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1.
BMC Neurol ; 24(1): 271, 2024 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-39097695

RESUMEN

BACKGROUND: Among ambulatory people with incomplete spinal cord injury (iSCI), balance deficits are a primary factor limiting participation in walking activities. There is broad recognition that effective interventions are needed to enhance walking balance following iSCI. Interventions that amplify self-generated movements (e.g., error augmentation) can accelerate motor learning by intensifying sensorimotor feedback and facilitating exploration of motor control strategies. These features may be beneficial for retraining walking balance after iSCI. We have developed a cable-driven robot that creates a movement amplification environment during treadmill walking. The robot applies a continuous, laterally-directed, force to the pelvis that is proportional in magnitude to real-time lateral velocity. Our purpose is to investigate the effects of locomotor training in this movement amplification environment on walking balance. We hypothesize that for ambulatory people with iSCI, locomotor training in a movement amplification environment will be more effective for improving walking balance and participation in walking activities than locomotor training in a natural environment (no applied external forces). METHODS: We are conducting a two-arm parallel-assignment intervention. We will enroll 36 ambulatory participants with chronic iSCI. Participants will be randomized into either a control or experimental group. Each group will receive 20 locomotor training sessions. Training will be performed in either a traditional treadmill environment (control) or in a movement amplification environment (experimental). We will assess changes using measures that span the International Classification of Functioning, Disability and Health (ICF) framework including 1) clinical outcome measures of gait, balance, and quality of life, 2) biomechanical assessments of walking balance, and 3) participation in walking activities quantified by number of steps taken per day. DISCUSSION: Training walking balance in people with iSCI by amplifying the individual's own movement during walking is a radical departure from current practice and may result in new strategies for addressing balance impairments. Knowledge gained from this study will expand our understanding of how people with iSCI improve walking balance and how an intervention targeting walking balance affects participation in walking activities. Successful outcomes could motivate development of clinically feasible tools to replicate the movement amplification environment within clinical settings. TRIAL REGISTRATION: NCT04340063.


Asunto(s)
Marcha , Traumatismos de la Médula Espinal , Traumatismos de la Médula Espinal/rehabilitación , Traumatismos de la Médula Espinal/fisiopatología , Humanos , Marcha/fisiología , Adulto , Terapia por Ejercicio/métodos , Equilibrio Postural/fisiología , Caminata/fisiología , Masculino , Femenino , Robótica/métodos , Método Simple Ciego , Persona de Mediana Edad , Locomoción/fisiología
2.
Bioorg Med Chem Lett ; 32: 127661, 2021 01 15.
Artículo en Inglés | MEDLINE | ID: mdl-33160023

RESUMEN

We previously reported medicinal chemistry efforts that identified MK-5204, an orally efficacious ß-1,3-glucan synthesis inhibitor derived from the natural product enfumafungin. Further extensive optimization of the C2 triazole substituent identified 4-pyridyl as the preferred replacement for the carboxamide of MK-5204, leading to improvements in antifungal activity in the presence of serum, and increased oral exposure. Reoptimizing the aminoether at C3 in the presence of this newly discovered C2 substituent, confirmed that the (R) t-butyl, methyl aminoether of MK-5204 provided the best balance of these two key parameters, culminating in the discovery of ibrexafungerp, which is currently in phase III clinical trials. Ibrexafungerp displayed significantly improved oral efficacy in murine infection models, making it a superior candidate for clinical development as an oral treatment for Candida and Aspergillus infections.


Asunto(s)
Antifúngicos/farmacología , Aspergillus/efectos de los fármacos , Candida albicans/efectos de los fármacos , Glicósidos/química , Triterpenos/química , beta-Glucanos/metabolismo , Administración Oral , Animales , Antifúngicos/síntesis química , Antifúngicos/farmacocinética , Antifúngicos/uso terapéutico , Aspergilosis/tratamiento farmacológico , Candidiasis/tratamiento farmacológico , Modelos Animales de Enfermedad , Glicósidos/farmacocinética , Glicósidos/farmacología , Glicósidos/uso terapéutico , Semivida , Ratones , Relación Estructura-Actividad , Triterpenos/farmacocinética , Triterpenos/farmacología , Triterpenos/uso terapéutico
3.
J Biol Chem ; 294(47): 17848-17862, 2019 11 22.
Artículo en Inglés | MEDLINE | ID: mdl-31624149

RESUMEN

Ricin undergoes retrograde transport to the endoplasmic reticulum (ER), and ricin toxin A chain (RTA) enters the cytosol from the ER. Previous reports indicated that RTA inhibits activation of the unfolded protein response (UPR) in yeast and in mammalian cells. Both precursor (preRTA) and mature form of RTA (mRTA) inhibited splicing of HAC1u (u for uninduced) mRNA, suggesting that UPR inhibition occurred on the cytosolic face of the ER. Here, we examined the role of ribosome binding and depurination activity on inhibition of the UPR using mRTA mutants. An active-site mutant with very low depurination activity, which bound ribosomes as WT RTA, did not inhibit HAC1u mRNA splicing. A ribosome-binding mutant, which showed reduced binding to ribosomes but retained depurination activity, inhibited HAC1u mRNA splicing. This mutant allowed separation of the UPR inhibition by RTA from cytotoxicity because it reduced the rate of depurination. The ribosome-binding mutant inhibited the UPR without affecting IRE1 oligomerization or cleavage of HAC1u mRNA at the splice site junctions. Inhibition of the UPR correlated with the depurination level, suggesting that ribosomes play a role in splicing of HAC1u mRNA. We show that HAC1u mRNA is associated with ribosomes and does not get processed on depurinated ribosomes, thereby inhibiting the UPR. These results demonstrate that RTA inhibits HAC1u mRNA splicing through its depurination activity on the ribosome without directly affecting IRE1 oligomerization or the splicing reaction and provide evidence that IRE1 recognizes HAC1u mRNA that is associated with ribosomes.


Asunto(s)
Factores de Transcripción con Cremalleras de Leucina de Carácter Básico/metabolismo , Estrés del Retículo Endoplásmico/efectos de los fármacos , Purinas/metabolismo , Empalme del ARN/genética , Proteínas Represoras/metabolismo , Ribosomas/metabolismo , Ricina/toxicidad , Proteínas de Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/metabolismo , Estrés del Retículo Endoplásmico/genética , Regulación Fúngica de la Expresión Génica/efectos de los fármacos , Glicoproteínas de Membrana/metabolismo , Modelos Biológicos , Mutación/genética , Multimerización de Proteína/efectos de los fármacos , Proteínas Serina-Treonina Quinasas/metabolismo , Procesamiento Postranscripcional del ARN/efectos de los fármacos , Procesamiento Postranscripcional del ARN/genética , Empalme del ARN/efectos de los fármacos , ARN Mensajero/metabolismo , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/genética , Respuesta de Proteína Desplegada/efectos de los fármacos , Respuesta de Proteína Desplegada/genética
4.
Bioorg Med Chem Lett ; 30(17): 127357, 2020 09 01.
Artículo en Inglés | MEDLINE | ID: mdl-32738971

RESUMEN

Our previously reported efforts to produce an orally active ß-1,3-glucan synthesis inhibitor through the semi-synthetic modification of enfumafungin focused on replacing the C2 acetoxy moiety with an aminotetrazole and the C3 glycoside with a N,N-dimethylaminoether moiety. This work details further optimization of the C2 heterocyclic substituent, which identified 3-carboxamide-1,2,4-triazole as a replacement for the aminotetrazole with comparable antifungal activity. Alkylation of either the carboxamidetriazole at C2 or the aminoether at C3 failed to significantly improve oral efficacy. However, replacement of the isopropyl alpha amino substituent with a t-butyl, improved oral exposure while maintaining antifungal activity. These two structural modifications produced MK-5204, which demonstrated broad spectrum activity against Candida species and robust oral efficacy in a murine model of disseminated Candidiasis without the N-dealkylation liability observed for the previous lead.


Asunto(s)
Antifúngicos/química , Triazoles/química , beta-Glucanos/metabolismo , Administración Oral , Animales , Antifúngicos/metabolismo , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Candida/efectos de los fármacos , Candidiasis/tratamiento farmacológico , Modelos Animales de Enfermedad , Glucosiltransferasas/antagonistas & inhibidores , Glucosiltransferasas/metabolismo , Glicósidos/química , Semivida , Ratones , Pruebas de Sensibilidad Microbiana , Estereoisomerismo , Relación Estructura-Actividad , Triazoles/metabolismo , Triazoles/farmacología , Triazoles/uso terapéutico , Triterpenos/química , beta-Glucanos/química
5.
Infect Immun ; 84(12): 3290-3301, 2016 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-27600507

RESUMEN

The A1 subunits of Shiga toxin 1 (Stx1A1) and Shiga toxin 2 (Stx2A1) interact with the conserved C termini of ribosomal-stalk P-proteins to remove a specific adenine from the sarcin/ricin loop. We previously showed that Stx2A1 has higher affinity for the ribosome and higher catalytic activity than Stx1A1. To determine if conserved arginines at the distal face of the active site contribute to the higher affinity of Stx2A1 for the ribosome, we mutated Arg172, Arg176, and Arg179 in both toxins. We show that Arg172 and Arg176 are more important than Arg179 for the depurination activity and toxicity of Stx1A1 and Stx2A1. Mutation of a single arginine reduced the depurination activity of Stx1A1 more than that of Stx2A1. In contrast, mutation of at least two arginines was necessary to reduce depurination by Stx2A1 to a level similar to that of Stx1A1. R176A and R172A/R176A mutations eliminated interaction of Stx1A1 and Stx2A1 with ribosomes and with the stalk, while mutation of Arg170 at the active site reduced the binding affinity of Stx1A1 and Stx2A1 for the ribosome, but not for the stalk. These results demonstrate that conserved arginines at the distal face of the active site are critical for interactions of Stx1A1 and Stx2A1 with the stalk, while a conserved arginine at the active site is critical for non-stalk-specific interactions with the ribosome. Arginine mutations at either site reduced ribosome interactions of Stx1A1 and Stx2A1 similarly, indicating that conserved arginines are critical for ribosome interactions but do not contribute to the higher affinity of Stx2A1 for the ribosome.


Asunto(s)
Secuencia Conservada , Proteínas de Escherichia coli/metabolismo , Complejos Multienzimáticos/metabolismo , Prefenato Deshidratasa/metabolismo , Ribosomas/metabolismo , Saccharomyces/metabolismo , Toxinas Shiga/metabolismo , Animales , Sitios de Unión , Proteínas de Escherichia coli/genética , Regulación Bacteriana de la Expresión Génica/fisiología , Modelos Moleculares , Complejos Multienzimáticos/genética , Mutación , Plásmidos , Prefenato Deshidratasa/genética , Unión Proteica , Conformación Proteica , Subunidades de Proteína , ARN de Hongos/metabolismo , Ratas , Ribosomas/química , Saccharomyces/genética , Toxinas Shiga/química
6.
Infect Immun ; 84(1): 149-61, 2016 01.
Artículo en Inglés | MEDLINE | ID: mdl-26483409

RESUMEN

Shiga toxin (Stx)-producing Escherichia coli (STEC) infections can lead to life-threatening complications, including hemorrhagic colitis (HC) and hemolytic-uremic syndrome (HUS), which is the most common cause of acute renal failure in children in the United States. Stx1 and Stx2 are AB5 toxins consisting of an enzymatically active A subunit associated with a pentamer of receptor binding B subunits. Epidemiological evidence suggests that Stx2-producing E. coli strains are more frequently associated with HUS than Stx1-producing strains. Several studies suggest that the B subunit plays a role in mediating toxicity. However, the role of the A subunits in the increased potency of Stx2 has not been fully investigated. Here, using purified A1 subunits, we show that Stx2A1 has a higher affinity for yeast and mammalian ribosomes than Stx1A1. Biacore analysis indicated that Stx2A1 has faster association and dissociation with ribosomes than Stx1A1. Analysis of ribosome depurination kinetics demonstrated that Stx2A1 depurinates yeast and mammalian ribosomes and an RNA stem-loop mimic of the sarcin/ricin loop (SRL) at a higher catalytic rate and is a more efficient enzyme than Stx1A1. Stx2A1 depurinated ribosomes at a higher level in vivo and was more cytotoxic than Stx1A1 in Saccharomyces cerevisiae. Stx2A1 depurinated ribosomes and inhibited translation at a significantly higher level than Stx1A1 in human cells. These results provide the first direct evidence that the higher affinity for ribosomes in combination with higher catalytic activity toward the SRL allows Stx2A1 to depurinate ribosomes, inhibit translation, and exhibit cytotoxicity at a significantly higher level than Stx1A1.


Asunto(s)
Ribosomas/metabolismo , Toxina Shiga I/metabolismo , Toxina Shiga II/metabolismo , Toxina Shiga/metabolismo , Escherichia coli Shiga-Toxigénica/metabolismo , Animales , Línea Celular , Infecciones por Escherichia coli/microbiología , Células HEK293 , Síndrome Hemolítico-Urémico/microbiología , Humanos , Unión Proteica , Biosíntesis de Proteínas/genética , Ratas , Saccharomyces cerevisiae/genética
7.
Bioorg Med Chem Lett ; 25(24): 5813-8, 2015 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-26542966

RESUMEN

The clinical success of the echinocandins, which can only be administered parentally, has validated ß-1,3-glucan synthase (GS) as an antifungal target. Semi-synthetic modification of enfumafungin, a triterpene glycoside natural product, was performed with the aim of producing a new class of orally active GS inhibitors. Replacement of the C2 acetoxy moiety with various heterocycles did not improve GS or antifungal potency. However, replacement of the C3 glycoside with an aminoether moiety dramatically improved oral pharmacokinetic (PK) properties while maintaining GS and antifungal potency. Installing an aminotetrazole at C2 in conjunction with an N-alkylated aminoether at C3 produced derivatives with significantly improved GS and antifungal potency that exhibited robust oral efficacy in a murine model of disseminated candidiasis.


Asunto(s)
Antifúngicos/química , Glicósidos/química , Triterpenos/química , beta-Glucanos/química , Administración Oral , Animales , Antifúngicos/farmacocinética , Antifúngicos/uso terapéutico , Aspergillus fumigatus/efectos de los fármacos , Candida albicans/efectos de los fármacos , Candidiasis/tratamiento farmacológico , Candidiasis/veterinaria , Glucosiltransferasas/antagonistas & inhibidores , Glucosiltransferasas/metabolismo , Semivida , Ratones , Pruebas de Sensibilidad Microbiana , Relación Estructura-Actividad , Terpenos/química , beta-Glucanos/farmacocinética , beta-Glucanos/uso terapéutico
8.
Compr Psychiatry ; 57: 106-11, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-25434845

RESUMEN

BACKGROUND AND OBJECTIVES: Emotion plays a significant role in schizophrenia. Emotional awareness (i.e., attention to and clarity of emotions) is associated with a wide range of outcomes. Given that individuals with schizophrenia and schizoaffective disorder differ in the significance of their mood symptoms, the present research examined whether the association between emotional awareness and delusions differs for these two groups of patients. METHODS: Emotional awareness (i.e., attention to and clarity of emotions) was measured with self-report in a sample of 44 individuals diagnosed with either schizophrenia or schizoaffective disorder. Clinical ratings of delusions were made using the Scale for the Assessment of Positive Symptoms. RESULTS: For the sample as a whole, individuals with higher levels of attention to emotion tended to have more severe delusions. In addition, diagnostic group significantly moderated the relation between emotional clarity and delusions. LIMITATIONS: Conclusions regarding causality cannot be drawn due to the cross-sectional design. Replication is particularly important given the small sample sizes. CONCLUSIONS: The present research indicates that emotional awareness is associated with delusions. The results raise the possibility that the emotional factors that contribute to delusional beliefs among individuals with schizophrenia differ in at least some ways from the emotional factors that contribute to delusional beliefs among individuals with schizoaffective disorder.


Asunto(s)
Concienciación , Deluciones/psicología , Emociones , Trastornos Psicóticos/psicología , Psicología del Esquizofrénico , Adulto , Estudios Transversales , Manual Diagnóstico y Estadístico de los Trastornos Mentales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Trastornos del Humor/complicaciones , Trastornos del Humor/psicología , Escalas de Valoración Psiquiátrica , Adulto Joven
9.
Proc Natl Acad Sci U S A ; 109(4): 1056-61, 2012 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-22203984

RESUMEN

Ethnohistoric accounts of late precontact Hawaiian archaic states emphasize the independence of chiefly controlled territories (ahupua'a) based on an agricultural, staple economy. However, elite control of unevenly distributed resources, such as high-quality volcanic rock for adze production, may have provided an alternative source of economic power. To test this hypothesis we used nondestructive energy-dispersive X-ray fluorescence (ED-XRF) analysis of 328 lithic artifacts from 36 archaeological features in the Kahikinui district, Maui Island, to geochemically characterize the source groups. This process was followed by a limited sampling using destructive wavelength-dispersive X-ray fluorescence (WD-XRF) analysis to more precisely characterize certain nonlocal source groups. Seventeen geochemical groups were defined, eight of which represent extra-Maui Island sources. Although the majority of stone tools were derived from Maui Island sources (71%), a significant quantity (27%) of tools derived from extraisland sources, including the large Mauna Kea quarry on Hawai'i Island as well as quarries on O'ahu, Moloka'i, and Lana'i islands. Importantly, tools quarried from extralocal sources are found in the highest frequency in elite residential features and in ritual contexts. These results suggest a significant role for a wealth economy based on the control and distribution of nonagricultural goods and resources during the rise of the Hawaiian archaic states.


Asunto(s)
Arqueología/métodos , Comercio/historia , Etnicidad/historia , Artículos Domésticos/historia , Hawaii , Historia del Siglo XVII , Historia del Siglo XVIII , Humanos , Análisis de Componente Principal , Silicatos/química , Espectrometría por Rayos X
10.
J Biol Chem ; 288(42): 30270-30284, 2013 Oct 18.
Artículo en Inglés | MEDLINE | ID: mdl-24003229

RESUMEN

Ricin inhibits protein synthesis by depurinating the α-sarcin/ricin loop (SRL). Ricin holotoxin does not inhibit translation unless the disulfide bond between the A (RTA) and B (RTB) subunits is reduced. Ricin holotoxin did not bind ribosomes or depurinate them but could depurinate free RNA. When RTA is separated from RTB, arginine residues located at the interface are exposed to the solvent. Because this positively charged region, but not the active site, is blocked by RTB, we mutated arginine residues at or near the interface of RTB to determine if they are critical for ribosome binding. These variants were structurally similar to wild type RTA but could not bind ribosomes. Their K(m) values and catalytic rates (k(cat)) for an SRL mimic RNA were similar to those of wild type, indicating that their activity was not altered. However, they showed an up to 5-fold increase in K(m) and up to 38-fold decrease in kcat toward ribosomes. These results suggest that the stalk binding stimulates the catalysis of ribosome depurination by RTA. The mutated arginines have side chains behind the active site cleft, indicating that the ribosome binding surface of RTA is on the opposite side of the surface that interacts with the SRL. We propose that stalk binding stimulates the catalysis of ribosome depurination by orienting the active site of RTA toward the SRL and thereby allows docking of the target adenine into the active site. This model may apply to the translation factors that interact with the stalk.


Asunto(s)
Adenina/química , Arginina/química , Ribosomas/química , Ricina/química , Saccharomyces cerevisiae/química , Arginina/genética , Catálisis , Dominio Catalítico , Unión Proteica , Ribosomas/genética , Ricina/genética
11.
Am J Physiol Endocrinol Metab ; 305(10): E1230-40, 2013 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-24002572

RESUMEN

Inorganic materials have properties that can be advantageous in bioencapsulation for cell transplantation. Our aim was to engineer a hybrid inorganic/soft tissue construct by inducing pancreatic islets to grow an inorganic shell. We created pancreatic islets surrounded by porous silica, which has potential application in the immunoprotection of islets in transplantation therapies for type 1 diabetes. The new method takes advantage of the islet capsule surface as a template for silica formation. Mouse and human islets were exposed to medium containing saturating silicic acid levels for 9-15 min. The resulting tissue constructs were then cultured for up to 4 wk under normal conditions. Scanning electron microscopy and energy dispersive X-ray spectroscopy was used to monitor the morphology and elemental composition of the material at the islet surface. A cytokine assay was used to assess biocompatibility with macrophages. Islet survival and function were assessed by confocal microscopy, glucose-stimulated insulin release assays, oxygen flux at the islet surface, expression of key genes by RT-PCR, and syngeneic transplant into diabetic mice.


Asunto(s)
Composición de Medicamentos/métodos , Islotes Pancreáticos/citología , Islotes Pancreáticos/fisiología , Dióxido de Silicio/química , Animales , Técnicas de Cultivo de Célula , Supervivencia Celular/fisiología , Materiales Biocompatibles Revestidos/química , Diabetes Mellitus Tipo 1/terapia , Humanos , Trasplante de Islotes Pancreáticos/métodos , Ratones , Oxígeno/metabolismo , Transición de Fase , Ingeniería de Tejidos/métodos
12.
RNA ; 17(1): 201-10, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21098653

RESUMEN

Ricin produced by the castor bean plant and Shiga toxins produced by pathogenic Escherichia coli (STEC) and Shigella dysenteriae are type II ribosome inactivating proteins (RIPs), containing an enzymatically active A subunit that inhibits protein synthesis by removing an adenine from the α-sarcin/ricin loop (SRL) of the 28S rRNA. There are currently no known antidotes to Shiga toxin or ricin, and the ability to screen large chemical libraries for inhibitors has been hindered by lack of quantitative assays for catalytic activity that can be adapted to a high throughput format. Here, we describe the development of a robust and quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay that can directly measure the toxins' catalytic activity on ribosomes and can be used to examine the kinetics of depurination in vivo. The qRT-PCR assay exhibited a much wider dynamic range than the previously used primer extension assay (500-fold vs. 16-fold) and increased sensitivity (60 pM vs. 0.57 nM). Using this assay, a 400-fold increase in ribosome depurination was observed in yeast expressing ricin A chain (RTA) relative to uninduced cells. Pteroic acid, a known inhibitor of enzymatic activity, inhibited ribosome depurination by RTA and Shiga toxin 2 with an IC(50) of ∼ 100 µM, while inhibitors of ricin transport failed to inhibit catalytic activity. These results demonstrate that the qRT-PCR assay would enable refined kinetic studies with RIPs and could be a powerful screening tool to identify inhibitors of catalytic activity.


Asunto(s)
Modelos Biológicos , Purinas/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Proteínas Inactivadoras de Ribosomas/metabolismo , Ribosomas/metabolismo , Ricina/análisis , Saccharomyces cerevisiae/metabolismo , Toxina Shiga/análisis , Bioensayo , Sustancias para la Guerra Química/análisis , Pterinas/farmacología , ARN de Hongos/genética , ARN de Hongos/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ricina/genética , Saccharomyces cerevisiae/efectos de los fármacos , Saccharomyces cerevisiae/genética , Toxina Shiga/genética
13.
Bioorg Med Chem Lett ; 23(11): 3253-6, 2013 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-23623416

RESUMEN

Echinocandins and pneumocandins are classes of lipocyclohexapeptides that are broad spectrum antifungal agents. They inhibit fungal specific 1,3-ß-glucan synthase activity which is an essential component of the fungal cell wall. Chemical modifications of these two leads have produced three clinical agents namely caspofungin, micafungin and anidulafungin. The presence of hydroxy-glutamine versus threonine and unsaturated linear fatty acid versus branched chain saturated fatty acid differentiate the two classes of compounds with profound differences in their hemolytic properties. In the current study, we have replaced the side chain of the cyclohexapeptides with a common aromatic heterocyclic acyl side chain and compared the biological activities of the cores head-to-head and for the first time demonstrated the role played by the acyl chain and the hydroxy-glutamine for the antifungal potency.


Asunto(s)
Antifúngicos/síntesis química , Equinocandinas/química , Isoxazoles/química , Animales , Antifúngicos/farmacología , Antifúngicos/uso terapéutico , Candida/efectos de los fármacos , Candida/enzimología , Candidiasis/tratamiento farmacológico , Caspofungina , Pared Celular/efectos de los fármacos , Equinocandinas/farmacología , Equinocandinas/uso terapéutico , Glucosiltransferasas/antagonistas & inhibidores , Glucosiltransferasas/metabolismo , Glutamina/química , Lipopéptidos , Ratones , Pruebas de Sensibilidad Microbiana , Unión Proteica , Relación Estructura-Actividad , Treonina/química
14.
J Nat Prod ; 76(3): 334-45, 2013 Mar 22.
Artículo en Inglés | MEDLINE | ID: mdl-23259972

RESUMEN

Phaeofungin (1), a new cyclic depsipeptide isolated from Phaeosphaeria sp., was discovered by application of reverse genetics technology, using the Candida albicans fitness test (CaFT). Phaeofungin is comprised of seven amino acids and a ß,γ-dihydroxy-γ-methylhexadecanoic acid arranged in a 25-membered cyclic depsipeptide. Five of the amino acids were assigned with d-configurations. The structure was elucidated by 2D-NMR and HRMS-MS analysis of the natural product and its hydrolyzed linear peptide. The absolute configuration of the amino acids was determined by Marfey's method by complete and partial hydrolysis of 1. The CaFT profile of the phaeofungin-containing extract overlapped with that of phomafungin (3), another structurally different cyclic lipodepsipeptide isolated from a Phoma sp. using the same approach. Comparative biological characterization further demonstrated that these two fungal lipodepsipeptides are functionally distinct. While phomafungin was potentiated by cyclosporin A (an inhibitor of the calcineurin pathway), phaeofungin was synergized with aureobasidin A (2) (an inhibitor of the sphingolipid biosynthesis) and to some extent caspofungin (an inhibitor of glucan synthase). Furthermore, phaeofungin caused ATP release in wild-type C. albicans strains but phomafungin did not. It showed modest antifungal activity against C. albicans (MIC 16-32 µg/mL) and better activity against Aspergillus fumigatus (MIC 8-16 µg/mL) and Trichophyton mentagrophytes (MIC 4 µg/mL). The linear peptide was inactive, suggesting that the macrocyclic depsipeptide ring is essential for target engagement and antifungal activity.


Asunto(s)
Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Ascomicetos/química , Candida albicans/efectos de los fármacos , Depsipéptidos/aislamiento & purificación , Depsipéptidos/farmacología , Lipopéptidos/aislamiento & purificación , Lipopéptidos/farmacología , Antifúngicos/química , Candida albicans/genética , Caspofungina , Crassulaceae/microbiología , Depsipéptidos/química , Equinocandinas/química , Genoma , Lipopéptidos/química , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Resonancia Magnética Nuclear Biomolecular , Hojas de la Planta/microbiología , Tallos de la Planta/microbiología
15.
Proc Natl Acad Sci U S A ; 107(30): 13234-9, 2010 Jul 27.
Artículo en Inglés | MEDLINE | ID: mdl-20616079

RESUMEN

In Polynesia, the complex Society Islands chiefdoms constructed elaborate temples (marae), some of which reached monumental proportions and were associated with human sacrifice in the 'Oro cult. We investigated the development of temples on Mo'orea Island by 230Th/U dating of corals used as architectural elements (facing veneers, cut-and-dressed blocks, and offerings). The three largest coastal marae (associated with the highest-ranked chiefly lineages) and 19 marae in the inland 'Opunohu Valley containing coral architectural elements were dated. Fifteen corals from the coastal temples meet geochemical criteria for accurate 230Th/U dating, yield reproducible ages for each marae, and have a mean uncertainty of 9 y (2sigma). Of 41 corals from wetter inland sites, 12 show some diagenesis and may yield unreliable ages; however, the majority (32) of inland dates are considered accurate. We also obtained six 14C dates on charcoal from four marae. The dates indicate that temple architecture on Mo'orea Island developed rapidly over a period of approximately 140 y (ca. AD 1620-1760), with the largest coastal temples constructed immediately before initial European contact (AD 1767). The result of a seriation of architectural features corresponds closely with this chronology. Acropora coral veneers were superceded by cut-and-dressed Porites coral blocks on altar platforms, followed by development of multitier stepped altar platforms and use of pecked basalt stones associated with the late 'Oro cult. This example demonstrates that elaboration of ritual architecture in complex societies may be surprisingly rapid.


Asunto(s)
Antozoos/metabolismo , Arquitectura/métodos , Evolución Biológica , Conducta Ceremonial , Animales , Antozoos/anatomía & histología , Arquitectura/tendencias , Humanos , Polinesia , Contaminantes Radiactivos/análisis , Contaminantes Radiactivos/metabolismo , Torio/análisis , Torio/metabolismo , Factores de Tiempo , Uranio/análisis , Uranio/metabolismo
16.
Prev Chronic Dis ; 10: E43, 2013.
Artículo en Inglés | MEDLINE | ID: mdl-23537517

RESUMEN

INTRODUCTION: The Indo-Guyanese population is the largest immigrant minority population in Schenectady, New York. A clinic-based study in Schenectady and surveillance reports from Guyana found high diabetes prevalence and mortality among Guyanese of Indian descent. No community-based study has focused on diabetes among Indo-Guyanese immigrants in the United States. We sought information on the prevalence of diabetes and its complications in Indo-Guyanese adults in Schenectady and compared it with the prevalence among non-Hispanic white adults in Schenectady. METHODS: We administered a cross-sectional health survey at community venues in Schenectady in 2011. We identified diagnosed diabetes and its complications through self-reports by using a reliability-tested questionnaire. The final data set included 313 Indo-Guyanese and 327 non-Hispanic white adults aged 18 years or older. We compared the prevalence of diagnosed diabetes and diabetes complications between Indo-Guyanese and non-Hispanic whites. RESULTS: Most Indo-Guyanese participants were born in Guyana, whereas most non-Hispanic whites were born in the United States. The crude prevalence of diagnosed diabetes among Indo-Guyanese participants and non-Hispanic whites was 30.3% and 16.1%, respectively. The age-standardized prevalence was 28.7% among Indo-Guyanese participants, significantly higher than that among non-Hispanic whites (14.5%, P < .001). Indo-Guyanese participants who had diabetes had a lower body mass index and were more likely to report poor or fair general health and eye or vision complications than non-Hispanic whites who had diabetes. CONCLUSION: Our study confirms the higher prevalence of diabetes in Indo-Guyanese adults in Schenectady. The higher prevalence of complications suggests poor control of diabetes. Excess burden of diabetes in this population calls for further research and public health action.


Asunto(s)
Diabetes Mellitus/epidemiología , Indicadores de Salud , Adulto , Estudios Transversales , Complicaciones de la Diabetes/etnología , Diabetes Mellitus/diagnóstico , Diabetes Mellitus/etnología , Emigrantes e Inmigrantes/estadística & datos numéricos , Femenino , Guyana/etnología , Humanos , India/etnología , Masculino , Persona de Mediana Edad , Mortalidad/etnología , New York/epidemiología , Prevalencia
17.
ZDM ; 55(1): 109-118, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-36532825

RESUMEN

The mathematical medium of data visualization and other data representations (DV) has served as a primary means of communicating about the COVID-19 crisis. DVs about the pandemic are highly visible across news journalism and include an increasingly innovative and diverse set of representational forms. These representational forms employ multimodal, interactive, and narrative elements, among others, that create new possibilities for data storytelling. Building on current efforts to expand the teaching and learning of data practices in K-12 mathematics education, we argue that innovative DVs create new opportunities for teaching and learning mathematics, particularly during times of crisis. We illustrate our argument using three examples of innovative DVs from news journalism. We discuss how these DVs could serve as complementary resources alongside conventional graphs to support students as they use mathematics and mathematical representations to make sense of crises such as the COVID-19 pandemic. Our commentary seeks to bring current trends in data representation to bear in mathematics education. Leveraging such trends offers artifacts useful for teaching and opens up space for elevating emotion and experience as important aspects of mathematics curricula.

18.
Bioorg Med Chem Lett ; 22(22): 6811-6, 2012 Nov 15.
Artículo en Inglés | MEDLINE | ID: mdl-22672801

RESUMEN

Orally bioavailable inhibitors of ß-(1,3)-D-glucan synthase have been pursued as new, broad-spectrum fungicidal therapies suitable for treatment in immunocompromised patients. Toward this end, a collaborative medicinal chemistry program was established based on semisynthetic derivatization of the triterpenoid glycoside natural product enfumafungin in order to optimize in vivo antifungal activity and oral absorption properties. In the course of these studies, it was hypothesized that the pharmacokinetic properties of the semisynthetic enfumafungin analog 3 could be improved by tethering the alkyl groups proximal to the basic nitrogen of the C3-aminoether side chain into an azacyclic system, so as to preclude oxidative N-demethylation. The results of this research effort are disclosed herein.


Asunto(s)
Antifúngicos/síntesis química , Inhibidores Enzimáticos/síntesis química , Glucosiltransferasas/antagonistas & inhibidores , Glicósidos/química , Triterpenos/química , Administración Oral , Animales , Antifúngicos/química , Antifúngicos/farmacocinética , Candida albicans/efectos de los fármacos , Inhibidores Enzimáticos/química , Inhibidores Enzimáticos/farmacocinética , Glucosiltransferasas/metabolismo , Glicósidos/síntesis química , Glicósidos/farmacocinética , Semivida , Ratones , Relación Estructura-Actividad , Triterpenos/síntesis química , Triterpenos/farmacocinética
19.
J Neurophysiol ; 106(5): 2546-56, 2011 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-21832028

RESUMEN

This study investigated the potential influence of proximal sensory feedback on voluntary distal motor activity in the paretic upper limb of hemiparetic stroke survivors and the potential effect of voluntary distal motor activity on proximal muscle activity. Ten stroke subjects and 10 neurologically intact control subjects performed maximum voluntary isometric flexion and extension, respectively, at the metacarpophalangeal (MCP) joints of the fingers in two static arm postures and under three conditions of electrical stimulation of the arm. The tasks were quantified in terms of maximum MCP torque [MCP flexion (MCP(flex)) or MCP extension (MCP(ext))] and activity of targeted (flexor digitorum superficialis or extensor digitorum communis) and nontargeted upper limb muscles. From a previous study on the MCP stretch reflex poststroke, we expected stroke subjects to exhibit a modulation of voluntary MCP torque production by arm posture and electrical stimulation and increased nontargeted muscle activity. Posture 1 (flexed elbow, neutral shoulder) led to greater MCP(flex) in stroke subjects than posture 2 (extended elbow, flexed shoulder). Electrical stimulation did not influence MCP(flex) or MCP(ext) in either subject group. In stroke subjects, posture 1 led to greater nontargeted upper limb flexor activity during MCP(flex) and to greater elbow flexor and extensor activity during MCP(ext). Stroke subjects exhibited greater elbow flexor activity during MCP(flex) and greater elbow flexor and extensor activity during MCP(ext) than control subjects. The results suggest that static arm posture can modulate voluntary distal motor activity and accompanying muscle activity in the paretic upper limb poststroke.


Asunto(s)
Retroalimentación Sensorial/fisiología , Contracción Isométrica/fisiología , Actividad Motora/fisiología , Paresia/fisiopatología , Postura/fisiología , Accidente Cerebrovascular/fisiopatología , Anciano , Brazo/inervación , Brazo/fisiología , Estimulación Eléctrica , Femenino , Dedos/inervación , Dedos/fisiología , Humanos , Masculino , Articulación Metacarpofalángica/inervación , Articulación Metacarpofalángica/fisiología , Persona de Mediana Edad , Músculo Esquelético/fisiología , Torque , Volición/fisiología
20.
J Nat Prod ; 74(8): 1721-30, 2011 Aug 26.
Artículo en Inglés | MEDLINE | ID: mdl-21761939

RESUMEN

In a whole-cell mechanism of action (MOA)-based screening strategy for discovery of antifungal agents, Candida albicans was used, followed by testing of active extracts in the C. albicans fitness test (CaFT), which provides insight into the mechanism of action. A fermentation extract of an undescribed species of Metulocladosporiella that inhibited proteasome activity in a C. albicans fitness test was identified. The chemical genomic profile of the extract contained hypersensitivity of heterozygous deletion strains (strains that had one of the genes of the diploid genes knocked down) of genes represented by multiple subunits of the 25S proteasome. Two structurally related peptide aldehydes, named fellutamides C and D, were isolated from the extract. Fellutamides were active against C. albicans and Aspergillus fumigatus with MICs ranging from 4 to 16 µg/mL and against fungal proteasome (IC50 0.2 µg/mL). Both compounds showed proteasome activity against human tumor cell lines, potently inhibiting the growth of PC-3 prostate carcinoma cells, but not A549 lung carcinoma cells. In PC-3 cells compound treatment produced a G2M cell cycle block and induced apoptosis. Preliminary SAR studies indicated that the aldehyde group is critical for the antifungal activity and that the two hydroxy groups are quantitatively important for potency.


Asunto(s)
Antifúngicos , Ascomicetos/química , Candida albicans/efectos de los fármacos , Antifúngicos/química , Antifúngicos/aislamiento & purificación , Antifúngicos/farmacología , Fase G2/efectos de los fármacos , Humanos , Masculino , Estructura Molecular , Oligopéptidos/química , Oligopéptidos/aislamiento & purificación , Oligopéptidos/farmacología , Relación Estructura-Actividad
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