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1.
Funct Integr Genomics ; 24(6): 190, 2024 Oct 16.
Artículo en Inglés | MEDLINE | ID: mdl-39412676

RESUMEN

Plant Snakin/GASA and defensin peptides are cysteine-rich molecules with a wide range of biological functions. They are included within the large family of plant antimicrobial peptides (AMPs), characterized by their structural stability, broad spectrum of activity, and diverse mechanisms of action. The Dilatata group of Paspalum includes five allotetraploids that share an equivalent genomic formula IIJJ. From RNA-seq data of seedling tissues, we performed an in silico characterization of the defensin and Snakin/GASA genes in these species and diploids with a II and JJ genome formula and studied the evolutionary consequences of polyploidy on the expression of the two AMPs families. A total of 107 defensins (distributed in eight groups) and 145 Snakin/GASA (grouped in three subfamilies) genes were identified. Deletions, duplications and/or gene silencing seem to have mediated the evolution of these genes in the allotetraploid species. In defensin genes, the IIJJ allopolyploids retained the I subgenome defensin copies in some of the identified groups supporting the closeness of their nuclear genome with the I subgenome species. In both AMPs families, orthologous genes in tetraploids exhibit higher similarity to each other than with diploids. This data supports the theory of a single origin for the allotetraploids. Several copies of both defensin and Snakin/GASA genes were detected in the five polyploids which could have arisen due to duplication events occurring independently during the diploidization processes in the allotetraploid taxa.


Asunto(s)
Defensinas , Diploidia , Proteínas de Plantas , Tetraploidía , Defensinas/genética , Defensinas/metabolismo , Proteínas de Plantas/genética , Proteínas de Plantas/metabolismo , Poaceae/genética , Poaceae/metabolismo , Transcriptoma , Regulación de la Expresión Génica de las Plantas , Poliploidía , Filogenia , Perfilación de la Expresión Génica , Evolución Molecular
2.
Front Chem ; 12: 1382954, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38873409

RESUMEN

N-capping (N-cap) and C-capping (C-cap) in biologically active peptides, including specific amino acids or unconventional group motifs, have been shown to modulate activity against pharmacological targets by interfering with the peptide's secondary structure, thus generating unusual scaffolds. The insertion of capping motifs in linear peptides has been shown to prevent peptide degradation by reducing its susceptibility to proteolytic cleavage, and the replacement of some functional groups by unusual groups in N- or C-capping regions in linear peptides has led to optimized peptide variants with improved secondary structure and enhanced activity. Furthermore, some essential amino acid residues that, when placed in antimicrobial peptide (AMP) capping regions, are capable of complexing metals such as Cu2+, Ni2+, and Zn2+, give rise to the family known as metallo-AMPs, which are capable of boosting antimicrobial efficacy, as well as other activities. Therefore, this review presents and discusses the different strategies for creating N- and C-cap motifs in AMPs, aiming at fine-tuning this class of antimicrobials.

3.
Pharmaceutics ; 16(3)2024 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-38543272

RESUMEN

Currently, one of the primary challenges in salmon farming is caligidosis, caused by the copepod ectoparasites Caligus spp. The infection process is determined by the copepod's ability to adhere to the fish skin through the insertion of its chitin-composed filament. In this study, we examined several antimicrobial peptides previously identified in salmonid mucosal secretions, with a primary focus on their potential to bind to chitin as an initial step. The binding capacity to chitin was tested, with hepcidin and piscidin showing positive results. Further assessments involving cytotoxicity in salmonid cells RTgill-W1, SHK-1, RTS-11, and RT-gut indicated that the peptides did not adversely affect cell viability. However, hemolysis assays unveiled the hemolytic capacity of piscidin at lower concentrations, leading to the selection of hepcidin for antiparasitic assays. The results demonstrated that the nauplius II stage of C. rogercresseyi exhibited higher susceptibility to hepcidin treatments, achieving a 50% reduction in parasitic involvement at 50 µM. Utilizing fluorescence and scanning electron microscopy, we observed the localization of hepcidin on the surface of the parasite, inducing significant spherical protuberances along the exoskeleton of C. rogercresseyi. These findings suggest that cysteine-rich AMPs derived from fish mucosa possess the capability to alter the development of the chitin exoskeleton in copepod ectoparasites, making them therapeutic targets to combat recurrent parasitic diseases in salmon farming.

4.
Microb Ecol ; 87(1): 8, 2023 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-38036921

RESUMEN

Changes in the structure and function of the microbiota are associated with various human diseases. These microbial changes can be mediated by antimicrobial peptides (AMPs), small peptides produced by the host and their microbiota, which play a crucial role in host-bacteria co-evolution. Thus, by studying AMPs produced by the microbiota (microbial AMPs), we can better understand the interactions between host and bacteria in microbiome homeostasis. Additionally, microbial AMPs are a new source of compounds against pathogenic and multi-resistant bacteria. Further, the growing accessibility to metagenomic and metatranscriptomic datasets presents an opportunity to discover new microbial AMPs. This review examines the structural properties of microbiota-derived AMPs, their molecular action mechanisms, genomic organization, and strategies for their identification in any microbiome data as well as experimental testing. Overall, we provided a comprehensive overview of this important topic from the microbial perspective.


Asunto(s)
Péptidos Catiónicos Antimicrobianos , Microbiota , Humanos , Péptidos Catiónicos Antimicrobianos/genética , Péptidos Catiónicos Antimicrobianos/farmacología , Péptidos Antimicrobianos , Bacterias/genética , Microbiota/genética , Antibacterianos
5.
Protein Pept Lett ; 30(8): 690-698, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37488753

RESUMEN

BACKGROUND: Antimicrobial resistance is an emerging global health challenge that has led researchers to study alternatives to conventional antibiotics. A promising alternative is antimicrobial peptides (AMPs), produced as the first line of defense by almost all living organisms. To improve its biological activity, the conjugation of AMPs is a promising approach. OBJECTIVE: In this study, we evaluated the N-terminal conjugation of p-Bt (a peptide derived from Bothrops Jararacuçu`s venom) with ferrocene (Fc) and gallic acid (GA). Acetylated and linear versions of p-Bt were also synthesized to evaluate the importance of N-terminal charge and dimeric structure. METHODS: The compounds were obtained using solid-phase peptide synthesis. Circular dichroism, vesicle permeabilization, antimicrobial activity, and cytotoxicity studies were conducted. RESULTS: No increase in antibacterial activity against Escherichia coli was observed by adding either Fc or GA to p-Bt. However, Fc-p-Bt and GA-p-Bt exhibited improved activity against Staphylococcus aureus. No cytotoxicity upon fibroblast was observed for GA-p-Bt. On the other hand, conjugation with Fc increased cytotoxicity. This toxicity may be related to the membrane permeabilization capacity of this bioconjugate, which showed the highest carboxyfluorescein leakage in vesicle permeabilization experiments. CONCLUSION: Considering these observations, our findings highlight the importance of adding bioactive organic compounds in the N-terminal position as a tool to modulate the activity of AMPs.


Asunto(s)
Péptidos Catiónicos Antimicrobianos , Ácido Gálico , Antibacterianos/farmacología , Antibacterianos/química , Péptidos Catiónicos Antimicrobianos/farmacología , Péptidos Catiónicos Antimicrobianos/química , Escherichia coli , Ácido Gálico/farmacología , Metalocenos/farmacología , Pruebas de Sensibilidad Microbiana , Péptidos/química , Péptidos/farmacología , Lisina/química , Lisina/farmacología
6.
Acta Trop ; 236: 106675, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36057367

RESUMEN

Protozoa is a group of microorganisms that cause neglected tropical diseases, such as malaria, Chagas disease, and Leishmaniasis. Due to the growing demand for new therapeutic agents, antimicrobial peptides (AMPs) have gained attention for antiprotozoal action. A systematic literature review described the current scenario of plant and animal AMPs with action antiprotozoal. The terms "antimicrobial peptides", "plant", and "animal" combined with the names of the etiological agents were used in the search. Boolean and Operator were used to connect the terms. The search found 4,825 articles. However, 79 articles were excluded because they were duplicates, and 4,627 were excluded based on title and abstract. Therefore, 119 were evaluated and included here. Of these, the use of antimicrobial peptides of animal origin was predominant. Still, the works with plant peptides focused on the genus Leishmania. Only antimicrobial peptides of animal origin were described for the other genera of protozoa (Toxoplasma spp, Trypanosoma spp, Plasmodium spp). Antimicrobial peptides are an excellent option as a pharmacological tool to fight these infections due to their aggregation and extravasation of cellular content through the formation of pores in the cell membrane of these microorganisms.


Asunto(s)
Antiprotozoarios , Leishmania , Leishmaniasis , Péptidos Antimicrobianos , Antiprotozoarios/uso terapéutico , Humanos , Leishmaniasis/tratamiento farmacológico , Enfermedades Desatendidas/tratamiento farmacológico , Péptidos
7.
Biochimie ; 200: 107-118, 2022 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-35623496

RESUMEN

Antimicrobial resistance has been increasing globally, posing a global public health risk. It has prompted the scientific community to look for alternatives to traditional drugs. Antimicrobial Peptides (AMPs) have stood out in this context because they have the potential to control infectious diseases while causing no or little harm to mammalian cells. In the present study, three peptides, JcTI-PepI, JcTI-PepII, and JcTI-PepIII, were designed and tested for antimicrobial activity based on the primary sequence of JcTI-I, a 2S albumin with trypsin inhibitory activity from Jatropha curcas. JcTI-PepI strongly inhibited C. krusei growth, and it caused severe disruptions in cellular processes and cell morphology. C. krusei cells treated with JcTI-PepI showed indicative of membrane permeabilization and overproduction of Reactive Oxygen Species. Moreover, the yeast's ability to acidify the medium was severely compromised. JcTI-PepI was also effective against pre-formed biofilm and did not harm human erythrocytes and Vero cells. Overall, these characteristics indicate that JcTI-PepI is both safe and effective against C. krusei, an intrinsically resistant strain that causes serious health problems and is frequently overlooked. It implies that this peptide has a high potential for use as a new antimicrobial agent in the future.


Asunto(s)
Antiinfecciosos , Jatropha , Animales , Antiinfecciosos/farmacología , Chlorocebus aethiops , Humanos , Mamíferos , Pruebas de Sensibilidad Microbiana , Péptidos/farmacología , Inhibidores de Tripsina , Células Vero
8.
Front Mol Biosci ; 9: 795255, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35155575

RESUMEN

Approximately four million people contract fungal infections every year in Brazil, primarily caused by Aspergillus spp. The ability of these fungi to form biofilms in tissues and medical devices complicates treatment and contributes to high rates of morbidity and mortality in immunocompromised patients. Psd2 is a pea defensin of 5.4 kDa that possesses good antifungal activity against planktonic cells of representative pathogenic fungi. Its function depends on interactions with membrane and cell wall lipid components such as glucosylceramide and ergosterol. In the present study, we characterized Aspergillus nidulans biofilm formation and determined the effect of Psd2 on A. nidulans biofilms. After 4 hours, A. nidulans conidia adhered to polystyrene surfaces and formed a robust extracellular matrix-producing biofilm at 24 h, increasing thickness until 48 h Psd2 inhibited A. nidulans biofilm formation in a dose-dependent manner. Most notably, at 10 µM Psd2 inhibited 50% of biofilm viability and biomass and 40% of extracellular matrix production. Psd2 significantly decreased the colonized surface area by the biofilm and changed its level of organization, causing a shortening of length and diameter of hyphae and inhibition of conidiophore formation. This activity against A. nidulans biofilm suggests a potential use of Psd2 as a prototype to design new antifungal agents to prevent biofilm formation by A. nidulans and related species.

9.
Funct Integr Genomics ; 22(2): 235-250, 2022 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-35195843

RESUMEN

Plant defensins and lipid transfer proteins (LTPs) constitute a large and evolutionarily diverse family of antimicrobial peptides. Defensins and LTPs are two pathogenesis-related proteins (PR proteins) whose characterization may help to uncover aspects about the sugarcane response to pathogens attack. LTPs have also been investigated for their participation in the response to different types of stress. Despite the important roles of defensins and LTPs in biotic and abiotic stresses, scarce knowledge is found about these proteins in sugarcane. By using bioinformatics approaches, we characterized defensins and LTPs in the sugarcane wild species and modern cultivar genomes. The identification of defensins and LTPs showed that all five defensins groups and eight of the nine LTPs have their respective genes loci, although some was only identified in the cultivar genome. Phylogenetic analysis showed that defensins appear to be more conserved among groups of plants than LTPs. Some defensins and LTPs showed opposite expression during pathogenic and benefic bacterial interactions. Interestingly, the expression of defensins and LTPs in shoots and roots was completely different in plants submitted to benefic bacteria or water depletion. Finally, the modeling and comparison of isoforms of LTPs and defensins in wild species and cultivars revealed a high conservation of tertiary structures, with variation of amino acids in different regions of proteins, which could impact their antimicrobial activity. Our data contributed to the characterization of defensins and LTPs in sugarcane and provided new elements for understanding the involvement of these proteins in sugarcane response to different types of stress.


Asunto(s)
Saccharum , Defensinas/química , Defensinas/genética , Defensinas/metabolismo , Lípidos , Filogenia , Proteínas de Plantas/metabolismo , Saccharum/genética , Saccharum/metabolismo
10.
Curr Protein Pept Sci ; 23(1): 6-19, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34951361

RESUMEN

Antimicrobial Peptides (AMPs) are small, ribosomally synthesized proteins found in nearly all forms of life. In plants, AMPs play a central role in plant defense due to their distinct physicochemical properties. Due to their broad-spectrum antimicrobial activity and rapid killing action, plant AMPs have become important candidates for the development of new drugs to control plant and animal pathogens that are resistant to multiple drugs. Further research is required to explore the potential uses of these natural compounds. Computational strategies have been increasingly used to understand key aspects of antimicrobial peptides. These strategies will help to minimize the time and cost of "wet-lab" experimentation. Researchers have developed various tools and databases to provide updated information on AMPs. However, despite the increased availability of antimicrobial peptide resources in biological databases, finding AMPs from plants can still be a difficult task. The number of plant AMP sequences in current databases is still small and yet often redundant. To facilitate further characterization of plant AMPs, we have summarized information on the location, distribution, and annotations of plant AMPs available in the most relevant databases for AMPs research. We also mapped and categorized the bioinformatics tools available in these databases. We expect that this will allow researchers to advance in the discovery and development of new plant AMPs with potent biological properties. We hope to provide insights to further expand the application of AMPs in the fields of biotechnology, pharmacy, and agriculture.


Asunto(s)
Péptidos Catiónicos Antimicrobianos , Biología Computacional , Animales , Péptidos Catiónicos Antimicrobianos/química , Péptidos Antimicrobianos , Bases de Datos Factuales , Plantas/genética , Plantas/metabolismo
11.
Pharmaceutics ; 13(6)2021 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-34064302

RESUMEN

Bacterial resistance has intensified in recent years due to the uncontrolled use of conventional drugs, and new bacterial strains with multiple resistance have been reported. This problem may be solved by using antimicrobial peptides (AMPs), which fulfill their bactericidal activity without developing much bacterial resistance. The rapid interaction between AMPs and the bacterial cell membrane means that the bacteria cannot easily develop resistance mechanisms. In addition, various drugs for clinical use have lost their effect as a conventional treatment; however, the synergistic effect of AMPs with these drugs would help to reactivate and enhance antimicrobial activity. Their efficiency against multi-resistant and extensively resistant bacteria has positioned them as promising molecules to replace or improve conventional drugs. In this review, we examined the importance of antimicrobial peptides and their successful activity against critical and high-priority bacteria published in the WHO list.

12.
Biochim Biophys Acta Biomembr ; 1863(4): 183551, 2021 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-33465367

RESUMEN

The cytoplasmic membrane is one of the most frequent cell targets of antimicrobial peptides (AMPs) and other biomolecules. Understanding the mechanism of action of AMPs at the molecular level is of utmost importance for designing of new membrane-specific molecules. In particular, the formation of pores, the structure and size of these pores are of great interest and require nanoscale resolution approaches, therefore, biophysical strategies are essential to achieve an understanding of these processes at this scale. In the case of membrane active peptides, pore formation or general membrane disruption is usually the last step before cell death, and so, pore size is generally directly associated to pore structure and stability and loss of cellular homeostasis, implicated in overall peptide activity. Up to date, there has not been a critical review discussing the methods that can be used specifically for estimating the pore dimensions induced by membrane active peptides. In this review we discuss the scope, relevance and popularity of the different biophysical techniques such as liposome leakage experiments, advanced microscopy, neutron or X-ray scattering, electrophysiological techniques and molecular dynamics studies, all of them useful for determining pore structure and dimension.


Asunto(s)
Membrana Dobles de Lípidos/química , Simulación de Dinámica Molecular , Proteínas Citotóxicas Formadoras de Poros/química , Liposomas/química
13.
BBA Adv ; 1: 100002, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-37082019

RESUMEN

Polybia-MP1 is an antimicrobial peptide that shows a decreased activity in membranes with cholesterol (CHO). Since it is now accepted that hopanoids act as sterol-surrogates in some sterol-lacking bacteria, we here inquire about the impact of Polybia-MP1 on membranes containing the hopanoid diplopterol (DP) in comparison to membranes with CHO. We found that, despite the properties induced on lipid membranes by DP are similar to those induced by CHO, the effect of Polybia-MP1 on membranes with CHO or DP was significantly different. DP did not prevent dye release from LUVs, nor the insertion of Polybia-MP1 into monolayers, and peptide-membrane affinity was higher for those with DP than with CHO. Zeta potentials ( ζ ) for DP-containing LUVs showed a complex behavior at increasing peptide concentration. The effect of the peptide on membrane elasticity, investigated by nanotube retraction experiments, showed that peptide addition softened all membrane compositions, but membranes with DP got stiffer at long times. Considering this, and the ζ results, we propose that peptides accumulate at the interface adopting different arrangements, leading to a non-monotonic behavior. Possible correlations with cell membranes were inquired testing the antimicrobial activity of Polybia-MP1 against hopanoid-lacking bacteria pre-incubated with DP or CHO. The fraction of surviving cells was lower in cultures incubated with DP compared to those incubated with CHO. We propose that the higher activity of Polybia-MP1 against some bacteria compared to mammalian cells is not only related to membrane electrostatics, but also the composition of neutral lipids, particularly the hopanoids, could be important.

14.
Insects ; 11(7)2020 Jul 08.
Artículo en Inglés | MEDLINE | ID: mdl-32650366

RESUMEN

Lotmaria passim currently appears to be the predominant trypanosome in honey bees worldwide. Although, the specific effects of L. passim by single or mixed with other gut parasites such as Nosema ceranae on honey bees' health is still unclear. We consequently measured bees' survival, parasite loads, the expression of antimicrobial peptides (AMPs) and vitellogenin gene. Thus, (1) bees naturally infected with L. passim, (2) healthy bees inoculated with Nosema ceranae, (3) bees naturally infected with L. passim and inoculated with N. ceranae and (4) healthy bees (control) were maintained under controlled conditions. Honey bees infected with N. ceranae or with mixed infections of L. passim and N. ceranae had significantly lower survival rates than the control group at 20 days post-inoculation (dpi). A competitive suppression was also detected, provided that the L. passim load was significantly affected by the presence of N. ceranae at 15 dpi. Expressions of the AMPs defensin and hymenoptaecin rapidly (two hours post-inoculation) increased in bees infected with N. ceranae and mixed infections. However, this effect was not continuous. In fact, expressions of abaecin, defensin, hymenoptaecin and vitellogenin decreased drastically at 15 dpi in bees with both single and mixed infections. The decrease in the expression of AMPs and vitellogenin throughout this period was consistent with the reduced survivals observed in this study, indicating that mixed infections of L. passim and N. ceranae, and even into a scenario of competition between them, may have a synergic effect on the survival and immune-related gene expressions (biomarkers) of worker bees.

15.
Curr Protein Pept Sci ; 21(5): 527-541, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31951167

RESUMEN

Antimicrobial peptides (AMPs) have been found in all organism taxa and may play an essential role as a host defense system. AMPs are organized in various conformations, such as linear peptides, disulfide bond-linked peptides, backbone-linked peptides and circular peptides. AMPs apparently act primarily on the plasma membrane, although an increasing number of works have shown that they may also target various intracellular sites. Spider venoms are rich sources of biomolecules that show several activities, including modulation or blockage of ion channels, anti-insect, anti-cancer, antihypertensive and antimicrobial activities, among others. In spider venoms from the Lycosidae family there are many linear AMPs with a wide range of activities against several microorganisms. Due to these singular activities, some Lycosidae AMPs have been modified to improve or decrease desirable or undesirable effects, respectively. Such modifications, especially with the aim of increasing their antibiotic activity, have led to the filing of many patent applications. This review explores the abundance of Lycosidae venom AMPs and some of their derivatives, and their use as new drug models.


Asunto(s)
Antiinfecciosos/química , Antihipertensivos/química , Péptidos Catiónicos Antimicrobianos/química , Antineoplásicos/química , Moduladores del Transporte de Membrana/química , Arañas/química , Secuencia de Aminoácidos , Animales , Antiinfecciosos/aislamiento & purificación , Antiinfecciosos/farmacología , Antihipertensivos/aislamiento & purificación , Antihipertensivos/farmacología , Péptidos Catiónicos Antimicrobianos/aislamiento & purificación , Péptidos Catiónicos Antimicrobianos/farmacología , Antineoplásicos/aislamiento & purificación , Antineoplásicos/farmacología , Membrana Celular/efectos de los fármacos , Eritrocitos/citología , Eritrocitos/efectos de los fármacos , Expresión Génica , Hemólisis/efectos de los fármacos , Humanos , Moduladores del Transporte de Membrana/aislamiento & purificación , Moduladores del Transporte de Membrana/farmacología , Peso Molecular , Patentes como Asunto , Conejos , Venenos de Araña/química , Arañas/fisiología
16.
Front Cell Infect Microbiol ; 10: 612931, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-33614528

RESUMEN

Bacterial infections caused by intracellular pathogens are difficult to control. Conventional antibiotic therapies are often ineffective, as high doses are needed to increase the number of antibiotics that will cross the host cell membrane to act on the intracellular bacterium. Moreover, higher doses of antibiotics may lead to elevated severe toxic effects against host cells. In this context, antimicrobial peptides (AMPs) and cell-penetrating peptides (CPPs) have shown great potential to treat such infections by acting directly on the intracellular pathogenic bacterium or performing the delivery of cargos with antibacterial activities. Therefore, in this mini-review, we cover the main AMPs and CPPs described to date, aiming at intracellular bacterial infection treatment. Moreover, we discuss some of the proposed mechanisms of action for these peptide classes and their conjugation with other antimicrobials.


Asunto(s)
Infecciones Bacterianas , Péptidos de Penetración Celular , Antibacterianos/farmacología , Péptidos Catiónicos Antimicrobianos/farmacología , Infecciones Bacterianas/tratamiento farmacológico , Humanos , Proteínas Citotóxicas Formadoras de Poros
17.
Gels ; 5(1)2019 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-30769870

RESUMEN

Relatively smaller volumes of gelling systems had been used to address conformance problems located near the wellbore in oil reservoirs with harsh temperature and salinity conditions. These gelling systems were formulated with high concentrations of low-molecular-weight acrylamide-based polymers crosslinked with polyethylenimine (PEI). However, for in-depth conformance control, in which large gelant volumes and long gelation times were required, lower-base polymer loadings were necessary to ensure the economic feasibility of the treatment. In this study, a gelling system with high-molecular weight 2-acrylamido-2-methylpropane sulfonic acid (AMPS), N-vinyl-2-pyrrolidone (NVP), acrylamide terpolymer, and PEI, with the addition of bentonite as a filler, was formulated. The influence of the gelant formulation and reservoir conditions on the gelation kinetics and final gel strength of the system was investigated through bottle tests and rheological tests. The addition of clay in the formulation increased the gelation time, thermal stability, and syneresis resistance, and slightly improved the final gel strength. Furthermore, samples prepared with polymer and PEI concentrations below 1 wt %, natural bentonite, and PEI with molecular weight of 70,000 kg/kmol and pH of 11: (i) presented good injectivity and propagation parameters (pseudoplastic behavior and viscosity ~25 mPa·s); (ii) showed suitable gelation times for near wellbore (~5 h) or far wellbore (~21 h) treatments; and (iii) formed strong composite hydrogels (equilibrium complex modulus ~10⁻20 Pa and Sydansk code G to H) with low syneresis and good long-term stability (~3 to 6 months) under harsh conditions. Therefore, the use of high-molecular-weight base polymer and low-cost clay as active filler seems promising to improve the cost-effectiveness of gelling systems for in-depth conformance treatments under harsh conditions of temperature and salinity/hardness.

18.
Protein Pept Lett ; 26(2): 98-107, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-30605048

RESUMEN

Antimicrobial resistance is a global health problem with strong social and economic impacts. The development of new antimicrobial agents is considered an urgent challenge. In this regard, Antimicrobial Peptides (AMPs) appear to be novel candidates to overcome this problem. The mechanism of action of AMPs involves intracellular targets and membrane disruption. Although the exact mechanism of action of AMPs remains controversial, most AMPs act through membrane disruption of the target cell. Several strategies have been used to improve AMP activity, such as peptide dimerization. In this review, we focus on AMP dimerization, showing many examples of dimerized peptides and their effects on biological activity. Although more studies are necessary to elucidate the relationship between peptide properties and the dimerization effect on antimicrobial activity, dimerization constitutes a promising strategy to improve the effectiveness of AMPs.


Asunto(s)
Antiinfecciosos/farmacología , Péptidos Catiónicos Antimicrobianos/farmacología , Multimerización de Proteína , Animales , Transporte Biológico , Membrana Celular/efectos de los fármacos , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Relación Estructura-Actividad
19.
J Pediatr ; 197: 172-176, 2018 06.
Artículo en Inglés | MEDLINE | ID: mdl-29625732

RESUMEN

OBJECTIVES: To evaluate the healthcare use and costs of amplified musculoskeletal pain syndrome (AMPS) in children before diagnosis. STUDY DESIGN: We performed a retrospective study in children with AMPS at a pediatric rheumatology clinic between 2010 and 2014. Data were abstracted on 80 patients after primary rheumatic diseases were excluded. Healthcare visits, medications and diagnostic testing that occurred in the years before diagnosis were collected. The Medical Expenditure Panel Survey was used to estimate visit costs. RESULTS: Patients were adolescent females (89%) and white (86%). The median time to diagnosis was 10.2 months. The median pain score was 6.5 and the median Childhood Health Assessment Questionnaire score was 1.1. In this cohort, 29% had at least 1 ED visit and 5% were hospitalized. All patients saw a rheumatologist and 41% had visited another specialist, typically orthopedics and sports medicine. More than one-half had at least 1 radiographic study and 21% had at least 1 magnetic resonance imaging. The total cost for office, emergency department, and hospital visits for AMPS in all 80 patients was $152 853. The mean cost per patient over the entire study period (2008-2014) was $1911 ± $3808, and 43% of costs were outpatient visits. CONCLUSIONS: Children with AMPS have high levels of disability and take a long time to be diagnosed. As a result, even before diagnosis, they have high levels of healthcare use, diagnostic testing, and medical costs. Early recognition of disability and quicker referral to trained subspecialists may improve the prognosis, reduce unnecessary testing, and reduce the overall costs of healthcare.


Asunto(s)
Dolor Crónico/terapia , Costo de Enfermedad , Costos de la Atención en Salud/estadística & datos numéricos , Dolor Musculoesquelético/terapia , Aceptación de la Atención de Salud/estadística & datos numéricos , Adolescente , Femenino , Humanos , Masculino , Dolor Musculoesquelético/economía , Dimensión del Dolor , Estudios Retrospectivos , Encuestas y Cuestionarios
20.
Front Immunol ; 8: 339, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28424688

RESUMEN

While mesenchymal stem cells (MSCs)-based therapy appears to be promising, there are concerns regarding possible side effects related to the unwanted suppression of antimicrobial immunity leading to an increased risk of infection. Conversely, recent data show that MSCs exert strong antimicrobial effects through indirect and direct mechanisms, partially mediated by the secretion of antimicrobial peptides and proteins (AMPs). In fact, MSCs have been reported to increase bacterial clearance in preclinical models of sepsis, acute respiratory distress syndrome, and cystic fibrosis-related infections. This article reviews the current evidence regarding the direct antimicrobial effector function of MSCs, focusing mainly on the role of MSCs-derived AMPs. The strategies that might modulate the expression and secretion of these AMPs, leading to enhanced antimicrobial effect, are highlighted. Furthermore, studies evaluating the presence of AMPs in the cargo of extracellular vesicles (EVs) are underlined as perspective opportunities to develop new drug delivery tools. The antimicrobial potential of MSCs-derived EVs can also be heightened through cell conditioning and/or drug loading. Finally, improving the pharmacokinetics and delivery, in addition to deciphering the multi-target drug status of AMPs, should synergistically lead to key advances against infections caused by drug-resistant strains.

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