Publications by authors named "Marcelo Campos"

50 Publications

Round and round it goes: a cyclic nucleotide modulates stress responses in plants.

Plant Physiol 2022 03;188(4):1942-1943

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78050-900, Brazil.

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http://dx.doi.org/10.1093/plphys/kiac004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8968291PMC
March 2022

It's a model and it's looking good: A multi-organ metabolic model predicts developmental responses in tomato.

Plant Physiol 2022 03;188(3):1417-1418

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá, Mato Grosso 78068-600, Brazil.

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http://dx.doi.org/10.1093/plphys/kiab597DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8896620PMC
March 2022

Residency training for minimally invasive surgery.

Rev Col Bras Cir 2022 28;49:e20213040. Epub 2022 Feb 28.

- Hospital das Clínicas da Universidade Federal de Minas Gerais, Centro de Treinamento e Educação Cirúrgica - Belo Horizonte - MG - Brasil.

Objective: to develop a training program in minimally invasive surgery, based on simulation and with an emphasis on the acquisition of laparoscopic competences.

Methods: this was a prospective, observational study carried out at a university hospital in Belo Horizonte, Brazil, between April 2020 and January 2021. We recruited residents of surgical specialties for structured, progressive training according to instructional principles to promote learning, such as motivation, activation, demonstration, application, and integration. We filmed the skill tests at the program's beginning, middle, and end, which were then anonymously evaluated by a surgical education expert. Individual performances were scored using the global assessment tools "GOALS" and "specific checklist for suture". At the end, all participants received individual feedback and completed a questionnaire to assess the impact of training on the Kirkpatrick model.

Results: 43 residents completed the program. The evolution of performances was evident and grew between tests. The average achievements were 29% in the initial test, 43% in the intermediate test, and 88% in the final test, with significant differences between all mean scores, with H=97.59, GL=2, p<0.0001. The program evaluation and learning perceptions were excellent, but only 10.7% of residents felt fully capable of performing unsupervised, low-complexity laparoscopic surgery at the end of training.

Conclusions: the training program developed in this study proved to be feasible and promising as a strategy for teaching laparoscopic surgery.
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http://dx.doi.org/10.1590/0100-6991e-20213040DOI Listing
March 2022

Waking up for defense! Melatonin as a regulator of stomatal immunity in plants.

Plant Physiol 2022 01;188(1):14-15

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil.

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http://dx.doi.org/10.1093/plphys/kiab481DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8774749PMC
January 2022

BRing on the fight! Brassinosteroid-related transcription factors modulate resistance to fungi attack in wheat.

Plant Physiol 2021 12;187(4):2350-2351

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil.

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http://dx.doi.org/10.1093/plphys/kiab459DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8644128PMC
December 2021

Into a dilemma of plants: the antagonism between chemical defenses and growth.

Plant Mol Biol 2021 Nov 29. Epub 2021 Nov 29.

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá, MT, Brazil.

Key Message: Chemical defenses are imperative for plant survival, but their production is often associated with growth restrictions. Here we review the most recent theories to explain this complex dilemma of plants. Plants are a nutritional source for a myriad of pests and pathogens that depend on green tissues to complete their life cycle. Rather than remaining passive victims, plants utilize an arsenal of chemical defenses to fend off biotic attack. While the deployment of such barriers is imperative for survival, the production of these chemical defenses is typically associated with negative impacts on plant growth. Here we discuss the most recent theories which explain this highly dynamic growth versus defense dilemma. Firstly, we discuss the hypothesis that the antagonism between the accumulation of chemical defenses and growth is rooted in the evolutionary history of plants and may be a consequence of terrestrialization. Then, we revise the different paradigms available to explain the growth versus chemical defense antagonism, including recent findings that update these into more comprehensive and plausible theories. Finally, we highlight state-of-the-art strategies that are now allowing the activation of growth and the concomitant production of chemical barriers in plants. Growth versus chemical defense antagonism imposes large ecological and economic costs, including increased crop susceptibility to pests and pathogens. In a world where these plant enemies are the main problem to increase food production, we believe that this review will summarize valuable information for future studies aiming to breed highly defensive plants without the typical accompanying penalties to growth.
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http://dx.doi.org/10.1007/s11103-021-01213-0DOI Listing
November 2021

Breaking the code of auxin metabolism: an additional role for DIOXYGENASE FOR AUXIN OXIDATION 1.

Plant Physiol 2021 09;187(1):7-8

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá/MT, 78060-900, Brazil.

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http://dx.doi.org/10.1093/plphys/kiab287DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8418390PMC
September 2021

Moving around in a phototropic response: the phosphorylation of NPH3.

Plant Physiol 2021 10;187(2):678-680

Instituto de Agrobiotecnología del Litoral (UNL-Conicet), Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Santa Fe, Argentina.

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http://dx.doi.org/10.1093/plphys/kiab358DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8491030PMC
October 2021

The curvature of gold nanoparticles influences the exposure of amyloid-β and modulates its aggregation process.

Mater Sci Eng C Mater Biol Appl 2021 Sep 23;128:112269. Epub 2021 Jun 23.

Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Chile; Advanced Center for Chronic Diseases (ACCDis), Chile. Electronic address:

Gold nanoparticles (GNP) are tunable nanomaterials that can be used to develop rational therapeutic inhibitors against the formation of pathological aggregates of proteins. In the case of the pathological aggregation of the amyloid-β protein (Aβ), the shape of the GNP can slow down or accelerate its aggregation kinetics. However, there is a lack of elementary knowledge about how the curvature of GNP alters the interaction with the Aβ peptide and how this interaction modifies key molecular steps of fibril formation. In this study, we analysed the effect of flat gold nanoprisms (GNPr) and curved gold nanospheres (GNS) on in vitro Aβ42 fibril formation kinetics by using the thioflavin-based kinetic assay and global fitting analysis, with several models of aggregation. Whereas GNPr accelerate the aggregation process and maintain the molecular mechanism of aggregation, GNS slow down this process and modify the molecular mechanism to one of fragmentation/secondary nucleation, with respect to controls. These results can be explained by a differential interaction between the Aβ peptide and GNP observed by Raman spectroscopy. While flat GNPr expose key hydrophobic residues involved in the Aβ peptide aggregation, curved GNS hide these residues from the solvent. Thus, this study provides mechanistic insights to improve the rational design of GNP nanomaterials for biomedical applications in the field of amyloid-related aggregation.
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http://dx.doi.org/10.1016/j.msec.2021.112269DOI Listing
September 2021

Metallic Action! The Dynamics of a Tripartite Iron Uptake Complex in Arabidopsis Roots.

Plant Physiol 2020 11;184(3):1212-1213

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, 78060-900 Cuiabá/MT, Brazil

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http://dx.doi.org/10.1104/pp.20.01271DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7608156PMC
November 2020

Intranasal administration of gold nanoparticles designed to target the central nervous system: Fabrication and comparison between nanospheres and nanoprisms.

Int J Pharm 2020 Nov 6;590:119957. Epub 2020 Oct 6.

Laboratory for Biopharmaceutics, Department of Biomedical Engineering, Ben Gurion University of the Negev, E.D. Bergmann Campus, Be'er Sheva 84105, Israel. Electronic address:

The presence of the blood-brain barrier (BBB) limit gold nanoparticles (GNP) accumulation in central nervous system (CNS) after intravenous (IV) administration. The intranasal (IN) route has been suggested as a good strategy for circumventing the BBB. In this report, we used gold nanoprisms (78 nm) and nanospheres (47 nm), of comparable surface areas (8000 vs 7235 nm) functionalized with a polyethylene glycol (PEG) and D1 peptide (GNPr-D1 and GNS-D1, respectively) to evaluate their delivery to the CNS after IN administration. Cell viability assay showed that GNPr-D1 and GNS-D1 were not cytotoxic at concentrations ranged between 0.05 and 0.5 nM. IN administration of GNPr-D1 and GNS-D1 demonstrated a significant difference between the two types of GNP, in which the latter reached the CNS in higher levels. Pharmacokinetic study showed that the peak brain level of gold was 0.75 h after IN administration of GNS-D1. After IN and IV administrations of GNS-D1, gold concentrations found in brain were 55 times higher via the IN route compared to IV administration. Data revealed that the IN route is more effective for targeting gold to the brain than IV administration. Finally, no significant difference was observed between the IN and IV routes in the distribution of GNS-D1 in the various brain areas.
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http://dx.doi.org/10.1016/j.ijpharm.2020.119957DOI Listing
November 2020

Vertical Continuous Meniscal Suture Technique.

Arthrosc Tech 2020 Sep 10;9(9):e1335-e1340. Epub 2020 Sep 10.

Knee Surgery Center, National Institute of Traumatology and Orthopedics of Brazil, Rio de Janeiro, Brazil.

Meniscal injuries are common in the population, representing the major cause of functional impairment in the knee. Vertical longitudinal injuries of the meniscus can be stable or unstable. When extensive, they are commonly unstable and can lead to clinical signs of significant functional disability. Vertical longitudinal injuries have the best prognosis for repair, especially when occurring in the meniscal periphery, called the red-red zone. A recently developed type of meniscal suture device called Meniscus 4 A-II enables the surgeon to perform a meniscal suture from the inside-out continuously, reducing surgical time. Because it allows the surgeon to use a single and inexpensive device to repair the entire injury, costs are significantly reduced. Here, an approach to carry out continuous meniscal repair with vertical sutures is described. This technique warrants excellent stability to the meniscal repair, increasing the chances of a successful outcome. We believe that the popularization of the repair technique from the inside out using the Meniscus 4-All device will help many surgeons around the world save menisci that otherwise would have a great chance of being excised, since it is a cheap, reproducible, and easy-to-handle device.
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http://dx.doi.org/10.1016/j.eats.2020.05.014DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7528575PMC
September 2020

Adsorption of bovine serum albumin on gold nanoprisms: interaction and effect of NIR irradiation on protein corona.

J Mater Chem B 2020 09;8(37):8644-8657

Advanced Center for Chronic Diseases (ACCDiS), Santos Dumont 964, Independencia, Santiago, Chile and Departamento de Ciencias Químicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. Republica 275, Santiago, Chile.

Because of their photothermal properties, gold nanoparticles (AuNPs) have gained attention regarding their use in drug delivery and therapeutic applications. In this sense, it is interesting to consider their interactions with biologically available proteins, such as serum albumin, as well as the effects of irradiation and photothermal conversion on the protein structure that can lead to a loss of function or generate an immune response. Gold nanoprisms (AuNPrs) have gained interest due to their low toxicity, ease of synthesis, and excellent stability, promoting their use in bioapplications such as surface-enhanced Raman spectroscopy (SERS), drug delivery, and photothermal therapy. The interaction between AuNPrs, with plasmon bands centred in the near-infrared region (NIR), and bovine serum albumin (BSA) has not been explored yet. UV-Vis spectroscopy, dynamic light scattering (DLS) and fluorescence spectroscopy were used to study the interaction between AuNPrs and BSA in addition to estimation of the adsorption rate and kinetic and thermodynamic parameters (K, ΔH°, ΔG°, ΔS°, and Ea) using adsorption isotherms and Langmuir and Freundlich models. The results suggest spontaneous cooperative binding in multilayer adsorption, achieved by the chemisorption of BSA on the AuNPr surface through the S-Au interaction, as confirmed by Raman spectroscopy. On the other hand, the photothermal conversion efficiency (PE) of the coated nanoparticles after NIR irradiation was assessed, resulting in a slight decrease in the PE of BSA coated on AuNPrs in comparison with that of noncapped nanoparticles. The effect of the irradiation on the protein conformation of capped nanoparticles was also assessed; circular dichroism showed BSA unfolding upon interaction with AuNPrs, with a decrease in the α-helix and β-sheet contents, as well as an increase in random coil conformations. Changes in the Raman spectrum suggest a modification of the disposition of the protein residues exposed to the gold surface after NIR irradiation; but at the secondary structure level, no relevant changes were observed. This provides possibilities for the use of NPs-BSA for bioapplications based on the photothermal effect promoted by laser irradiation, since the biological identity of the protein is preserved after NIR irradiation.
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http://dx.doi.org/10.1039/d0tb01246gDOI Listing
September 2020

A Novel Regulator of Stomatal Immunity in Tomato.

Plant Physiol 2020 07;183(3):820-821

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, 78060-900 Cuiabá/Mato Grosso, Brazil

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http://dx.doi.org/10.1104/pp.20.00655DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7333718PMC
July 2020

Development and validation a task-specific checklist for a microsurgical varicocelectomy simulation model.

Int Braz J Urol 2020 Sep-Oct;46(5):796-802

Department of Urology, United Hospital Center, Bridgeport, West Virginia, USA, United States.

Purpose: To develop and validate a new test of specific technical skills required for microsurgical varicocelectomy.

Materials And Methods: An electronic questionnaire was sent to 558 members of the Brazilian Society of Urology for the validation of the task-specific checklist (TSC) for assessment of microsurgical varicocelectomy. Participants who had experience in this procedure were selected as judges. For construct validation, 12 participants including attending urologists and urological residents in training were recruited for voluntary participation. We formed a group of three experts and a group of nine novices, who had to perform the steps of microsurgical varicocelectomy on a simulation model using human placenta. Each participant was filmed and two blinded raters would then evaluate their performance using the TSC of microsurgical varicocelectomy.

Results: 14 judges were recruited. The assessment tool was reformulated, according to the judges suggestions and had the content validity achieved. The final version of the TSC was comprised of the task-specific score, a series of 4 items scored in a binary fashion designed for microscopic sub-inguinal varicocelectomy. The differences between the performance of participants with different levels of experience reflected the construct validity. The reliability between the raters was high. The mean time required to complete the training of microsurgical varicocelectomy in simulation model was significantly shorter for experts compared to novices (201 vs. 496 seconds, p=0.01).

Conclusions: This preliminary study suggests that the task-specific checklist of microsurgical varicocelectomy is reliable and valid in assessing microsurgical skills.
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http://dx.doi.org/10.1590/S1677-5538.IBJU.2019.0571DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7822372PMC
December 2020

Validation of the Objective Structured Assessment of Technical Skill in Brasil.

Rev Assoc Med Bras (1992) 2020 Mar;66(3):328-333

. Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil.

Background: The aim of this study was to perform a cross-cultural adaptation of the Objective Structured Assessment of Technical Skill (OSATS) tool into Brazilian Portuguese and to determine its reproducibility and validity in Brasil.

Methods: A Brazilian Portuguese version of OSATS was created through a process of translation, back-translation, expert panel evaluation, pilot testing, and then its validation. For the construct and the concurrent validities, twelve participants were divided into a group of six experts and six novices, who had to perform tasks on a simulation model using human placentas. Each participant was filmed, and two blinded raters would then evaluate their performance using the traditional subjective method and then the Brazilian Portuguese version of OSATS.

Results: The Brazilian Portuguese version of OSATS had the face, content, construct, and concurrent validities achieved. The average experts' score and standard deviations were 34 and 0.894, respectively, for Judge 1 and 34.33 and 0.816 for Judge 2. In the case of novices, it was 13.33 and 2.388 for Judge 1 and 13.33 and 3.204 for Judge 2. The concordance between the judges was evident, with the Correlation Coefficient (Pearson) of 0.9944 with CI 95% between 0.9797 and 0.9985, with p < 10-10, evidencing the excellent reproducibility of the instrument.

Conclusion: This preliminary study suggests that the Brazilian Portuguese version of OSATS can reliably and validly assess surgical skills in Brasil.
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http://dx.doi.org/10.1590/1806-9282.66.3.328DOI Listing
March 2020

Gearing Up the Clock of Hypocotyl Growth!

Plant Physiol 2020 06;183(2):433-434

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá/Mato Grosso, 78060-900 Brazil.

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http://dx.doi.org/10.1104/pp.20.00540DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7271770PMC
June 2020

A Novel Role for a Phospholipase D in Plant Immunity.

Plant Physiol 2020 05;183(1):33-34

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, 78060-900 Cuiabá/MT, Brazil

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http://dx.doi.org/10.1104/pp.20.00352DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7210625PMC
May 2020

Gold Nanoparticles Mediate Improved Detection of β-amyloid Aggregates by Fluorescence.

Nanomaterials (Basel) 2020 Apr 6;10(4). Epub 2020 Apr 6.

Departamento de Química Farmacológica y Toxicológica, Facultad de Ciencias Químicas y Farmacéuticas, Universidad de Chile, Santiago 8380494, Chile.

The early detection of the amyloid beta peptide aggregates involved in Alzheimer's disease is crucial to test new potential treatments. In this research, we improved the detection of amyloid beta peptide aggregates in vitro and ex vivo by fluorescence combining the use of CRANAD-2 and gold nanorods (GNRs) by the surface enhancement fluorescence effect. We synthetized GNRs and modified their surface with HS-PEG-OMe and HS-PEG-COOH and functionalized them with the D1 peptide, which has the capability to selectively bind to amyloid beta peptide. For an in vitro detection of amyloid beta peptide, we co-incubated amyloid beta peptide aggregates with the probe CRANAD-2 and GNR-PEG-D1 observing an increase in the intensity of the fluorescence signal attributed to surface enhancement fluorescence. Furthermore, the surface enhancement fluorescence effect was observed in brain slices of transgenic mice with Alzheimer´s disease co-incubated with CRANAD-2 and GNR-PEG-D1. An increase in the fluorescence signal was observed allowing the detection of aggregates that cannot be detected with the single use of CRANAD-2. Gold nanoparticles allowed an improvement in the detection of the amyloid aggregated by fluorescence in vitro and ex vivo.
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http://dx.doi.org/10.3390/nano10040690DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7221977PMC
April 2020

In the Search for the est Pear.

Plant Physiol 2020 04;182(4):1808-1809

Integrative Plant Research Laboratory, Departamento de Botânica e Ecologia, Instituto de Biociências, Universidade Federal de Mato Grosso, Cuiabá/MT 78060-900, Brazil

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http://dx.doi.org/10.1104/pp.20.00127DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7140933PMC
April 2020

Mosses: Versatile plants for biotechnological applications.

Biotechnol Adv 2020 Jul - Aug;41:107533. Epub 2020 Mar 6.

Centro de Análises Bioquímicas e Proteômicas, Universidade Católica de Brasília, Brasilia, DF, Brazil; Programa de Pós-Graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF, Brazil; Programa de Pós-Graduação em Biologia Animal, Universidade de Brasília, Campus Darcy Ribeiro, Brasília, DF, Brazil. Electronic address:

Mosses have long been recognized as powerful experimental tools for the elucidation of complex processes in plant biology. Recent increases in the availability of sequenced genomes and mutant collections, the establishment of novel technologies for targeted mutagenesis, and the development of viable protocols for large-scale production in bioreactors are now transforming mosses into one of the most versatile tools for biotechnological applications. In the present review, we highlight the astonishing biotechnological potential of mosses and how these plants are being exploited for industrial, pharmaceutical, and environmental applications. We focus on the biological features that support their use as model organisms for basic and applied research, and how these are being leveraged to explore the biotechnological potential in an increasing number of species. Finally, we also provide an overview of the available moss cultivation protocols from an industrial perspective, offering insights into batch operations that are not yet well established or do not even exist in the literature. Our goal is to bolster the use of mosses as factories for the biosynthesis of molecules of interest and to show how these species can be harnessed for the generation of novel and commercially useful bioproducts.
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http://dx.doi.org/10.1016/j.biotechadv.2020.107533DOI Listing
August 2020

Prior exercise training and experimental myocardial infarction: A systematic review and meta-analysis.

Clinics (Sao Paulo) 2020 20;75:e1293. Epub 2020 Jan 20.

Laboratorio de Fisiologia e Bioquimica Experimental, Centro de Educacao Fisica e Deportos, Universidade Federal do Espirito Santo, Vitoria, ES, BR.

Exercising prior to experimental infarction may have beneficial effects on the heart. The objective of this study was to analyze studies on animals that had exercised prior to myocardial infarction and to examine any benefits through a systematic review and meta-analysis. The databases MEDLINE, Google Scholar, and Cochrane were consulted. We analyzed articles published between January 1978 and November 2018. From a total of 858 articles, 13 manuscripts were selected in this review. When animals exercised before experimental infarction, there was a reduction in mortality, a reduction in infarct size, improvements in cardiac function, and a better molecular balance between genes and proteins that exhibit cardiac protective effects. Analyzing heart weight/body weight, we observed the following results - Mean difference 95% CI - -0.02 [-0.61,0.57]. Meta-analysis of the infarct size (% of the left ventricle) revealed a statistically significant decrease in the size of the infarction in animals that exercised before myocardial infarction, in comparison with the sedentary animals -5.05 [-7.68, -2.40]. Analysis of the ejection fraction, measured by echo (%), revealed that animals that exercised before myocardial infarction exhibited higher and statistically significant measures, compared with sedentary animals 8.77 [3.87,13.66]. We conclude that exercise performed prior to experimental myocardial infarction confers cardiac benefits to animals.
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http://dx.doi.org/10.6061/clinics/2020/e1293DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6963162PMC
August 2020

Antiviral peptides as promising therapeutic drugs.

Cell Mol Life Sci 2019 Sep 17;76(18):3525-3542. Epub 2019 May 17.

Universidade de Brasília, Pós-Graduação em Patologia Molecular, Campus Darcy Ribeiro, Brasília, DF, 70910-900, Brazil.

While scientific advances have led to large-scale production and widespread distribution of vaccines and antiviral drugs, viruses still remain a major cause of human diseases today. The ever-increasing reports of viral resistance and the emergence and re-emergence of viral epidemics pressure the health and scientific community to constantly find novel molecules with antiviral potential. This search involves numerous different approaches, and the use of antimicrobial peptides has presented itself as an interesting alternative. Even though the number of antimicrobial peptides with antiviral activity is still low, they already show immense potential to become pharmaceutically available antiviral drugs. Such peptides can originate from natural sources, such as those isolated from mammals and from animal venoms, or from artificial sources, when bioinformatics tools are used. This review aims to shed some light on antimicrobial peptides with antiviral activities against human viruses and update the data about the already well-known peptides that are still undergoing studies, emphasizing the most promising ones that may become medicines for clinical use.
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http://dx.doi.org/10.1007/s00018-019-03138-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7079787PMC
September 2019

A structural perspective of plant antimicrobial peptides.

Biochem J 2018 11 9;475(21):3359-3375. Epub 2018 Nov 9.

Centro de Análises Bioquímicas e Proteômicas, Pós-graduação em Ciências Genômicas e Biotecnologia, Universidade Católica de Brasília, Brasília, DF 70790-160, Brazil

Among the numerous strategies plants have developed to fend off enemy attack, antimicrobial peptides (AMPs) stand out as one of the most prominent defensive barriers that grant direct and durable resistance against a wide range of pests and pathogens. These small proteins are characterized by a compact structure and an overall positive charge. AMPs have an ancient origin and widespread occurrence in the plant kingdom but show an unusually high degree of variation in their amino acid sequences. Interestingly, there is a strikingly conserved topology among the plant AMP families, suggesting that the defensive properties of these peptides are not determined by their primary sequences but rather by their tridimensional structure. To explore and expand this idea, we here discuss the role of AMPs for plant defense from a structural perspective. We show how specific structural properties, such as length, charge, hydrophobicity, polar angle and conformation, are essential for plant AMPs to act as a chemical shield that hinders enemy attack. Knowledge on the topology of these peptides is facilitating the isolation, classification and even structural redesign of AMPs, thus allowing scientists to develop new peptides with multiple agronomical and pharmacological potential.
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http://dx.doi.org/10.1042/BCJ20180213DOI Listing
November 2018

The role of antimicrobial peptides in plant immunity.

J Exp Bot 2018 10;69(21):4997-5011

Centro de Análises Bioquímicas e Proteômicas, Universidade Católica de Brasilia, Brasilia/DF, Brazil.

Selective pressure imposed by millions of years of relentless biological attack has led to the development of an extraordinary array of defense strategies in plants. Among these, antimicrobial peptides (AMPs) stand out as one of the most prominent components of the plant immune system. These small and usually basic peptides are deployed as a generalist defense strategy that grants direct and durable resistance against biotic stress. Even though their name implies a function against microbes, the range of plant-associated organisms affected by these peptides is much broader. In this review, we highlight the advances in our understanding on the role of AMPs in plant immunity. We demonstrate that the capacity of plant AMPs to act against a large spectrum of enemies relies on their diverse mechanism of action and remarkable structural stability. The efficacy of AMPs as a defense strategy is evidenced by their widespread occurrence in the plant kingdom, an astonishing heterogeneity in host peptide composition, and the extent to which plant enemies have evolved effective counter-measures to evade AMP action. Plant AMPs are becoming an important topic of research due to their significance in allowing plants to thrive and for their enormous potential in agronomical and pharmaceutical fields.
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http://dx.doi.org/10.1093/jxb/ery294DOI Listing
October 2018

Exploring the influence of Diels-Alder linker length on photothermal molecule release from gold nanorods.

Colloids Surf B Biointerfaces 2018 Jun 19;166:323-329. Epub 2018 Mar 19.

Departamento de Ciencias Quimicas, Facultad de Ciencias Exactas, Universidad Andres Bello, Av. Republica 275, Santiago, Chile. Electronic address:

We studied the photothermal release of carboxyfluorescein (CF) linked to the gold surface of gold nanorods (GNRs) by two Diels-Alder adducts of different lengths (n = 4 and n = 9). The functionalized GNRs were irradiated with infrared light to produce photothermal release of CF by a retro-Diels-Alder reaction. The adducts were chemisorbed on the GNRs and the functionalized nanoparticles were characterized by UV-vis, DLS, zeta potential and Raman and surface-enhanced Raman spectroscopy (SERS). On the basis of the degree of nanoparticle functionalization and the SERS results, we inferred the orientation of CF on the surface of the gold nanoparticle. Moreover, we determined the photothermal release profiles of CF from the gold surface by laser irradiation. The release was faster for the longer linker (n = 9). SERS revealed that, for the shorter linker (n = 4), molecules are oriented perpendicularly with respect to the gold surface, thereby maintaining the CF far from the surface. In contrast, the longer linker was observed to be tilted, thus maintaining CF close to the gold surface and therefore potentially favoring the photothermal transfer of energy. These results are relevant for the future development of the spatial and temporal controlled release of drugs by means of gold nanoparticles.
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http://dx.doi.org/10.1016/j.colsurfb.2018.03.021DOI Listing
June 2018

Regulation of growth-defense balance by the JASMONATE ZIM-DOMAIN (JAZ)-MYC transcriptional module.

New Phytol 2017 Sep 26;215(4):1533-1547. Epub 2017 Jun 26.

Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.

The plant hormone jasmonate (JA) promotes the degradation of JASMONATE ZIM-DOMAIN (JAZ) proteins to relieve repression on diverse transcription factors (TFs) that execute JA responses. However, little is known about how combinatorial complexity among JAZ-TF interactions maintains control over myriad aspects of growth, development, reproduction, and immunity. We used loss-of-function mutations to define epistatic interactions within the core JA signaling pathway and to investigate the contribution of MYC TFs to JA responses in Arabidopsis thaliana. Constitutive JA signaling in a jaz quintuple mutant (jazQ) was largely eliminated by mutations that block JA synthesis or perception. Comparison of jazQ and a jazQ myc2 myc3 myc4 octuple mutant validated known functions of MYC2/3/4 in root growth, chlorophyll degradation, and susceptibility to the pathogen Pseudomonas syringae. We found that MYC TFs also control both the enhanced resistance of jazQ leaves to insect herbivory and restricted leaf growth of jazQ. Epistatic transcriptional profiles mirrored these phenotypes and further showed that triterpenoid biosynthetic and glucosinolate catabolic genes are up-regulated in jazQ independently of MYC TFs. Our study highlights the utility of genetic epistasis to unravel the complexities of JAZ-TF interactions and demonstrates that MYC TFs exert master control over a JAZ-repressible transcriptional hierarchy that governs growth-defense balance.
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http://dx.doi.org/10.1111/nph.14638DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5542871PMC
September 2017

Physiological highlights of manganese toxicity symptoms in soybean plants: Mn toxicity responses.

Plant Physiol Biochem 2017 Apr 25;113:6-19. Epub 2017 Jan 25.

UNESP - São Paulo State University, Postal Code 15385-000, Ilha Solteira, SP, Brazil; UNESP - São Paulo State University, Postal Code 17602-496, Tupã, SP, Brazil. Electronic address:

Manganese (Mn) is an essential element for plants; however, high concentrations in certain soil conditions can cause toxicity symptoms in the plant tissue. Here, we describe Mn toxicity symptoms and Mn toxicity responses in soybean plants. Soybean plants exposed to excess Mn showed reductions in the CO assimilation rate and stomatal conductance, which in turn resulted in decreased shoot biomass. Furthermore, peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) activity were higher in plants grown with the highest Mn concentration. The Mn doses increased the activity of antioxidant enzymes such as CAT, POD, and SOD. The toxicity symptoms presented by the leaves included hypertrophying of the adaxial epidermis and the formation of necrotic areas with purple-colored veins. Dramatic movement of calcium from the healthy region to the purple-colored necrotic region was observed, as was the exit of potassium from the necrotic area to the healthy region of the tissue. The high activities of POD and SOD in the presence of high Mn compartmented in the roots was the main physiological responses at high Mn uptake by soybean plants.
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http://dx.doi.org/10.1016/j.plaphy.2017.01.022DOI Listing
April 2017

Rewiring of jasmonate and phytochrome B signalling uncouples plant growth-defense tradeoffs.

Nat Commun 2016 08 30;7:12570. Epub 2016 Aug 30.

Department of Energy-Plant Research Laboratory, East Lansing, Michigan 48824, USA.

Plants resist infection and herbivory with innate immune responses that are often associated with reduced growth. Despite the importance of growth-defense tradeoffs in shaping plant productivity in natural and agricultural ecosystems, the molecular mechanisms that link growth and immunity are poorly understood. Here, we demonstrate that growth-defense tradeoffs mediated by the hormone jasmonate are uncoupled in an Arabidopsis mutant (jazQ phyB) lacking a quintet of Jasmonate ZIM-domain transcriptional repressors and the photoreceptor phyB. Analysis of epistatic interactions between jazQ and phyB reveal that growth inhibition associated with enhanced anti-insect resistance is likely not caused by diversion of photoassimilates from growth to defense but rather by a conserved transcriptional network that is hardwired to attenuate growth upon activation of jasmonate signalling. The ability to unlock growth-defense tradeoffs through relief of transcription repression provides an approach to assemble functional plant traits in new and potentially useful ways.
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http://dx.doi.org/10.1038/ncomms12570DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5155487PMC
August 2016

Molecular cloning of the tomato Hairless gene implicates actin dynamics in trichome-mediated defense and mechanical properties of stem tissue.

J Exp Bot 2016 10 31;67(18):5313-5324. Epub 2016 Jul 31.

Department of Energy-Plant Research Laboratory, Michigan State University, East Lansing, MI 48824, USA Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824, USA

Trichomes are epidermal structures that provide a first line of defense against arthropod herbivores. The recessive hairless (hl) mutation in tomato (Solanum lycopersicum L.) causes severe distortion of trichomes on all aerial tissues, impairs the accumulation of sesquiterpene and polyphenolic compounds in glandular trichomes, and compromises resistance to the specialist herbivore Manduca sexta Here, we demonstrate that the tomato Hl gene encodes a subunit (SRA1) of the highly conserved WAVE regulatory complex that controls nucleation of actin filaments in a wide range of eukaryotic cells. The tomato SRA1 gene spans a 42-kb region containing both Solyc11g013280 and Solyc11g013290 The hl mutation corresponds to a complex 3-kb deletion that removes the last exon of the gene. Expression of a wild-type SRA1 cDNA in the hl mutant background restored normal trichome development, accumulation of glandular trichome-derived metabolites, and resistance to insect herbivory. These findings establish a role for SRA1 in the development of tomato trichomes and also implicate the actin-cytoskeleton network in cytosolic control of specialized metabolism for plant defense. We also show that the brittleness of hl mutant stems is associated with altered mechanical and cell morphological properties of stem tissue, and demonstrate that this defect is directly linked to the mutation in SRA1.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5049383PMC
http://dx.doi.org/10.1093/jxb/erw292DOI Listing
October 2016
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