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Henriques J, Amaro AM, Piedade AP. Biomimicking Atherosclerotic Vessels: A Relevant and (Yet) Sub-Explored Topic. Biomimetics (Basel) 2024; 9:135. [PMID: 38534820 DOI: 10.3390/biomimetics9030135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 02/20/2024] [Accepted: 02/21/2024] [Indexed: 03/28/2024] Open
Abstract
Atherosclerosis represents the etiologic source of several cardiovascular events, including myocardial infarction, cerebrovascular accidents, and peripheral artery disease, which remain the leading cause of mortality in the world. Numerous strategies are being delineated to revert the non-optimal projections of the World Health Organization, by both designing new diagnostic and therapeutic approaches or improving the interventional procedures performed by physicians. Deeply understanding the pathological process of atherosclerosis is, therefore, mandatory to accomplish improved results in these trials. Due to their availability, reproducibility, low expensiveness, and rapid production, biomimicking physical models are preferred over animal experimentation because they can overcome some limitations, mainly related to replicability and ethical issues. Their capability to represent any atherosclerotic stage and/or plaque type makes them valuable tools to investigate hemodynamical, pharmacodynamical, and biomechanical behaviors, as well as to optimize imaging systems and, thus, obtain meaningful prospects to improve the efficacy and effectiveness of treatment on a patient-specific basis. However, the broadness of possible applications in which these biomodels can be used is associated with a wide range of tissue-mimicking materials that are selected depending on the final purpose of the model and, consequently, prioritizing some materials' properties over others. This review aims to summarize the progress in fabricating biomimicking atherosclerotic models, mainly focusing on using materials according to the intended application.
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Affiliation(s)
- Joana Henriques
- University of Coimbra, CEMMPRE, ARISE, Department of Mechanical Engineering, 3030-788 Coimbra, Portugal
| | - Ana M Amaro
- University of Coimbra, CEMMPRE, ARISE, Department of Mechanical Engineering, 3030-788 Coimbra, Portugal
| | - Ana P Piedade
- University of Coimbra, CEMMPRE, ARISE, Department of Mechanical Engineering, 3030-788 Coimbra, Portugal
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Valvez S, Oliveira-Santos M, Gonçalves L, Amaro AM, Piedade AP. Preprocedural Planning of Left Atrial Appendage Occlusion: A Review of the Use of Additive Manufacturing. 3D Print Addit Manuf 2024; 11:333-346. [PMID: 38389681 PMCID: PMC10880654 DOI: 10.1089/3dp.2022.0373] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/24/2024]
Abstract
Stroke is a significant public health problem, with non-valvular atrial fibrillation (NVAF) being one of its main causes. This cardiovascular arrhythmia predisposes to the production of intracardiac thrombi, mostly formed in the left atrial appendage (LAA). When there are contraindications to treatment with oral anticoagulants, another therapeutic option to reduce the possibility of thrombus formation in the LAA is the implantation of an occlusion device by cardiac catheterization. The effectiveness of LAA occlusion is dependent on accurate preprocedural device sizing and proper device positioning at the LAA ostium, to ensure sufficient device anchoring and avoid peri-device leaks. Additive manufacturing, commonly known as three-dimensional printing (3DP), of LAA models is beginning to emerge in the scientific literature to address these challenges through procedural simulation. This review aims at clarifying the impact of 3DP on preprocedural planning of LAA occlusion, specifically in the training of cardiac surgeons and in the assessment of the perfect adjustment between the LAA and the biomedical implant.
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Affiliation(s)
- Sara Valvez
- Department of Mechanical Engineering, CEMMPRE, ARISE, University of Coimbra, Coimbra, Portugal
| | | | - Lino Gonçalves
- CBR, Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - Ana M. Amaro
- Department of Mechanical Engineering, CEMMPRE, ARISE, University of Coimbra, Coimbra, Portugal
| | - Ana P. Piedade
- Department of Mechanical Engineering, CEMMPRE, ARISE, University of Coimbra, Coimbra, Portugal
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Pereira MAR, Galvão I, Costa JD, Leal RM, Amaro AM. Joining of Polyethylene Using a Non-Conventional Friction Stir Welding Tool. Materials (Basel) 2022; 15:7639. [PMID: 36363231 PMCID: PMC9655251 DOI: 10.3390/ma15217639] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 10/25/2022] [Accepted: 10/26/2022] [Indexed: 06/16/2023]
Abstract
The objective of the current study was to butt-weld 6 mm-thick polyethylene (PE) plates by friction stir welding (FSW) using a non-conventional stationary shoulder tool. The welds were performed with an unheated shoulder and with a shoulder temperature of 85 °C. Additionally, rotational speeds of 870, 1140 and 1500 rpm; welding speeds of 60 and 120 mm/min; and plunge depths of 5.5 and 5.7 mm were used. The influence of these parameters on morphology, hardness, ultimate tensile strength, elongation at break and fracture modes was evaluated. Shoulder heating proved to be crucial for the optimization of PE joints by FSW, as it clearly improved joint efficiency. Furthermore, shoulder heating promoted the reduction in internal and external defects, such as porosity and surface burning. Defect-free weld seams were obtained with higher rotational speeds and a lower welding speed. A maximum joint efficiency of about 97% was achieved with a shoulder temperature of 85 °C, a rotational speed of 1500 rpm, a welding speed of 60 mm/min and a plunge depth of 5.7 mm. A weld with the average joint efficiency of 92% was produced at 120 mm/min, which based on the literature found is the highest welding speed reported that achieved a joint efficiency above 90%.
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Affiliation(s)
- Miguel A. R. Pereira
- Department of Mechanical Engineering, CEMMPRE, University of Coimbra, 3030-788 Coimbra, Portugal
| | - Ivan Galvão
- Department of Mechanical Engineering, CEMMPRE, University of Coimbra, 3030-788 Coimbra, Portugal
- ISEL, Departamento de Engenharia Mecânica, Instituto Politécnico de Lisboa, Rua Conselheiro Emídio Navarro 1, 1959-007 Lisbon, Portugal
| | - José Domingos Costa
- Department of Mechanical Engineering, CEMMPRE, University of Coimbra, 3030-788 Coimbra, Portugal
| | - Rui M. Leal
- Department of Mechanical Engineering, CEMMPRE, University of Coimbra, 3030-788 Coimbra, Portugal
- LIDA-ESAD.CR, Instituto Politécnico de Leiria, Rua Isidoro Inácio Alves de Carvalho, 2500-321 Caldas da Rainha, Portugal
| | - Ana M. Amaro
- Department of Mechanical Engineering, CEMMPRE, University of Coimbra, 3030-788 Coimbra, Portugal
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Pinho AC, Amaro AM, Piedade AP. 3D printing goes greener: Study of the properties of post-consumer recycled polymers for the manufacturing of engineering components. Waste Manag 2020; 118:426-434. [PMID: 32966947 DOI: 10.1016/j.wasman.2020.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2020] [Revised: 09/05/2020] [Accepted: 09/05/2020] [Indexed: 06/11/2023]
Abstract
This study concerns the evaluation of several properties/characteristics of 3D printed poly(lactic acid) (PLA) polymer and acrylonitrile-butadienestyrene (ABS) copolymer, recycled from food packages and car dashboards, respectively. The aim is to evaluate the potential of recycled polymers that are recovered from solid polymer waste (SPW) to be reused for functional components/parts for add-value applications. The study compared the performance of the recycled material with the obtained from the 3D printing of virgin polymer. The characterization was made considering the chemical, thermal and mechanical properties as well as surface roughness and wettability. Although the thermal characterization did not indicate significant variations between recycled and virgin material, the mechanical recycling process induced some chain scission in PLA. Consequently, the semi-crystalline polymer revealed losses of 33% both in tensile stress and flexural strength. On the contrary, recycled ABS did not show changes in the mechanical properties of the printed specimens. Both recycled polymers produced smoother surfaces with a decrease of the mean surface roughness between 55% and 65%. Considering the properties required by manufacturers of food containers and car dashboards, this study indicates that recycled materials can be reused for the same applications.
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Affiliation(s)
- Ana C Pinho
- University of Coimbra, CEMMPRE, Department of Mechanical Engineering, 3030-788 Coimbra, Portugal
| | - Ana M Amaro
- University of Coimbra, CEMMPRE, Department of Mechanical Engineering, 3030-788 Coimbra, Portugal
| | - Ana P Piedade
- University of Coimbra, CEMMPRE, Department of Mechanical Engineering, 3030-788 Coimbra, Portugal.
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Amaro AM, Paulino MF, Neto MA, Roseiro L. Hand-Arm Vibration Assessment and Changes in the Thermal Map of the Skin in Tennis Athletes during the Service. Int J Environ Res Public Health 2019; 16:E5117. [PMID: 31847390 PMCID: PMC6949913 DOI: 10.3390/ijerph16245117] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2019] [Revised: 12/11/2019] [Accepted: 12/12/2019] [Indexed: 11/21/2022]
Abstract
During recent years the number of tennis athletes has increased significantly. When playing tennis, the human body is exposed to many situations which can lead to human injuries, such as the so-called tennis elbow (lateral epicondylitis). In this work a biomechanical analysis of tennis athletes, particularly during the service, was performed, considering three different types of over-grip and the presence of one anti-vibrator device. One part of the study evaluates the exposure to hand-arm vibration of the athlete, based on the European Directive 2002/44/EC concerning the minimum health and safety requirements, regarding the exposure of workers to risks from physical agents. The second part of the study considers an infrared thermography analysis in order to identify signs of risk of injury, particularly tennis elbow, one of the most common injuries in this sport. The results show that the presence of the anti-vibrator influences the vibration values greatly in the case of athletes with more experience and also for athletes with less performance. The presence of the Cork and/or Tourna on the racket grip does not have any significant effect on the hand-arm vibration (HAV), similarly in the case of athletes with the best performance and athletes with less technique. The results indicated that the infrared thermography technique may be used to identify the risk of injuries in tennis players.
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Affiliation(s)
- Ana M. Amaro
- CEMMPRE, Department of Mechanical Engineering, University of Coimbra, 3004-531 Coimbra, Portugal; (M.F.P.); (M.A.N.); (L.R.)
| | - Maria F. Paulino
- CEMMPRE, Department of Mechanical Engineering, University of Coimbra, 3004-531 Coimbra, Portugal; (M.F.P.); (M.A.N.); (L.R.)
| | - Maria A. Neto
- CEMMPRE, Department of Mechanical Engineering, University of Coimbra, 3004-531 Coimbra, Portugal; (M.F.P.); (M.A.N.); (L.R.)
| | - Luis Roseiro
- CEMMPRE, Department of Mechanical Engineering, University of Coimbra, 3004-531 Coimbra, Portugal; (M.F.P.); (M.A.N.); (L.R.)
- Coimbra Polytechnic-ISEC, 3030-199 Coimbra, Portugal
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Amaro AM, Neto MA, Cirne JS, Reis PNB. Mechanical Characterization of Different Aluminium Foams at High Strain Rates. Materials (Basel) 2019; 12:E1428. [PMID: 31052456 PMCID: PMC6539786 DOI: 10.3390/ma12091428] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/23/2019] [Accepted: 04/26/2019] [Indexed: 12/03/2022]
Abstract
Samples having nominal compositions of AlSi12 and Al6082-T4 were prepared using a lost wax casting process, with nominal relative densities of 20%, 40%, and 60%, as well as arrangements of a uniform cell structure (US) or a dual-size cell (DS). For comparison, samples of aluminium foam-filled tubes having the same nominal composition were also prepared with the same technique, with nominal relative densities of 20% and similar arrangements (US and DS). Impact tests at different velocities were performed using a split Hopkinson pressure bar (SHPB). It is possible to conclude that Al6082-T4 foams have better performance, in both configurations, than the AlSi12 ones. Considering a uniform cell structure and a density of 20%, the absorbed energy by the Al6082-T4 foams was around 25% higher than the value observed for the AlSi12 ones. In terms of arrangement, the US structure presents absorbed energy around 57% lower than the DS ones, while the AlSi12 foams with a relative density of 20% were compared. Finally, the absorbed energy growths from 2.8 × 105 to 5.2 × 105 J/m3, when the density increased from 20% to 60%. However, when these foams were involved with a tube, the performances increased substantially.
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Affiliation(s)
- Ana M Amaro
- CEMMPRE, Department of Mechanical Engineering, University of Coimbra, 3030-194 Coimbra, Portugal.
| | - Maria A Neto
- CEMMPRE, Department of Mechanical Engineering, University of Coimbra, 3030-194 Coimbra, Portugal.
| | - José S Cirne
- Department of Mechanical Engineering, University of Coimbra, 3030-194 Coimbra, Portugal.
| | - Paulo N B Reis
- C-MAST, Department of Electromechanical Engineering, University of Beira Interior, Calçada Fonte do Lameiro, 6201-100 Covilhã, Portugal.
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Lopes VM, Neto MA, Amaro AM, Roseiro LM, Paulino M. FE and experimental study on how the cortex material properties of synthetic femurs affect strain levels. Med Eng Phys 2017. [DOI: 10.1016/j.medengphy.2017.06.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Amaro AM, Reis PNB, de Moura M, Santos JB. Influence of the specimen thickness on low velocity impact behavior of composites. Journal of Polymer Engineering 2012. [DOI: 10.1515/polyeng-2011-0101] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
In this work, the influence of specimen thickness on low velocity impact behavior of carbon-epoxy composite laminates is studied. Plates with different thicknesses were tested under low velocity impact using a hemispherical impactor. The internal damage was mainly constituted by delaminations which were evaluated through the inspection of the impacted plates by the ultrasonic C-scan technique. It was observed that delaminations increase with plate thickness. In order to better understand the physical phenomenon explaining this result, a progressive damage model was used to simulate composites behavior under low velocity impact. In this context, a three-dimensional numerical analysis considering interface finite elements, including a cohesive mixed-mode damage model, which allows simulating delaminations onset and growth between layers, was performed. Good agreement was obtained between experimental and numerical analysis, which validated the proposed procedure. In addition, the proposed numerical methodology allowed identification of physical phenomena related to the influence of plate thickness on delamination size.
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Amaro AM, Hallberg KB, Lindström EB, Jerez CA. An immunological assay for detection and enumeration of thermophilic biomining microorganisms. Appl Environ Microbiol 2010; 60:3470-3. [PMID: 16349398 PMCID: PMC201835 DOI: 10.1128/aem.60.9.3470-3473.1994] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A specific, fast, and sensitive nonradioactive immunobinding assay for the detection and enumeration of the moderate thermophile Thiobacillus caldus and the thermophilic archaeon Sulfolobus acidocaldarius was developed. It employs enhanced chemiluminescence or peroxidase-conjugated immunoglobulins in a dot or slot blotting system and is very convenient for monitoring thermophilic bioleaching microorganisms in effluents from industrial bioleaching processes.
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Affiliation(s)
- A M Amaro
- Departamento de Bioquímica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
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Amaro AM, Fuentes MS, Ogalde SR, Venegas JA, Suárez-Isla BA. Identification and characterization of potentially algal-lytic marine bacteria strongly associated with the toxic dinoflagellate Alexandrium catenella. J Eukaryot Microbiol 2005; 52:191-200. [PMID: 15926994 DOI: 10.1111/j.1550-7408.2005.00031.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The toxic dinoflagellate Alexandrium catenella isolated from fjords in Southern Chile produces several analogues of saxitoxin and has been associated with outbreaks of paralytic shellfish poisoning. Three bacterial strains, which remained in close association with this dinoflagellate in culture, were isolated by inoculating the dinoflagellate onto marine agar. The phenotypically different cultivable bacterial colonies were purified. Their genetic identification was done by polymerase chain reaction amplification of the 16S rRNA genes. Partial sequence analysis suggested that the most probable affiliations were to two bacterial phyla: Proteobacteria and the Cytophaga group. The molecular identification was complemented by morphological data and biochemical profiling. The three bacterial species, when grown separately from phytoplankton cells in high-nutrient media, released algal-lytic compounds together with aminopeptidase, lipase, glucosaminidase, and alkaline phosphatase. When the same bacteria, free of organic nutrients, were added back to the algal culture they displayed no detrimental effects on the dinoflagellate cells and recovered their symbiotic characteristics. This observation is consistent with phylogenetic analysis that reveals that these bacteria correspond to species distinct from other bacterial strains previously classified as algicidal bacteria. Thus, bacterial-derived lytic activities are expressed only in the presence of high-nutrient culture media and it is likely that in situ environmental conditions may modulate their expression.
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Affiliation(s)
- Ana M Amaro
- Laboratory of Marine Toxins, Program of Physiology and Biophysics, Institute of Biomedical Sciences, Faculty of Medicine, University of Chile, Santiago 6530499, Chile.
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Jerez CA, Seeger M, Amaro AM. Phosphate starvation affects the synthesis of outer membrane proteins in Thiobacillus ferrooxidans. FEMS Microbiol Lett 1992; 77:29-33. [PMID: 1459418 DOI: 10.1016/0378-1097(92)90127-a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
The outer membrane protein (omp40) component from the chemolithoautotrophic acidophilic Thiobacillus ferrooxidans is apparently regulated by the external pH and the concentration of phosphorus. Its amino-terminal sequence showed little identity with the Escherichia coli OmpC, OmpF or PhoE porins, but was 38.5% identical to the outer membrane channel-forming protein NosA from Pseudomonas stutzeri, whose expression is also regulated environmentally. In addition, the partial amino acid sequence of T. ferrooxidans omp40 showed between 34 and 38% identity with the amino-terminal end of the small outer membrane proteins Rck and PagC from Salmonella typhimurium and OmpX from Enterobacter cloacae.
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Affiliation(s)
- C A Jerez
- Departamento de Bioquímica, Facultad de Medicina, Universidad de Chile, Santiago
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Acuña J, Rojas J, Amaro AM, Toledo H, Jerez CA. Chemotaxis of Leptospirillum ferrooxidans and other acidophilic chemolithotrophs: comparison with the Escherichia coli chemosensory system. FEMS Microbiol Lett 1992; 75:37-42. [PMID: 1526464 DOI: 10.1016/0378-1097(92)90453-u] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Ni2+, Fe2+ and Cu2+ were attractants and aspartate was an apparent repellent for Leptospirillum ferrooxidans, a behaviour opposite to that for Escherichia coli. Membranes from L. ferrooxidans contained proteins with a molecular mass in the range of 80 kDa which were methylated in vitro. Methylation was stimulated in the presence of a membrane-free extract from E. coli, showing the response pattern expected for L. ferrooxidans, increased methylation by Ni2+, and demethylation by aspartate. This suggests the existence of sensory transducers having a common methylation domain with the E. coli methyl-accepting chemotaxis proteins. Total chromosomal DNA digests from L. ferrooxidans, Thiobacillus ferrooxidans and T. thiooxidans hybridized with probes containing different domains of the tar gene from E. coli, implying the presence of tar type genes in the acidophilic bacteria studied.
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Affiliation(s)
- J Acuña
- Departamento de Bioquímica, Facultad de Medicina, Universidad de Chile, Santiago
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Toledo H, Amaro AM, Sanhueza S, Jerez CA. Methylation of proteins from the translational apparatus: an overview. Arch Biol Med Exp 1988; 21:219-29. [PMID: 3154861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Several of the translational apparatus proteins are methylated in all kinds of organisms. Although most of the modified proteins play key roles during protein biosynthesis, the biological function of these chemical modifications still remains elusive. Our recent data indicate a highly conserved pattern of ribosomal protein methylation in eubacteria, with methylated proteins being both structurally and functionally homologous in several microorganisms. Chloroplast ribosomes also appear to have a rather eubacterial pattern of ribosomal protein methylation. On the other hand, there is an apparently ubiquitous methylation of some of the translational factors in several organisms. These findings suggest an important, albeit unknown role for the post-synthetic methylation of the translational machinery. The analysis of the sequences of known methylation target sites and the search of similar sites in other proteins of known sequence, allows to predict those ribosomal proteins or translational factors that may be subjected to post-translational modifications with one or more methyl groups. Although a definitive answer with respect to the biological role of these N-methylations is still missing, a direct correlation between the methylation of some proteins and their biological activity is just beginning to emerge.
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Affiliation(s)
- H Toledo
- Departamento de Bioquímica, Facultad de Medicina, Universidad de Chile, Santiago
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Abstract
Methylation of the 50S ribosomal proteins from Bacillus stearothermophilus, Bacillus subtilis, Alteromonas espejiana, and Halobacterium cutirubrum was measured after the cells were grown in the presence of [1-14C]methionine or [methyl-3H]methionine or both. Two-dimensional polyacrylamide gel electrophoretic analysis revealed, in general, similar relative electrophoretic mobilities of the methylated proteins from each eubacterium studied. Proteins known to be structurally and functionally homologous in several microorganisms were all methylated. Thus, the following group of proteins, which appear to be involved in peptidyltransferase or in polyphenylalanine-synthesizing activity in B. stearothermophilus (P.E. Auron and S. R. Fahnestock, J. Biol. Chem. 256:10105-10110, 1981), were methylated (possible Escherichia coli methylated homologs are indicated in parentheses): BTL5(EL5), BTL6(EL3), BTL8(EL10), BTL11(EL11), BTL13(EL7L12) and BTL20b(EL16). In addition, the pentameric ribosomal complex BTL13 X BTL8, analogous to the complex EL7L12 X EL10 of E. coli, contained methylated proteins. Analysis of the methylated amino acids in the most heavily methylated proteins, BSL11 from B. subtilis and BTL11 from B. stearothermophilus, showed the presence of epsilon-N-trimethyllysine as the major methylated amino acid in both proteins, in agreement with known data for E. coli. In addition, BSL11 appeared to contain trimethylalanine, a characteristic, modified amino acid previously described only in EL11 from E. coli. These results and those previously obtained from other bacteria indicate a high degree of conservation for ribosomal protein methylation and suggest an important, albeit unknown, role for the modification of these components in eubacterial ribosomes.
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Abstract
We measured the methylation of ribosomal proteins from the 30S and 50S subunits of Bacillus subtilis after growing the cells in the presence of [1-14C]methionine and [methyl-3H]methionine. Two-dimensional polyacrylamide gel electrophoretic analysis revealed a preferential methylation of the 50S ribosomal proteins. Proteins L11 and L16, and possibly L9, L10, L18, and L20, were methylated. On the other hand, only two possibly methylated proteins were found on the 30S subunit. A comparison of these results with those for Escherichia coli suggests a common methylation pattern for the bacterial ribosomal proteins.
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Jerez CA, Mardones E, Amaro AM. Studies on the ribosomal proteins of Bacillus subtilis during sporulation. Arch Biol Med Exp 1979; 12:379-87. [PMID: 121909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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