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Wang X, Zhao L, Liu C, Qi J, Zhao P, Liu Z, Li C, Hu Y, Yin X, Liu X, Liao Z, Zhang L, Xia X. New Tetramic Acids Comprising of Decalin and Pyridones From Chaetomium olivaceum SD-80A With Antimicrobial Activity. Front Microbiol 2020; 10:2958. [PMID: 32010075 PMCID: PMC6974552 DOI: 10.3389/fmicb.2019.02958] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Accepted: 12/09/2019] [Indexed: 12/22/2022] Open
Abstract
Cycloaddition reactions such as intramolecular Diels–Alder (IMDA) are extremely important in constructing multicyclic scaffolds with diverse bioactivities. Using MycB as a biomarker, three new polyketides – Chaetolivacines A (1), B (3), and C (4) – with one known compound Myceliothermophin E (2) comprising of decalin and 4-hydroxy-2-pyridones were obtained from the culture of Chaetomium olivaceum SD-80A under the guidance of gene mining. The structures of these compounds were established using detailed 1D, 2D NMR, and high-resolution electron spray ionization mass spectroscopy (HRESIMS) analysis. The relative and absolute configurations of the compounds 1, 3, and 4 were elucidated by NOESY and ECD. The biosynthesis pathways of these compounds were proposed, which involves in three key genes ChaA [polyketide synthase-non-ribosomal peptide synthetases (PKS-NRPS)], ChaB, and ChaC. Compounds 1–4 were tested for their antimicrobial activities, and compounds 2 and 3 showed moderate bioactivity against Staphylococcus aureus (SA) and methicillin-resistant S. aureus (MRSA) with MIC values of 15.8 and 27.1 μM. The results showed that configuration of C-21 in 3 and 4 is important for anti-SA and anti-MRSA activities. This study reveals the significant potential of the genus Chaetomium in producing new PKS-NRPS, therefore increasing the speed in the mining for new sources of antimicrobial agents.
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Affiliation(s)
- Xinzhu Wang
- Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, China
| | - Liya Zhao
- Shandong Provincial Key Laboratory for Biosensor, Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Chao Liu
- Institute of Agro-Food Science and Technology, Shandong Academy of Agricultural Sciences, Jinan, China
| | - Jun Qi
- Shandong Provincial Key Laboratory for Biosensor, Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Peipei Zhao
- Shandong Provincial Key Laboratory for Biosensor, Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Zhaoming Liu
- Guangdong Institute of Microbiology, Guangdong Academy of Sciences, Guangzhou, China
| | - Chunlei Li
- Shandong Provincial Key Laboratory for Biosensor, Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Yingying Hu
- Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, China
| | - Xin Yin
- Shandong Provincial Key Laboratory for Biosensor, Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Xin Liu
- Shandong Provincial Key Laboratory for Biosensor, Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
| | - Zhixin Liao
- Department of Pharmaceutical Engineering, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, China
| | - Lixin Zhang
- Shandong Provincial Key Laboratory for Biosensor, Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China.,State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China
| | - Xuekui Xia
- Shandong Provincial Key Laboratory for Biosensor, Biology Institute, Qilu University of Technology (Shandong Academy of Sciences), Jinan, China
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Johnson LB, Venugopal AA, Pawlak J, Saravolatz LD. Emergence of Community-Associated Methicillin-ResistantStaphylococcus aureusInfection Among Patients With End-Stage Renal Disease. Infect Control Hosp Epidemiol 2016; 27:1057-62. [PMID: 17006812 DOI: 10.1086/507958] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2006] [Accepted: 06/14/2006] [Indexed: 11/04/2022]
Abstract
Objective.To evaluate the frequency of infections due to community-associated methicillin-resistantStaphylococcus aureus(CA-MRSA) strains among our patients with end-stage renal disease.Design.Prospective observational clinical and laboratory study of patients in 2005. Molecular features of isolates recovered from these patients were compared with those of isolates recovered in 2000 from patients with end-stage renal disease.Setting.A 600-bed urban academic medical center.Patients.Thirty-two patients with end-stage renal disease and MRSA infection at the time of hospitalization from 2005 were evaluated. For comparison, laboratory analysis was performed for 17 MRSA isolates recovered from patients with end-stage renal disease in 2000.Results.The patients from 2005 were more likely than the patients from 2000 to have infection with strains that carried the staphylococcal cassette chromosome (SCC)mectype IV complex (50% vs 11.8%; relative risk, 4.25 [95% confidence interval, 1.17-25.98];P= .012) and the Panton-Valentine leukocidin toxin genes (25% vs 0%;P= .038). Eight patients from 2005 were infected with a strain that is identical to MRSA clone USA300 in terms of molecular type and presence of SCCmectype IV and Panton-Valentine leukocidin genes. Among the patients from 2005, those infected with SCCmectype IV strains (ie, CA-MRSA strains) and those infected with SCCmectype II strains (ie, healthcare-associated MRSA [HA-MRSA] strains) were similar with respect to demographic characteristics, risk factors, and outcomes.Conclusions.We documented an increased proportion of infections with CA-MRSA strains, including clone USA300, among our population of patients undergoing dialysis. Patients infected with CA-MRSA strains and HA-MRSA strains were similar with respect to presenting illness and outcomes.
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Affiliation(s)
- Leonard B Johnson
- Department of Internal Medicine, St. John Hospital and Medical Center, Detroit, MI, USA.
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Peña MI, Van Itallie E, Bennett MR, Shamoo Y. Evolution of a single gene highlights the complexity underlying molecular descriptions of fitness. CHAOS (WOODBURY, N.Y.) 2010; 20:026107. [PMID: 20590336 PMCID: PMC2909312 DOI: 10.1063/1.3453623] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 05/23/2010] [Indexed: 05/29/2023]
Abstract
Evolution by natural selection is the driving force behind the endless variation we see in nature, yet our understanding of how changes at the molecular level give rise to different phenotypes and altered fitness at the population level remains inadequate. The reproductive fitness of an organism is the most basic metric that describes the chance that an organism will succeed or fail in its environment and it depends upon a complex network of inter- and intramolecular interactions. A deeper understanding of the quantitative relationships relating molecular evolution to adaptation, and consequently fitness, can guide our understanding of important issues in biomedicine such as drug resistance and the engineering of new organisms with applications to biotechnology. We have developed the "weak link" approach to determine how changes in molecular structure and function can relate to fitness and evolutionary outcomes. By replacing adenylate kinase (AK), an essential gene, in a thermophile with a homologous AK from a mesophile we have created a maladapted weak link that produces a temperature-sensitive phenotype. The recombinant strain adapts to nonpermissive temperatures through point mutations to the weak link that increase both stability and activity of the enzyme AK at higher temperatures. Here, we propose a fitness function relating enzyme activity to growth rate and use it to create a dynamic model of a population of bacterial cells. Using metabolic control analysis we show that the growth rate exhibits thresholdlike behavior, saturating at high enzyme activity as other reactions in the energy metabolism pathway become rate limiting. The dynamic model accurately recapitulates observed evolutionary outcomes. These findings suggest that in vitro enzyme kinetic data, in combination with metabolic network analysis, can be used to create fitness functions and dynamic models of evolution within simple metabolic systems.
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Affiliation(s)
- Matthew I Peña
- Department of Biochemistry and Cell Biology, Rice University, 6100 Main St., MS-140, Houston, Texas 77005, USA
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Dhawan B, Gadepalli R, Rao C, Kapil A, Sreenivas V. Decreased susceptibility to vancomycin in meticillin-resistant Staphylococcus aureus: a 5 year study in an Indian tertiary hospital. J Med Microbiol 2009; 59:375-376. [PMID: 19959626 DOI: 10.1099/jmm.0.011940-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Affiliation(s)
- Benu Dhawan
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi 29, India
| | - Ravisekhar Gadepalli
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi 29, India
| | - Chandrabhan Rao
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi 29, India
| | - Arti Kapil
- Department of Microbiology, All India Institute of Medical Sciences, New Delhi 29, India
| | - V Sreenivas
- Department of Biostatistics, All India Institute of Medical Sciences, New Delhi 29, India
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Luque Moreno A, Duran Núñez A, Bergadà Masó A, Frick A, Gallés C. Osteomielitis aguda y neumonía comunitaria por Staphylococcus aureus resistente a meticilina. An Pediatr (Barc) 2008; 68:373-6. [DOI: 10.1157/13117710] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Wang G, Hindler JF, Ward KW, Bruckner DA. Increased vancomycin MICs for Staphylococcus aureus clinical isolates from a university hospital during a 5-year period. J Clin Microbiol 2006; 44:3883-6. [PMID: 16957043 PMCID: PMC1698298 DOI: 10.1128/jcm.01388-06] [Citation(s) in RCA: 282] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Staphylococcus aureus is one of the most commonly isolated organisms in nosocomial infections. While the prevalence of methicillin-resistant S. aureus (MRSA) continues to increase worldwide, there is concern about an increase in vancomycin MICs among S. aureus strains. The prevalence of MRSA and vancomycin MIC trends in S. aureus from patients in a university hospital were analyzed. Clinical Laboratory Standards Institute (CLSI, formerly NCCLS) reference broth microdilution MIC testing was performed on all clinically relevant S. aureus isolates from January 2000 through December 2004. A total of 6,003 S. aureus isolates were analyzed. No vancomycin-resistant S. aureus isolates were detected. One MRSA isolate had a vancomycin MIC of 8 mug/ml and was confirmed as vancomycin-intermediate S. aureus. Among the 6,002 remaining isolates, a shift in vancomycin MICs from </=0.5 to 1.0 mug/ml was observed during the 5-year period. The percentage of S. aureus isolates with a vancomycin MIC of 1 mug/ml in 2004 was significantly higher than the percentage of isolates in 2000 (70.4% versus 19.9%; P < 0.01). This vancomycin MIC shift was more notable in methicillin-susceptible S. aureus. Our 5 years of routine testing of clinical isolates using the CLSI reference broth microdilution MIC method demonstrated a tendency toward decreasing susceptibility to vancomycin in S. aureus.
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Affiliation(s)
- Guiqing Wang
- Clinical Microbiology Laboratory, Medical Center of the University of California at Los Angeles, 10833 LeConte Avenue, Los Angeles, CA 90095-1713, USA.
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