characterized by heterogeneity. The results were reported using several different methods, which impedes proper evidence synthesis. Only half of the included studies applied a patient-reported outcome measure as primary outcome. Ultimately, the heterogeneity in outcome reporting is an important methodological problem obstructing the full utilization of patient-reported outcome measures in inguinal hernia research.
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Christophersen C, Baker JJ, Fonnes S, Andresen K, Rosenberg J. Lower reoperation rates after open and laparoscopic groin hernia repair when performed by high-volume surgeons: a nationwide register-based study. Hernia 2021; 25:1189-1197. [PMID: 33835325 DOI: 10.1007/s10029-021-02400-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/17/2021] [Indexed: 11/30/2022]
Abstract
PURPOSE Previous studies have shown a correlation between surgeons with high annual volume and better outcomes after various surgical procedures. However, the preexisting literature regarding groin hernia repair and annual surgeon volume is limited. The aim was to investigate how annual surgeon volume affected the reoperation rates for recurrence after primary groin hernia repair. METHODS This nationwide cohort study was based on data from the Danish Hernia Database and the Danish Patient Safety Authority's Online Register. Patients ≥ 18 years undergoing laparoscopic or Lichtenstein primary groin hernia repair between November 2011 and January 2020 were included. Annual surgeon volume was divided into five categories: ≤ 10, 11-25, 26-50, 51-100, and > 100 cases/year. RESULTS We included 25,262 groin hernia repairs performed in 23,088 patients. The risk of reoperation for recurrence after Lichtenstein repair was significantly higher for the volume categories of ≤ 10 (HR 4.02), 11-25 (HR 3.64), 26-50 (HR 3.93), or 51-100 (HR 4.30), compared with the > 100 category. The risk of reoperation for recurrence after laparoscopic repair was significantly increased for the volume categories of ≤ 10 (HR 1.89), 11-25 (HR 2.08), 26-50 (HR 1.80), and 51-100 (HR 1.58) compared with the > 100 category. CONCLUSION The risk of reoperation for recurrence was significantly higher after Lichtenstein and laparoscopic repairs performed by surgeons with < 100 cases/year compared with > 100 cases/year. This indicates that higher surgeon volume minimizes the risk of reoperation for recurrence after groin hernia repair.
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Gram-Hanssen A, Jessen ML, Christophersen C, Zetner D, Rosenberg J. Trends in the use of patient-reported outcome measures for inguinal hernia repair: a quantitative systematic review. Hernia 2020; 25:1111-1120. [PMID: 33074397 DOI: 10.1007/s10029-020-02322-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2020] [Accepted: 10/07/2020] [Indexed: 01/01/2023]
Abstract
PURPOSE To quantitatively assess the use of patient-reported outcome measures in studies involving patients undergoing inguinal hernia repair. METHODS We performed a systematic literature search in Medline and EMBASE. We included all studies published between 2000 and 2019 that involved > 5 patients receiving inguinal hernia repair and evaluated a postoperative patient-reported outcome measure. Studies were stratified in 5-year intervals. We extracted data on which patient-reported outcome measure was used, its time of administration, study design, and the size and composition of the study population. Data were presented using descriptive statistics. RESULTS We included 929 studies that covered 81 different patient-reported outcome measures. Of these, the Short-Form 36 was the most commonly used generic instrument (14%), the Carolinas Comfort Scale was the most commonly used hernia-specific instrument (5%), and the Visual Analogue Scale was the most commonly used domain-specific instrument (70%). There was a proportional decrease in the use of generic instruments, from 24% of studies in 2000-2004 to only 14% of studies in 2015-2019. Conversely, there was an increase in the use of hernia-specific instruments, from 0% in 2000-2004 to 18% in 2015-2019. CONCLUSIONS There is heterogeneity in the use of patient-reported outcome measures in the field of inguinal hernia research. The use of hernia-specific instruments is increasing, the use of generic instruments is decreasing, and the use of domain-specific instruments remains consistently high. This study serves as a repository of all available patient-reported outcome measures relevant to patients undergoing inguinal hernia repair.
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Belova LM, Dahlberg ED, Riazanova A, Mulders JJL, Christophersen C, Eckert J. Rapid electron beam assisted patterning of pure cobalt at elevated temperatures via seeded growth. NANOTECHNOLOGY 2011; 22:145305. [PMID: 21368354 DOI: 10.1088/0957-4484/22/14/145305] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new method of direct, rapid nano- to micro-scale patterning of high purity cobalt is presented. The method utilizes a combination of electron beam induced deposition (EBID) and seeded growth at elevated temperatures below the temperature of spontaneous thermal decomposition. Dicobalt octacarbonyl Co₂(CO)₈ is used as the precursor and carbon as a seed layer. Seeded deposition is carried out in the substrate temperature range from 55 to 75 °C. Deposition yield is significantly higher than conventional EBID and magnetotransport measurements indicate that resistivity, 22 µΩ cm, and saturation magnetization, 1.55 T, are much closer to the corresponding values for bulk Co than those for standard EBID.
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Christophersen C, Wright AD, Vercoe P. Examining diversity of free-living methanogens
and those associated with protozoa in the rumen. JOURNAL OF ANIMAL AND FEED SCIENCES 2004. [DOI: 10.22358/jafs/73736/2004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Murillo JI, Encarnación-Dimayuga R, Malmstrøm J, Christophersen C, Franzblau SG. Antimycobacterial flavones from Haplopappus sonorensis. Fitoterapia 2003; 74:226-30. [PMID: 12727485 DOI: 10.1016/s0367-326x(03)00033-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Crude extracts of Haplopappus sonorensis (A. Gray) S.F. Blake (Asteraceae), showed activity against Mycobacterium tuberculosis H(37)Rv. By assay-guided fractionation, 5-hydroxy-3,7,4'-trimethoxyflavone (1). 5,7-dihydroxy-3,4'-dimethoxyflavone (2). and 5,4'-dihydroxy-3,7-dimethoxyflavone (3). were identified as the antimycobacterial principles. Compound 2 was the most active compound.
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Nielsen TH, Sørensen D, Tobiasen C, Andersen JB, Christophersen C, Givskov M, Sørensen J. Antibiotic and biosurfactant properties of cyclic lipopeptides produced by fluorescent Pseudomonas spp. from the sugar beet rhizosphere. Appl Environ Microbiol 2002; 68:3416-23. [PMID: 12089023 PMCID: PMC126818 DOI: 10.1128/aem.68.7.3416-3423.2002] [Citation(s) in RCA: 163] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cyclic lipopeptides (CLPs) with antibiotic and biosurfactant properties are produced by a number of soil bacteria, including fluorescent Pseudomonas spp. To provide new and efficient strains for the biological control of root-pathogenic fungi in agricultural crops, we isolated approximately 600 fluorescent Pseudomonas spp. from two different agricultural soils by using three different growth media. CLP production was observed in a large proportion of the strains (approximately 60%) inhabiting the sandy soil, compared to a low proportion (approximately 6%) in the loamy soil. Chemical structure analysis revealed that all CLPs could be clustered into two major groups, each consisting of four subgroups. The two major groups varied primarily in the number of amino acids in the cyclic peptide moiety, while each of the subgroups could be differentiated by substitutions of specific amino acids in the peptide moiety. Production of specific CLPs could be affiliated with Pseudomonas fluorescens strain groups belonging to biotype I, V, or VI. In vitro analysis using both purified CLPs and whole-cell P. fluorescens preparations demonstrated that all CLPs exhibited strong biosurfactant properties and that some also had antibiotic properties towards root-pathogenic microfungi. The CLP-producing P. fluorescens strains provide a useful resource for selection of biological control agents, whether a single strain or a consortium of strains was used to maximize the synergistic effect of multiple antagonistic traits in the inoculum.
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Christophersen C, Ottersen T, Seff K, Treppendahl S. Oxidation of thioureas in protic media. Structures of Hector's, Dost's, and Hugershoff's bases. J Am Chem Soc 2002. [DOI: 10.1021/ja00851a036] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Holm A, Schaumburg K, Dahlberg N, Christophersen C, Snyder JP. Alkylation of multisite aromatic heterocycles. 1,2,3,4-Thiatriazoles. J Org Chem 2002. [DOI: 10.1021/jo00892a010] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Romero Ariza M, Larsen TO, Petersen BO, Duus JØ, Christophersen C, Barrero AF. A novel alkaloid serantrypinone and the spiro azaphilone daldinin D from Penicillium thymicola. JOURNAL OF NATURAL PRODUCTS 2001; 64:1590-1592. [PMID: 11754624 DOI: 10.1021/np0101550] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The novel quinazoline metabolite serantrypinone (1) has been isolated from an isolate of the microfungus Penicillium thymicola together with daldinin D (2), a new peracetylated spiro azaphilone derivative. The structures of 1 and 2 were elucidated by analysis of spectroscopic data, including 2D NMR, and comparison with literature data.
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Sørensen D, Nielsen TH, Christophersen C, Sørensen J, Gajhede M. Cyclic lipoundecapeptide amphisin from Pseudomonas sp. strain DSS73. Acta Crystallogr C 2001; 57:1123-4. [PMID: 11588392 DOI: 10.1107/s0108270101010782] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2001] [Accepted: 06/28/2001] [Indexed: 11/10/2022] Open
Abstract
The crystal structure of the lipoundecapeptide amphisin, presented here as the tetrahydrate, C(66)H(114)N(12)O(20).4H(2)O, originating from non-ribosomal biosynthesis by Pseudomonas sp. strain DSS73, has been solved to a resolution of 0.65 A. The primary structure of amphisin is beta-hydroxydecanoyl-D-Leu-D-Asp-D-allo-Thr-D-Leu-D-Leu-D-Ser-L-Leu-D-Gln-L-Leu-L-Ile-L-Asp (Leu is leucine, Asp is aspartic acid, Thr is threonine, Ser is serine, Gln is glutamine and Ile is isoleucine). The peptide is a lactone, linking Thr4 O(gamma) to the C-terminal. The stereochemistry of the beta-hydroxy acid is R. The peptide is a close analogue of the cyclic lipopeptides tensin and pholipeptin produced by Pseudomonas fluorescens. The structure of amphisin is mainly helical (3(10)-helix), with the cyclic peptide wrapping around a hydrogen-bonded water molecule. This lipopeptide is amphiphilic and has biosurfactant and antifungal properties.
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Nielsen TH, Thrane C, Christophersen C, Anthoni U, Sørensen J. Structure, production characteristics and fungal antagonism of tensin - a new antifungal cyclic lipopeptide from Pseudomonas fluorescens strain 96.578. J Appl Microbiol 2000; 89:992-1001. [PMID: 11123472 DOI: 10.1046/j.1365-2672.2000.01201.x] [Citation(s) in RCA: 125] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIM To study the antagonistic activity by Pseudomonas fluorescens strain 96.578 on the plant pathogenic fungus Rhizoctonia solani. METHODS AND RESULTS Strain 96.578 produced a new cyclic lipopeptide, tensin. High tensin production per cell was detected in liquid media with glucose, mannitol or glutamate as growth substrate while fructose, sucrose and asparagine supported low production. Tensin production was nearly constant in media with different initial C levels, while low initial N contents reduced production. When applied to sugar beet seeds, strain 96.578 produced tensin during seed germination. When challenged with strain 96.578 or purified tensin, Rhizoctonia solani reduced radial mycelium extension but increased branching and rosette formation. CONCLUSION The antagonistic activity of strain 96.578 towards Rhizoctonia solani was caused by tensin. SIGNIFICANCE AND IMPACT OF THE STUDY When coated onto sugar beet seeds, tensin production by strain 96.578 could be of significant importance for inhibition of mycelial growth and seed infection by Rhizoctonia solani.
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Holst PB, Christophersen C, Engvild KC. In vivo incorporation of radioactive 36Cl, a method for monitoring chloro compounds in biological material. J Chromatogr A 2000; 903:267-70. [PMID: 11153951 DOI: 10.1016/s0021-9673(00)00893-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A new method for fast and easy monitoring of the presence, isolation, and separation of natural chloro compounds in plants is described. The method relies on the in vivo incorporation of radioactive 36Cl and new enhancement methods in autoradiographic technology. The method allows the time of exposure to be limited to 4 days and is thus suitable for routine purposes.
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Encarnación RD, Sandoval E, Malmstrøm J, Christophersen C. Calafianin, a bromotyrosine derivative from the marine sponge Aplysina gerardogreeni. JOURNAL OF NATURAL PRODUCTS 2000; 63:874-875. [PMID: 10869226 DOI: 10.1021/np990489d] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Calafianin (1) and two known compounds, aerothionin and (3, 5-dibromo-2-hydroxy-4-methoxyphenyl)acetic acid, were isolated from the marine sponge Aplysina gerardogreeni. The structure of 1 was determined by NMR analysis and mass spectrometry.
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Malmstrøm J, Christophersen C, Frisvad JC. Secondary metabolites characteristic of Penicillium citrinum, Penicillium steckii and related species. PHYTOCHEMISTRY 2000; 54:301-309. [PMID: 10870185 DOI: 10.1016/s0031-9422(00)00106-0] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Two new carboxylic acids, tanzawaic acid E (1) and F (2) in addition to the unknown benzopyran 3,7-dimethyl-1,8-dihydroxy-6-methoxy-isochroman (3), and the known mycotoxin 3,7-dimethyl-8-hydroxy-6-methoxyisochroman (4) were produced by a marine-derived strain of Penicillium steckii isolated from an unidentified tunicate. The carboxylic acids and the benzopyran were identified on the basis of mass spectrometry, and one and two dimensional NMR spectroscopic techniques. The structures 1 and 2 resemble tanzawaic acid A-D, previously isolated from Penicillium citrinum. Screening of isolates of species related to P. citrinum and P. steckii showed that P. citrinum (25 isolates) consistently produced citrinin and tanzawaic acid A, P. steckii (18 isolates) produced isochroman toxins (except 2) and tanzawaic acid E, P. sizovae consistently produced tanzawaic acid A, P. corylophilum (10 isolates) produced citreoisocoumarinol and P. sumatrense (15 isolates) always produced curvularin.
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Rahbaek L, Frisvad JC, Christophersen C. An amendment of Aspergillus section Candidi based on chemotaxonomical evidence. PHYTOCHEMISTRY 2000; 53:581-586. [PMID: 10724184 DOI: 10.1016/s0031-9422(99)00596-8] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A novel 2,2'-epoxy-terphenyllin, candidusin C, in addition to the well known secondary metabolites terphenyllin, 3-hydroxyterpenyllin and chlorflavonin, has been isolated from the chemically unexplored fungus Aspergillus campestris. The latter three are known secondary metabolites from Aspergillus candidus and therefore a large number of Aspergilli were screened for production of these compounds to see whether they could be regarded as chemotaxonomical indicators of section membership in the monotypic Aspergillus section Candidi. The results indicated that A. campestris and A. taichungensis should be placed in Candidi and this was further confirmed by morphological and physiological similarities. Three species outside the section Candidi produced candidusin related secondary metabolites: Aspergillus arenarius, A. ellipticus and Penicillium raistrickii. Chlorflavonin, however, was only found in section Candidi.
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Henriksen A, Anthoni U, Nielsen TH, Sørensen J, Christophersen C, Gajhede M. Cyclic lipoundecapeptide tensin from Pseudomonas fluorescens strain 96.578. Acta Crystallogr C 2000; 56 ( Pt 1):113-5. [PMID: 10710691 DOI: 10.1107/s0108270199013414] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/1999] [Accepted: 10/19/1999] [Indexed: 11/10/2022] Open
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Christophersen C, Crescente O, Frisvad JC, Gram L, Nielsen J, Nielsen PH, Rahbaek L. Antibacterial activity of marine-derived fungi. Mycopathologia 1999; 143:135-8. [PMID: 10409050 DOI: 10.1023/a:1006961500325] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
A total of 227 marine isolates of ubiquitous fungi were cultivated on different media and the secondary metabolite content of the extracts (ethyl acetate/chloroform/methanol 3:2:1) characterized by HPLC. The fungi were secured from animals, plants and sediments of Venezuelan waters (0-10 m) including mangroves and lagoonal areas. The extracts were tested for antibacterial activity. A total of 7 were active towards Vibrio parahaemolyticus and 55 towards Staphylococcus aureus, representing 18 different fungal species from 8 ascomycetous genera. For 61 strains of Penicillium citrinum antibacterial activity correlated well with content of secondary metabolites as measured by HPLC. Thirteen isolates of Penicillium steckii produced very similar profiles of secondary metabolites and 6 of these had activity against either V. parahaemolyticus or S. aureus or both.
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Nielsen TH, Christophersen C, Anthoni U, Sørensen J. Viscosinamide, a new cyclic depsipeptide with surfactant and antifungal properties produced by Pseudomonas fluorescens DR54. J Appl Microbiol 1999; 87:80-90. [PMID: 10432590 DOI: 10.1046/j.1365-2672.1999.00798.x] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Pseudomonas fluorescens DR54 showed antagonistic properties against plant pathogenic Pythium ultimum and Rhizoctonia solani both in vitro and in planta. Antifungal activity was extractable from spent growth media, and fractionation by semi-preparative HPLC resulted in isolation of an active compound, which was identified as a new bacterial cyclic lipodepsipeptide, viscosinamide, using 1D and 2D 1H-, 13C-NMR and mass spectrometry. The new antibiotic has biosurfactant properties but differs from the known biosurfactant, viscosin, by containing glutamine rather than glutamate at the amino acid position 2 (AA2). No viscosin production was observed, however, when Ps. fluorescens DR54 was cultured in media enriched with glutamate. In vitro tests showed that purified viscosinamide also reduced fungal growth and aerial mycelium development of both P. ultimum and R. solani. Viscosinamide production by Ps. fluorescens DR54 was tightly coupled to cell proliferation in the batch cultures, as the viscosinamide produced per cell mass unit approached a constant value. In batch cultures with variable initial C, N or P nutrient levels, there were no indications of elevated viscosinamide production during starvation or maintenance of the cultures in stationary phase. Analysis of cellular fractions and spent growth media showed that a major fraction of the viscosinamide produced remained bound to the cell membrane of Ps. fluorescens DR54. The isolation, determination of structure and production characteristics of the new compound with both biosurfactant and antibiotic properties have promising perspectives for the application of Ps. fluorescens DR54 in biological control.
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Lindum PW, Anthoni U, Christophersen C, Eberl L, Molin S, Givskov M. N-Acyl-L-homoserine lactone autoinducers control production of an extracellular lipopeptide biosurfactant required for swarming motility of Serratia liquefaciens MG1. J Bacteriol 1998; 180:6384-8. [PMID: 9829950 PMCID: PMC107727 DOI: 10.1128/jb.180.23.6384-6388.1998] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
A nonswarming Serratia liquefaciens mutant deficient in serrawettin W2 production was constructed by transposon mutagenesis. Sequence homology indicated that insertion had occurred in gene swrA, which encodes a putative peptide synthetase. Expression of swrA is controlled by quorum sensing.
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Larsen TO, Frydenvang K, Frisvad JC, Christophersen C. UV-Guided isolation of alantrypinone, a novel Penicillium alkaloid. JOURNAL OF NATURAL PRODUCTS 1998; 61:1154-1157. [PMID: 9748389 DOI: 10.1021/np980056v] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Fumiquinazoline F (1) and alantrypinone (2) have been isolated as the two major metabolites of Penicillium thymicola. The structure of 2, which contains a new ring structure, was elucidated by analysis of spectroscopic data including 2D NMR. The absolute configuration of 2 was established by a single-crystal X-ray diffraction study.
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Hjorther AB, Christophersen C, Hausen BM, Menné T. Occupational allergic contact dermatitis from carnosol, a naturally-occurring compound present in rosemary. Contact Dermatitis 1997; 37:99-100. [PMID: 9330813 DOI: 10.1111/j.1600-0536.1997.tb00311.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A 56-year-old man, working in a food processing factory, developed contact dermatitis of his hands, forearms, and face after the introduction of a new herb extract (Rosmanox) made from the leaves of rosemary (Rosmarinus officinalis). He reacted to carnosol, the main constituent of Rosmanox. 226 controls were negative. To our knowledge, this is the 1st reported case of contact dermatitis from carnosol.
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Encarnación R, Murillo JI, Nielsen J, Christophersen C. Neothyoside B, a triterpenoid diglycoside from the Pacific sea cucumber Neothyone gibbosa. ACTA CHEMICA SCANDINAVICA (COPENHAGEN, DENMARK : 1989) 1996; 50:848-9. [PMID: 8817870 DOI: 10.3891/acta.chem.scand.50-0848] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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