RESUMO
Staphylococcus lugdunensis produces lugdulysin, a metalloprotease that may contribute to its virulence. This study aimed to evaluate the biochemical aspects of lugdulysin and investigate its effect on Staphylococcus aureus biofilms. The protease was isolated and characterized for its optimal pH and temperature, hydrolysis kinetics, and influence of metal cofactor supplementation. The protein structure was determined via homology modeling. The effect on S. aureus biofilms was assessed by the micromethod technique. The protease optimal pH and temperature were 7.0 and 37 °C, respectively. EDTA inhibited protease activity, confirming it as a metalloprotease. Lugdulysin activity was not recovered by divalent ion supplementation post-inhibition, and supplementation with divalent ions did not change enzymatic activity. The isolated enzyme was stable for up to 3 h. Lugdulysin significantly inhibited the formation and disrupted preestablished protein-matrix MRSA biofilm. This preliminary study indicates that lugdulysin has a potential role as a competition mechanism and/or modulation of staphylococcal biofilm.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Staphylococcus lugdunensis , Humanos , Staphylococcus aureus , Antibacterianos/farmacologia , Biofilmes , Metaloproteases/farmacologia , Peptídeo Hidrolases , Testes de Sensibilidade MicrobianaRESUMO
OBJECTIVE: Depressed skull fractures are the result of trauma injuries. They are present in approximately 3% of patients who arrive to an emergency room with skull trauma. The main objective of surgical repair in depressed fractures is correction of cosmetic deformity and the prevention of infections. MATERIAL AND METHODS: A retrospective and transversal study was performed by our department between April 2016 and May 2017. Sixteen patients that underwent a craniotomy for skull trauma with depressed fracture were included in the study. The diagnosis was made by simple cranial CT scan alongside a three-dimensional reconstruction. RESULTS: Of the sixteen patients included, 5 were females (31.2%) and 11 males (68.8%). Twelve of the cases were an exposed fracture. In 7 cases, the fracture was located at parietal bone; 5 were located at frontal bone and 4 at the temporal bone. The average Glasgow coma score in the sample was 13. There were no complications nor deaths. CONCLUSIONS: The remodeling and repositioning of the autologous bone graft allow an adequate cosmetic result and it also avoids the placement of implants without increasing the costs and additional risks.
OBJETIVO: las fracturas de cráneo deprimidas son el resultado de lesiones traumáticas. Se encuentran en aproximadamente el 3% de los pacientes que se presentan en salas de emergencia con traumatismo craneal. El objetivo principal de la reparación quirúrgica en fracturas deprimidas es la corrección de la deformidad cosmética y la prevención de infecciones. PACIENTES Y MÉTODOS: se realizó un estudio retrospectivo y transversal en nuestro departamento entre abril de 2016 y mayo de 2017. Se incluyeron 16 pacientes que se sometieron a una craneotomía por traumatismo craneal y fractura deprimida. El diagnóstico se realizó mediante tomografía computarizada craneal simple con reconstrucción 3D. RESULTADOS: se incluyeron 16 pacientes, 5 casos femeninos (31,2%) y 11 masculinos (68,8%). En 12 casos se observó fractura expuesta. En 7 casos la fractura se localizó en el hueso parietal; 5 casos en el hueso frontal y 4 casos en hueso temporal. El puntaje promedio en la Escala de Coma de Glasgow fue 13. No hubo complicaciones o muertes. CONCLUSIONES: la remodelación y el reposicionamiento del injerto óseo autólogo permite un resultado cosmético adecuado evitando la colocación de implantes sin aumentar los costos y riesgos adicionales.
Assuntos
Traumatismos Craniocerebrais , Fraturas Ósseas , Fratura do Crânio com Afundamento , Masculino , Feminino , Humanos , Fratura do Crânio com Afundamento/cirurgia , Fratura do Crânio com Afundamento/diagnóstico , Estudos Retrospectivos , Craniotomia , Osso Frontal/cirurgia , Traumatismos Craniocerebrais/cirurgia , Instituições AcadêmicasRESUMO
Six new epigean freshwater species of the genus Caecidotea in Mexico are described. These species were collected in waterbodies located along the Trans-Mexican Volcanic Belt (TMVB) and the eastern slope of the country: Caecidotea buzwilsoni sp. nov., Caecidotea chicoensis sp. nov., Caecidotea alvarezi sp. nov., Caecidotea mintzita sp. nov., Caecidotea zacapuensis sp. nov., and one additional species Caecidotea villalobosi sp. nov. is described from the Papaloapan basin at the Atlantic Slope of Mexico. The taxonomic treatment for each species includes a detailed description, figures of characters of diagnostic importance and comments. We also provide an updated map of Caecidotea records in Mexico. This work substantially increases the number of epigean Caecidotea known to occur in Mexico to 11 species, a new total of 99 species described to North America.
Assuntos
Isópodes , Distribuição Animal , Animais , Água Doce , Isópodes/anatomia & histologia , Isópodes/classificação , México , Especificidade da EspécieRESUMO
Atazanavir (ATV) has already been considered as a potential repurposing drug to 2019 coronavirus disease (COVID-19); however, there are controversial reports on its mechanism of action and effectiveness as anti-severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Through the pre-clinical chain of experiments: enzymatic, molecular docking, cell-based and in vivo assays, it is demonstrated here that both SARS-CoV-2 B.1 lineage and variant of concern gamma are susceptible to this antiretroviral. Enzymatic assays and molecular docking calculations showed that SARS-CoV-2 main protease (Mpro) was inhibited by ATV, with Morrison's inhibitory constant (Ki) 1.5-fold higher than GC376 (a positive control) dependent of the catalytic water (H2Ocat) content. ATV was a competitive inhibitor, increasing the Mpro's Michaelis-Menten (Km) more than sixfold. Cell-based assays indicated that different lineages of SARS-CoV-2 is susceptible to ATV. Using oral administration of ATV in mice to reach plasmatic exposure similar to humans, transgenic mice expression in human angiotensin converting enzyme 2 (K18-hACE2) were partially protected against lethal challenge with SARS-CoV-2 gamma. Moreover, less cell death and inflammation were observed in the lung from infected and treated mice. Our studies may contribute to a better comprehension of the Mpro/ATV interaction, which could pave the way to the development of specific inhibitors of this viral protease.
RESUMO
BACKGROUND: In patients with severe traumatic brain injury (TBI), there is a lack of consensus about the need and time to perform a tracheostomy. Nowadays, the decision is individualized to each case. It is considered that patients that will need a tracheostomy profit by performing it earlier. PATIENTS AND METHODS: An observational and prospective study was performed. One hundred and twenty patients in a period of 18 months between 2016 and 2018, older than 18 years, with severe TBI at the first 24 h of trauma were analyzed. Clinical, biochemical, and radiological findings at admission were measured; patients were followed up until discharge. The statistical analysis was made with Student's t-test, χ2, and prevalence risk ratio. RESULTS: Ten associated factors were grouped according to the prevalence risk ratio. The principal factors were CRASH score, IMPACT score, SAPS II score, APACHE II score, age, revised trauma score, Glasgow Coma Scale, subdural hematoma, uni or bilateral abnormal pupil reactivity, and collapse of basal cisterns. CONCLUSIONS: We conclude that there are multiple factors associated with the need for tracheostomy in adult patients with severe TBI and it is possible to predict according to our findings from admission which patients will profit by this procedure.
ANTECEDENTES: No existe aún consenso respecto de la necesidad y el tiempo de realización de traqueostomía en el paciente con trauma craneoencefálico (TCE) grave. En la actualidad, la decisión se individualiza en cada caso. Se considera que los pacientes que requieren traqueostomía tendrán mayor beneficio si se realiza de forma temprana. MÉTODO: Se llevó a cabo un estudio observacional y prospectivo, en un periodo de 18 meses entre 2016 y 2018, con 120 pacientes mayores de 18 años con diagnóstico de TCE grave, en las primeras 24 horas del trauma. Se evaluaron datos clínicos, bioquímicos y radiológicos al ingreso, y se siguió hasta el alta hospitalaria. Se analizan las variables con las prueba t de Student y ji al cuadrado, y también la tasa de riesgo de prevalencia. RESULTADOS: Los factores de riesgo asociados con la necesidad de traqueostomía en el paciente con TCE grave fueron los resultados en las escalas CRASH, IMPACT, SAPS II y APACHE II, la edad, la puntuación de la Revised Trauma Score y de la Escala de Glasgow al ingreso, la presencia y el volumen de hematoma subdural, la respuesta pupilar anormal unilateral o bilateral, y el colapso parcial o total de las cisternas basales. CONCLUSIONES: Existen numerosos factores de riesgo asociados con la necesidad de traqueostomía en los pacientes adultos con TCE grave, y es posible predecir desde el momento del ingreso qué pacientes se beneficiarán de la realización de una traqueostomía.
Assuntos
Lesões Encefálicas Traumáticas , Escala de Gravidade do Ferimento , Traqueostomia , Adulto , Lesões Encefálicas Traumáticas/complicações , Lesões Encefálicas Traumáticas/terapia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Respiração Artificial , Fatores de Risco , Adulto JovemRESUMO
A new freshwater isopod, Caecidotea camaxtli sp. nov. (Isopoda, Asellidae) is described from Mexico. The new species can be distinguished from all other species of Caecidotea by the presence of cuticular scales on the caudal process, as well as a short and simple cannula in the apex of the endopodite of pleopod II. [Zoobank URL: urn:lsid:zoobank.org:act:082CF870-ABC3-4E25-B5F2-8CA59359C2B0].
Assuntos
Isópodes , Animais , Meio Ambiente , Água Doce , MéxicoRESUMO
Community marine reserves are geographical areas closed to fishing activities, implemented and enforced by the same fishermen that fish around them. Their main objective is to recover commercial stocks of fish and invertebrates. While marine reserves have proven successful in many parts of the world, their success near important marine predator colonies, such as the California sea lion (Zalophus californianus) and the Pacific harbor seal (Phoca vitulina richardii), is yet to be analyzed. In response to the concerns expressed by local fishermen about the impact of the presence of pinnipeds on their communities' marine reserves, we conducted underwater surveys around four islands in the Pacific west of the Baja California Peninsula: two without reserves (Todos Santos and San Roque); one with a recently established reserve (San Jeronimo); and, a fourth with reserves established eight years ago (Natividad). All these islands are subject to similar rates of exploitation by fishing cooperatives with exclusive rights. We estimated fish biomass and biodiversity in the seas around the islands, applying filters for potential California sea lion and harbor seal prey using known species from the literature. Generalized linear mixed models revealed that the age of the reserve has a significant positive effect on fish biomass, while the site (inside or outside of the reserve) did not, with a similar result found for the biomass of the prey of the California sea lion. Fish biodiversity was also higher around Natividad Island, while invertebrate biodiversity was higher around San Roque. These findings indicate that marine reserves increase overall fish diversity and biomass, despite the presence of top predators, even increasing the numbers of their potential prey. Community marine reserves may help to improve the resilience of marine mammals to climate-driven phenomena and maintain a healthy marine ecosystem for the benefit of both pinnipeds and fishermen.
Assuntos
Biomassa , Espécies em Perigo de Extinção , Phoca/fisiologia , Comportamento Predatório , Leões-Marinhos/fisiologia , Animais , Biodiversidade , Peixes/fisiologia , Cadeia AlimentarRESUMO
Eight molecules, four peptides (SPs) and four lipopeptides (LPs) derived by rational design from surfactin, a well-known secreted biosurfactant from Bacillus subtilis, were produced employing Fmoc-based solid-phase synthesis. These new peptides were tested to evaluate their potential biosurfactant and biological activities, aiming at possible applications in industrial, biological, pharmaceutical, and medical use. Five molecules (SP1, SP2, SP4, LP5, and LP8) presented potential for medical uses, mainly due to their drug delivery properties as suggested by their synergistic activity with the antibiotic vancomycin against Staphylococcus aureus. All synthetic peptides showed low toxicity against Vero cell cultures, in assays of hemolysis, and in different cytotoxicity assays. In addition, we found that three peptides (SP1, LP6, and LP7) had potential technological and industrial use because of their emulsifying capacity, low toxicity, and ability to physically stabilize solutions. These novel molecules retained some properties of the parental molecule (surfactin, which was originally obtained through nonribosomal synthesis in Bacillus subtilis) but have the advantage of being linear peptides, which can be produced at large scales through the use of conventional heterologous protein expression protocols.
Assuntos
Bacillus subtilis/metabolismo , Lipopeptídeos/síntese química , Peptídeos Cíclicos/química , Peptídeos/síntese química , Técnicas de Síntese em Fase Sólida/métodos , Animais , Bacillus subtilis/química , Proteínas de Bactérias/química , Chlorocebus aethiops , Portadores de Fármacos/síntese química , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Sinergismo Farmacológico , Emulsificantes/síntese química , Emulsificantes/química , Emulsificantes/farmacologia , Humanos , Lipopeptídeos/química , Lipopeptídeos/farmacologia , Peptídeos/química , Peptídeos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Vancomicina/farmacologia , Células VeroRESUMO
The cotranslational folding is recognized as a very cooperative process that occurs after the nearly completion of the polypeptide sequence of a domain. Here we investigated the challenges faced by polypeptide segments of a non-vectorial ß-barrel fold. Besides the biological interest behind the SARS coronavirus non-structural protein 1 (nsp1, 117 amino acids), this study model has two structural features that motivated its use in this work: 1- its recombinant production is dependent on the temperature, with greater solubility when expressed at low temperatures. This is an indication of the cotranslational guidance to the native protein conformation. 2- Conversely, nsp1 has a six-stranded, mixed parallel/antiparallel ß-barrel with intricate long-range interactions, indicating it will need the full-length protein to fold properly. We used non-denaturing purification conditions that allowed the characterization of polypeptide chains of different lengths, mimicking the landscape of the cotranslational fold of a ß-barrel, and avoiding the major technical hindrances of working with the nascent polypeptide bound to the ribosome. Our results showed partially folded states formed as soon as the amino acids of the second ß-strand were present (55 amino acids). These partially folded states are different based on the length of polypeptide chain. The native α-helix (amino acids 24-37) was identified as a transient structure (~20-30% propensity). We identified the presence of regular secondary structure after the fourth native ß-strand is present (89 amino acids), in parallel to the collapse to a non-native 3D structure. Interestingly the polypeptide sequences of the native strands ß2, ß3 and ß4 have characteristics of α-helices. Our comprehensive analyses support the idea that incomplete polypeptide chains, such as the ones of nascent proteins much earlier than the end of the translation, adopt an abundance of specific transient folds, instead of disordered conformations.