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1.
Vaccine ; 42(4): 972-986, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38135642

RESUMO

Vaccine Benefit-Risk (B-R) assessment consists of evaluating the benefits and risks of a vaccine and making a judgment whether the expected key benefits outweigh the potential key risks associated with its expected use. B-R supports regulatory and public health decision-making throughout the vaccine's lifecycle. In August 2021, the Brighton Collaboration's Benefit-Risk Assessment of VAccines by TechnolOgy (BRAVATO) Benefit-Risk Assessment Module working group was established to develop a standard module to support the planning, conduct and evaluation of structured B-R assessments for vaccines from different platforms, based on data from clinical trials, post-marketing studies and real-world evidence. It enables sharing of relevant information via value trees, effects tables and graphical depictions of B-R trade-offs. It is intended to support vaccine developers, funders, regulators and policy makers in high-, middle- or low-income countries to help inform decision-making and facilitate transparent communication concerning development, licensure, deployment and other lifecycle decisions.


Assuntos
Vacinas , Medição de Risco , Vacinas/efeitos adversos , Humanos
2.
J Alzheimers Dis ; 96(1): 351-358, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37781803

RESUMO

BACKGROUND: Pork provides higher levels of several nutrients important for cognitive maintenance in older adults. A pilot clinical study suggests the addition of moderate amounts of pork to a Mediterranean-style diet improves cognition in older adults. There is an absence of observational research that isolates effects of pork from other red meats. OBJECTIVE: To examine the relationship of pork intake on cognitive performance in older adults. METHODS: Cross-sectional data from the U.S. National Health and Nutrition Examination Survey (NHANES) 2011-2014 cycles were used in these analyses. Pork intake was assessed using data from two non-consecutive 24-h dietary recalls. Cognitive function was assessed by the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) Word Learning, CERAD Delayed Recall, Animal Fluency, and Digital Substitution tests. Statistical analyses were adjusted for sample weighting and survey design variables to account for the complex design. Student t-tests (continuous variables) and Pearson chi-squared tests (categorical variables) were employed to compare participant characteristics between the low and normal cognitive performance groups. Logistic regression was used to determine the relationship of pork intake (low, medium, and high) with prevalence of low cognitive performance, with the non-consumer group as the referent category. RESULTS: Pork intake was not beneficially or detrimentally associated performance on the any of the cognitive tests in both the crude and multivariate models (p > 0.05). CONCLUSIONS: Prospective cohort investigations and larger/longer-term clinical trials are needed to fully elucidate effects of pork intake on cognition in older adults.


Assuntos
Doença de Alzheimer , Carne de Porco , Carne Vermelha , Animais , Humanos , Suínos , Idoso , Inquéritos Nutricionais , Estudos Transversais , Estudos Prospectivos , Cognição
3.
Nutrients ; 15(11)2023 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-37299558

RESUMO

Pork has the potential to provide several macro and micronutrients to the diet, as it is a commonly consumed protein in the United States and across many cultures worldwide. There is an absence of clinical and observational studies that isolate the nutritional contribution of various types of pork intake from that of other red and/or processed meats. The objective of this study was to assess consumption patterns and the nutritional contribution of total, processed, fresh, and fresh-lean pork to the diets of participants aged 2+ years enrolled in the National Health and Nutrition Examination Survey (NHANES) 2007-2018 data cycles. The recent National Cancer Institute method was used to disaggregate fresh and processed pork intake from the USDA Food Patterns Equivalents Database. The mean intake of total pork among consumers was estimated to be 79.5 ± 0.82, 54.2 ± 0.69, 54.6 ± 0.93, and 45.9 ± 0.73, g/d for men, women, boys, and girls, respectively. Total pork consumption subtly increased intakes of total energy and several macro and micronutrients, decreased diet quality (HEI-2015) scores (adults only), and consumption of other "healthful" food groups. Only subtle but clinically insignificant effects of pork intake on biomarkers of nutritional status were shown. These trends were largely driven by processed pork consumption and the co-consumption of foods such as condiments. Increasing the availability and education around fresh-lean cuts may help to increase intake of protein and other key nutrients across certain subpopulations, without adversely affecting diet quality and biomarkers of health status.


Assuntos
Dieta , Carne de Porco , Adulto , Animais , Feminino , Humanos , Masculino , Ingestão de Energia , Comportamento Alimentar , Micronutrientes , Inquéritos Nutricionais , Suínos , Estados Unidos , Criança
7.
Peptides ; 97: 22-28, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-28951157

RESUMO

The Mexican burrowing toad Rhinophrynus dorsalis is the sole extant representative of the Rhinophrynidae. United in the superfamily Pipoidea, the Rhinophrynidae is considered to be the sister-group to the extant Pipidae which comprises Hymenochirus, Pipa, Pseudhymenochirus and Xenopus. Cationic, α-helical host-defense peptides of the type found in Hymenochirus, Pseudhymenochirus, and Xenopus species (hymenochirins, pseudhymenochirins, magainins, and peptides related to PGLa, XPF, and CPF) were not detected in norepinephrine-stimulated skin secretions of R. dorsalis. Skin secretions of representatives of the genus Pipa also do not contain cationic α-helical host-defense peptides which suggest, as the most parsimonious hypothesis, that the ability to produce such peptides by frogs within the Pipidae family arose in the common ancestor of (Hymenochirus+Pseudhymenochirus)+Xenopus after divergence from the line of evolution leading to extant Pipa species. Peptidomic analysis of the R. dorsalis secretions led to the isolation of rhinophrynin-27, a proline-arginine-rich peptide with the primary structure ELRLPEIARPVPEVLPARLPLPALPRN, together with rhinophrynin-33 containing the C-terminal extension KMAKNQ. Rhinophrynin-27 shows limited structural similarity to the porcine multifunctional peptide PR-39 but it lacks antimicrobial and cytotoxic activities. Like PR-39, the peptide adopts a poly-l-proline helix but some changes in the circular dichroism spectrum were observed in the presence of anionic sodium dodecylsulfate micelles consistent with the stabilization of turn structures.


Assuntos
Proteínas de Anfíbios/química , Peptídeos Catiônicos Antimicrobianos/química , Pipidae/fisiologia , Pele/metabolismo , Células A549 , Sequência de Aminoácidos , Proteínas de Anfíbios/isolamento & purificação , Proteínas de Anfíbios/metabolismo , Proteínas de Anfíbios/farmacologia , Animais , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/farmacologia , Arginina/química , Bactérias/efeitos dos fármacos , Dicroísmo Circular , Humanos , Micelas , Prolina/química , Proteômica , Dodecilsulfato de Sódio/química
8.
Vaccine ; 34(49): 6038-6046, 2016 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-27491687

RESUMO

Maternal vaccination is an important area of research and requires appropriate and internationally comparable definitions and safety standards. The GAIA group, part of the Brighton Collaboration was created with the mandate of proposing standardised definitions applicable to maternal vaccine research. This study proposes international definitions for neonatal infections. The neonatal infections GAIA working group performed a literature review using Medline, EMBASE and the Cochrane collaboration and collected definitions in use in neonatal and public health networks. The common criteria derived from the extensive search formed the basis for a consensus process that resulted in three separate definitions for neonatal blood stream infections (BSI), meningitis and lower respiratory tract infections (LRTI). For each definition three levels of evidence are proposed to ensure the applicability of the definitions to different settings. Recommendations about data collection, analysis and presentation are presented and harmonized with the Brighton Collaboration and GAIA format and other existing international standards for study reporting.


Assuntos
Controle de Doenças Transmissíveis , Imunização/efeitos adversos , Infecções/epidemiologia , Vacinas/efeitos adversos , Bacteriemia/epidemiologia , Bacteriemia/prevenção & controle , Coleta de Dados , Feminino , Humanos , Recém-Nascido , Meningite/epidemiologia , Meningite/prevenção & controle , Sepse/epidemiologia , Sepse/prevenção & controle , Estatística como Assunto
9.
J Nat Prod ; 79(9): 2350-6, 2016 09 23.
Artigo em Inglês | MEDLINE | ID: mdl-27560386

RESUMO

Four host-defense peptides belonging to the tigerinin family (tigerinin-1O: RICTPIPFPMCY; tigerinin-2O: RTCIPIPLVMC; tigerinin-3O: RICTAIPLPMCL; and tigerinin-4O: RTCIPIPPVCF) were isolated from skin secretions of the African crowned bullfrog Hoplobatrachus occipitalis. In aqueous solution at pH 4.8, the cyclic domain of tigerinin-2O adopts a rigid amphipathic conformation that incorporates a flexible N-terminal tail. The tigerinins lacked antimicrobial (MIC > 100 µM) and hemolytic (LC50 > 500 µM) activities but, at a concentration of 20 µg/mL, significantly (P < 0.05) inhibited production of interferon-γ (IFN-γ) by peritoneal cells from C57BL/6 mice without affecting production of IL-10 and IL-17. Tigerinin-2O and -4O inhibited IFN-γ production at concentrations as low as 1 µg/mL. The tigerinins significantly (P ≤ 0.05) stimulated the rate of insulin release from BRIN-BD11 clonal ß-cells without compromising the integrity of the plasma membrane. Tigerinin-1O was the most potent (threshold concentration 1 nM) and the most effective (395% increase over basal rate at a concentration of 1 µM). Tigerinin-4O was the most potent and effective peptide in stimulating the rate of glucagon-like peptide-1 release from GLUTag enteroendocrine cells (threshold concentration 10 nM; 289% increase over basal rate at 1 µM). Tigerinin peptides have potential for development into agents for the treatment of patients with type 2 diabetes.


Assuntos
Proteínas de Anfíbios/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos/farmacologia , Pele/metabolismo , Proteínas de Anfíbios/química , Proteínas de Anfíbios/farmacologia , Animais , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Diabetes Mellitus Tipo 2/tratamento farmacológico , Humanos , Concentração de Íons de Hidrogênio , Insulina/farmacologia , Interleucina-10/metabolismo , Interleucina-17/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Testes de Sensibilidade Microbiana , Peptídeos/química , Peptídeos/isolamento & purificação , Rana catesbeiana , Pele/efeitos dos fármacos
10.
Artigo em Inglês | MEDLINE | ID: mdl-27290612

RESUMO

The Uganda clawed frog Xenopus ruwenzoriensis with a karyotype of 2n=108 is one of the very few vertebrates with dodecaploid status. Peptidomic analysis of norepinephrine-stimulated skin secretions from this species led to the isolation and structural characterization of 23 host-defense peptides belonging to the following families: magainin (3 peptides), peptide glycine-leucine-amide (PGLa; 6 peptides), xenopsin precursor fragment (XPF; 3 peptides), caerulein precursor fragment (CPF; 8 peptides), and caerulein precursor fragment-related peptide (CPF-RP; 3 peptides). In addition, the secretions contained caerulein, identical to the peptide from Xenopus laevis, and two peptides that were identified as members of the trefoil factor family (TFF). The data indicate that silencing of the host-defense peptide genes following polyploidization has been appreciable and non-uniform. Consistent with data derived from comparison of nucleotide sequences of mitochrondrial and nuclear genes, cladistic analyses based upon the primary structures of the host-defense peptides provide support for an evolutionary scenario in which X. ruwenzoriensis arose from an allopolyploidization event involving an octoploid ancestor of the present-day frogs belonging to the Xenopus amieti species group and a tetraploid ancestor of Xenopus pygmaeus.


Assuntos
Norepinefrina/farmacologia , Fragmentos de Peptídeos/análise , Pipidae/metabolismo , Pele/metabolismo , Proteínas de Xenopus/metabolismo , Animais , Evolução Molecular , Fragmentos de Peptídeos/isolamento & purificação , Pele/efeitos dos fármacos , Vasoconstritores/farmacologia
11.
Peptides ; 72: 44-9, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25849343

RESUMO

Peptidomic analysis of norepinephrine-stimulated skin secretions from the octoploid Mawa clawed frog Xenopus boumbaensis Loumont, 1983 led to the identification and characterization of 15 host-defense peptides belonging to the magainin (two peptides), peptide glycine-leucine-amide (PGLa; three peptides), xenopsin precursor fragment (XPF; three peptides), caerulein precursor fragment (CPF; two peptides), and caerulein precursor fragment-related peptide (CPF-RP; five peptides) families. In addition, caerulein and three peptides with structural similarity to the trefoil factor family (TFF) peptides, xP2 and xP4 from Xenopus laevis were also present in the secretions. Consistent with data from comparisons of the nucleotides sequence of mitochondrial and nuclear genes, the primary structures of the peptides suggest a close phylogenetic relationship between X. boumbaensis and the octoploid frogs Xenopus amieti and Xenopus andrei. As the three species occupy disjunct ranges within Cameroon, it is suggested that they diverged from a common ancestor by allopatric speciation.


Assuntos
Proteínas de Anfíbios/química , Peptídeos/química , Pele/metabolismo , Proteínas de Anfíbios/genética , Proteínas de Anfíbios/metabolismo , Animais , Peptídeos/genética , Peptídeos/metabolismo , Fator Trefoil-2 , Xenopus
12.
Psychophysiology ; 52(1): 8-19, 2015 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-25252169

RESUMO

Skin conductance (SC) reflects stimulus significance and can be measured by integrating electrodes directly onto a smartphone housing such that they are naturally contacted when gripped. However, grip artifacts naturally arise during operation since grip forces can vary. We explored the effects of grip force on SC to determine feasibility and to draw guidelines on artifact mitigation. For this purpose, a prototype was built with integrated SC electrodes with colocated force sensors, and data was collected from 24 participants gripping the prototype across different grip force conditions. Our analysis showed that static forces greater than 2.0 N were associated with significant SC distortion, and artifacts induced from dynamic grip forces were buffered if the SC level was at least 1.1 microsiemens. Our findings are relevant for future applications of SC sensing on smartphones, which may enable interesting and highly contextual user experiences.


Assuntos
Computadores de Mão , Eletrodos , Resposta Galvânica da Pele/fisiologia , Força da Mão/fisiologia , Monitorização Ambulatorial/instrumentação , Adolescente , Adulto , Estudos de Viabilidade , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Smartphone , Adulto Jovem
13.
Peptides ; 56: 132-40, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24704757

RESUMO

Peptidomic analysis of norepinephrine-stimulated skin secretions of the Orinoco lime tree frog Sphaenorhynchus lacteus (Hylidae, Hylinae) revealed the presence of three structurally related host-defense peptides with limited sequence similarity to frenatin 2 from Litoria infrafrenata (Hylidae, Pelodryadinae) and frenatin 2D from Discoglossus sardus (Alytidae). Frenatin 2.1S (GLVGTLLGHIGKAILG.NH2) and frenatin 2.2S (GLVGTLLGHIGKAILS.NH2) are C-terminally α-amidated but frenatin 2.3S (GLVGTLLGHIGKAILG) is not. Frenatin 2.1S and 2.2S show potent bactericidal activity against clinical isolates of methicillin-resistant Staphylococcus aureus (MRSA) and Staphylococcus epidermidis (MIC ≤16µM) but are less active against a range of Gram-negative bacteria. Frenatin 2.1S (LC50=80±6 µM) and 2.2S (LC50=75±5 µM) are cytotoxic against non-small cell lung adenocarcinoma A549 cells but are less hemolytic against human erythrocytes (LC50=167±8 µM for frenatin 2.1S and 169±7 µM for 2.2S). Weak antimicrobial and cytotoxic potencies of frenatin 2.3S demonstrate the importance of C-terminal α-amidation for activity. Frenatin 2.1S and 2.2S significantly (P<0.05) increased production of proinflammatory cytokines IL-1ß and IL-23 by lipopolysaccharide (LPS)-stimulated mouse peritoneal macrophages and frenatin 2.1S also enhanced production of TNF-α. Effects on IL-6 production were not significant. Frenatin 2.2S significantly downregulated production of the anti-inflammatory cytokine IL-10 by LPS-stimulated cells. The data support speculation that frenatins act on skin macrophages to produce a cytokine-mediated stimulation of the adaptive immune system in response to invasion by microorganisms. They may represent a template for the design of peptides with therapeutic applications as immunostimulatory agents.


Assuntos
Anti-Infecciosos/farmacologia , Fatores Imunológicos/farmacologia , Peptídeos/química , Peptídeos/farmacologia , Pele/metabolismo , Proteínas de Anfíbios/química , Animais , Anti-Infecciosos/química , Antineoplásicos/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Humanos , Fatores Imunológicos/química , Interleucina-10/metabolismo , Interleucina-1beta/metabolismo , Interleucina-23/metabolismo , Lipopolissacarídeos/farmacologia , Macrófagos/efeitos dos fármacos , Macrófagos/metabolismo , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Fator de Necrose Tumoral alfa/metabolismo
14.
Artigo em Inglês | MEDLINE | ID: mdl-24463457

RESUMO

The primary structures of host-defense peptides present in frog skin secretions constitute useful molecular markers for establishing taxonomic classifications and investigating phylogenetic relationships between species within a particular genus. Peptidomic analysis has led to the characterization of multiple host-defense peptides in norepinephrine-stimulated skin secretions of three species of frogs from the family Ranidae: Lithobates forreri (Boulenger, 1883), Hylarana luctuosa (Peters, 1871), and Hylarana signata (Günther, 1872). The L. forreri secretions contain ranatuerin-2 (2 peptides), brevinin-1 (4 peptides), and temporin (1 peptide). The H. luctuosa secretions contain brevinin-2 (4 peptides), esculentin-1 (1 peptide), esculentin-2 (1 peptide), palustrin-2 (2 peptides), and temporin (2 peptides). The H. signata secretions contain brevinin-2 (4 peptides), brevinin-1 (5 peptides), palustrin-2 (1 peptide), and temporin (2 peptides). Cladistic analysis based upon the primary structures of 44 ranatuerin-2 peptides from 20 Lithobates species indicates a close phylogenetic relationship between L. forreri, Lithobates onca, and Lithobates yavapaiensis. A similar cladistic analysis based upon the primary structures of 27 brevinin-2 peptides from 8 Hylarana species provides support for a close phylogenetic relationship between H. signata and Hylarana picturata, while showing that the species are not conspecific, with H. luctuosa more distantly related.


Assuntos
Proteínas de Anfíbios/química , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Proteínas/química , Ranidae/genética , Sequência de Aminoácidos , Proteínas de Anfíbios/genética , Proteínas de Anfíbios/isolamento & purificação , Proteínas de Anfíbios/farmacologia , Animais , Antibacterianos/isolamento & purificação , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/genética , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Infecções Bacterianas/tratamento farmacológico , Masculino , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Filogenia , Proteínas/genética , Proteínas/isolamento & purificação , Proteínas/farmacologia , Pele/química
15.
Artigo em Inglês | MEDLINE | ID: mdl-24212286

RESUMO

The family Pipidae comprises the genera Hymenochirus, Pipa, Pseudhymenochirus, Silurana, and Xenopus but phylogenetic relationships within the family are unclear. Peptidomic analysis of norepinephrine-stimulated skin secretions from Pseudhymenochirus merlini Chabanaud, 1920, the single species within the genus Pseudhymenochirus, led to identification of 13 host-defense peptides with antimicrobial activity. Two peptides (hymenochirin-1Pa and -1Pb) show structural similarity to hymenochirin-1B from Hymenochirus boettgeri and eight peptides (hymenochirin-5Pa, -5Pb, -5Pc, -5Pd, -5Pe, -5Pf, 5Pg and -5Ph) are structurally similar to each other and to hymenochirin-5B from H. boettgeri. Two peptides differing by a single amino acid (IKIPSFFRNILKKVGKEAVSLM/I AGALKQS), termed pseudhymenochirin-1Pa and -1Pb, and pseudhymenochirin-2Pa (GIFPIFAKLLGKVIKVASSLISKGRTE) do not resemble host-defense peptides previously isolated from pipid frogs. Hymenochirin-5Pe was the most abundant peptide in the secretions and hymenochirin-1Pa the most potent against Staphylococcus aureus (MIC=2.5µM) and Escherichia coli (MIC=10µM). The data support a close phylogenetic relationship between Hymenochirus and Pseudhymenochirus that is distinct from the Xenopodinae (Xenopus+Silurana) clade with Pipa sister-group to all other extant pipids.


Assuntos
Proteínas de Anfíbios/química , Peptídeos Catiônicos Antimicrobianos/química , Pipidae/metabolismo , Pele/metabolismo , Xenopus/classificação , Sequência de Aminoácidos , Proteínas de Anfíbios/farmacologia , Animais , Peptídeos Catiônicos Antimicrobianos/farmacologia , Fenômenos Químicos , Escherichia coli/efeitos dos fármacos , Filogenia , Pipidae/classificação , Staphylococcus aureus/efeitos dos fármacos , Xenopus/genética , Xenopus/metabolismo
16.
Artigo em Inglês | MEDLINE | ID: mdl-23896465

RESUMO

Peptidomic analysis was used to compare the distribution of host-defense peptides in norepinephrine-stimulated skin secretions from Xenopus victorianusAhl, 1924 (also described as the subspecies X. laevis victorianus) and Xenopus laevis sudanensisPerret, 1966 with the previously determined distributions in Xenopus laevis (Daudin, 1802) and Xenopus petersii Bocage, 1895. Peptides belonging to the magainin, peptide glycine-leucine-amide (PGLa), and caerulein precursor fragment (CPF) families were purified by reversed-phase HPLC and characterized by electrospray mass spectrometry. Magainin-P2, PGLa-P1, CPF-P1, CPF-P2, and CPF-P3 previously isolated from X. petersii and structurally different from orthologous peptides from X. laevis, were identified in X. victorianus and X. laevis sudanensis skin secretions whereas the corresponding X. laevis peptides were absent. Magainin-1, identical in X. petersii and X. laevis, was also identified in the secretions. Xenopsin-precursor fragment (XPF) peptides, absent from X. petersii but present in X. laevis skin secretions, were not identified in the X. victorianus and X. laevis sudanensis secretions. The data indicate that X. victorianus and X. laevis sudanensis are more closely related to X. petersii than to X. laevis and support separate species status. The study illustrates the value of analysis of host-defense peptides in the evaluation of taxonomic and phylogenetic relationships between closely related frog species.


Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Pele/metabolismo , Proteínas de Xenopus/metabolismo , Xenopus/classificação , Sequência de Aminoácidos , Animais , Peptídeos Catiônicos Antimicrobianos/química , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Feminino , Masculino , Dados de Sequência Molecular , Peso Molecular , Alinhamento de Sequência , Espectrometria de Massas por Ionização por Electrospray , Xenopus/metabolismo , Proteínas de Xenopus/química , Xenopus laevis/classificação , Xenopus laevis/metabolismo
17.
Peptides ; 37(1): 113-9, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22800690

RESUMO

A putative genome duplication event within the Silurana lineage has given rise to the tetraploid Cameroon clawed frog Silurana epitropicalis (Fischberg, Colombelli, and Picard, 1982). Peptidomic analysis of norepinephrine-stimulated skin secretions of S. epitropicalis led to identification of 10 peptides with varying degrees of growth-inhibitory activity against Escherichia coli and Staphylococcus aureus. Structural characterization identified the peptides as belonging to the magainin family (magainin-SE1), the caerulein-precursor fragment family (CPF-SE1, -SE2 and -SE3), the xenopsin-precursor fragment family (XPF-SE1, SE-2, SE-3 and -SE4), and the peptide glycine-leucine-amide family (PGLa-SE1 and -SE2). In addition, peptide phenylalanine-glutamine-amide (FLGALLGPLMNLLQ·NH(2)) was isolated from the secretions that lacked antimicrobial activity. Comparison of the multiplicity of orthologous peptides in S. epitropicalis and the diploid Silurana tropicalis indicates that extensive nonfunctionalization (deletion or silencing) of antimicrobial peptide genes has occurred after polyploidization in the Silurana lineage, as in the Xenopus lineage. CPF-SE2 (GFLGPLLKLGLKGAAKLLPQLLPSRQQ; MIC=2.5µM) and CPF-SE3 (GFLGSLLKTGLKVGSNLL·NH(2); MIC=5µM) showed potent growth-inhibitory activity against a range of clinical isolates of methicillin-resistant S. aureus (MRSA). Their utility as systemic anti-infective drugs is limited by significant hemolytic activity against human erythrocytes (LC(50)=50µM for CPF-SE2 and 220µM for CPF-SE3) but the peptides may find application as topical agents in treatment of MRSA skin infections and decolonization of MRSA carriers.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Pele/metabolismo , Proteínas de Xenopus/farmacologia , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/metabolismo , Eritrócitos/efeitos dos fármacos , Feminino , Hemólise , Humanos , Masculino , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Lactogênio Placentário , Estrutura Secundária de Proteína , Análise de Sequência de Proteína , Tetraploidia , Xenopus , Proteínas de Xenopus/química , Proteínas de Xenopus/isolamento & purificação , Proteínas de Xenopus/metabolismo
18.
Peptides ; 35(2): 269-75, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22497805

RESUMO

Skin secretions of frogs from the subfamily Xenopodinae (Xenopus+Silurana) within the family Pipidae are a rich source of antimicrobial peptides with therapeutic potential but species from the sister taxon Hymenochirus in the subfamily Pipinae (Hymenochirus+Pseudhymenochirus+Pipa) have not been investigated. Peptidomic analysis of norepinephrine-stimulated skin secretions from two distinct populations of the Congo dwarf clawed frog Hymenochirus boettgeri (Tornier, 1896) has led to identification of five structurally related peptides with broad-spectrum antimicrobial activity. Hymenochirin-1B (IKLSPETKDNLKKVLKGAIKGAIAVAKMV.NH(2)) is C-terminally α-amidated whereas hymenochirins-2B-5B have the general structure XKIPX(2)VKDTLKKVAKGX(2)SX(2)AGAX(3).COOH. Hymenochirin-3B (IKIPAVVKDTLKKVAKGVLSAVAGALTQ) was the most abundant peptide in the secretions. The hymenochirins show very low structural similarity with the antimicrobial peptides isolated from skin secretions of Silurana tropicalis and Xenopus laevis consistent with the proposed ancient divergence of the Pipinae and Xenopodinae. Synthetic replicates of hymenochirin-1B-4B inhibit the growth of Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, and Staphylococcus aureus (MIC in the range 10-40 µM) and Candida albicans (MIC=80 µM). The peptides display relatively weak hemolytic activity against human erythrocytes (LC(50) in the range 160 to >300 µM).


Assuntos
Anti-Infecciosos , Peptídeos Catiônicos Antimicrobianos , Pipidae/metabolismo , Sequência de Aminoácidos , Animais , Anti-Infecciosos/química , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/farmacologia , Candida albicans/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Klebsiella pneumoniae/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/efeitos dos fármacos , Alinhamento de Sequência , Pele/metabolismo , Staphylococcus aureus/efeitos dos fármacos
19.
Peptides ; 33(1): 35-43, 2012 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22123629

RESUMO

Peptidomic analysis of norepinephrine-stimulated skin secretions led to the identification of host-defense peptides belonging to the magainin, peptide glycine-leucine-amide (PGLa), and caerulein precursor fragment (CPF) families from the tetraploid frogs, Xenopus petersii (Peters' clawed frog) and Xenopus pygmaeus (Bouchia clawed frog), and the octoploid frog Xenopus lenduensis (Lendu Plateau clawed frog). Xenopsin-precursor fragment (XPF) peptides were not detected. The primary structures of the antimicrobial peptides from X. petersii demonstrate a close, but not conspecific relationship, with Xenopus laevis whereas the X. pygmaeus peptides show appreciable variation from previously characterized orthologs from other Xenopus species. Polyploidization events within the Xenopodinae (Silurana+Xenopus) are associated with extensive gene silencing (nonfunctionization) but unexpectedly the full complement of four PGLa paralogs were isolated from X. lenduendis secretions. Consistent with previous data, the CPF peptides showed the highest growth-inhibitory activity against bacteria with CPF-PG1 (GFGSLLGKALKIGTNLL.NH(2)) from X. pygmaeus combining high antimicrobial potency against Staphylococcus aureus (MIC=6 µM) with relatively low hemolytic activity (LC(50)=145 µM).


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Pele/metabolismo , Xenopus/genética , Sequência de Aminoácidos , Animais , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Ceruletídeo/química , Eritrócitos/efeitos dos fármacos , Hemolíticos/farmacologia , Humanos , Magaininas/química , Testes de Sensibilidade Microbiana , Dados de Sequência Molecular , Peptídeos/química , Poliploidia , Precursores de Proteínas/química , Staphylococcus aureus/efeitos dos fármacos , Homologia Estrutural de Proteína , Tetraploidia , Proteínas de Xenopus/química , Proteínas de Xenopus/isolamento & purificação
20.
Gen Comp Endocrinol ; 176(3): 513-8, 2012 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-22036891

RESUMO

African clawed frogs of the Xenopodinae (Xenopus+Silurana) constitute a well-defined system in which to study the evolutionary trajectory of duplicated genes and are a source of antimicrobial peptides with therapeutic potential. Allopolyploidization events within the Xenopodinae have given rise to tetraploid, octoploid, and dodecaploid species. The primary structures and distributions of host-defense peptides from the tetraploid frogs Xenopus borealis, Xenopus clivii, Xenopus laevis, Xenopus muelleri, "X. muelleri West", and Xenopus petersii may be compared with those from the octoploid frogs Xenopus amieti and X. andrei. Similarly, components in skin secretions from the diploid frog Silurana tropicalis may be compared with those from the tetraploid frog Silurana paratropicalis. All Xenopus antimicrobial peptides may be classified in the magainin, peptide glycine-leucine-amide (PGLa), caerulein-precursor fragment (CPF), and xenopsin-precursor fragment (XPF) families. However, the numbers of paralogs from the octoploid frogs were not significantly greater than the corresponding numbers from the tetraploid frogs. Magainins were not identified in skin secretions of Silurana frogs and the multiplicity of the PGLa, CPF, and XPF peptides from S. paratropicalis was not greater than that of S. tropicalis. The data indicate, therefore, that nonfunctionalization (gene silencing) has been the most common fate of antimicrobial peptide genes following polyploidization. While some duplicated gene products retain high antimicrobial potency (subfunctionalization), the very low activity of others suggests that they may be evolving towards a new biological role (neofunctionalization). CPF-AM1 and PGLa-AM1 from X. amieti show potential for development into anti-infective agents for use against antibiotic-resistant gram-negative bacteria.


Assuntos
Peptídeos Catiônicos Antimicrobianos/metabolismo , Evolução Molecular , Pipidae/metabolismo , Pele/metabolismo , Sequência de Aminoácidos , Animais , Peptídeos Catiônicos Antimicrobianos/genética , Dados de Sequência Molecular , Filogenia , Pipidae/genética , Ploidias , Alinhamento de Sequência
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