Goldilocks Energy Minimum: Peptide-Based Reversible Aggregation and Biosensing.

Colorimetric biosensors based on gold nanoparticle (AuNP) aggregation are often challenged by matrix interference in biofluids, poor specificity, and limited utility with clinical samples. Here, we propose a peptide-driven nanoscale disassembly approach, where AuNP aggregates induced by electrostatic attractions are dissociated in response to proteolytic cleavage. Initially, citrate-coated AuNPs were assembled via a short cationic peptide (RRK) and characterized by experiments and simulations. The dissociation peptides were then used to reversibly dissociate the AuNP aggregates as a function of target protease detection, i.e., main protease (Mpro), a biomarker for severe acute respiratory syndrome coronavirus 2. The dissociation propensity depends on peptide length, hydrophilicity, charge, and ligand architecture. Finally, our dissociation strategy provides a rapid and distinct optical signal through Mpro cleavage with a detection limit of 12.3 nM in saliva. Our dissociation peptide effectively dissociates plasmonic assemblies in diverse matrices including 100% human saliva, urine, plasma, and seawater, as well as other types of plasmonic nanoparticles such as silver. Our peptide-enabled dissociation platform provides a simple, matrix-insensitive, and versatile method for protease sensing.

To list or not to list? The value and detriment of freelisting in ethnobotanical studies.

Although freelisting and semi-structured interviews are widespread methods in ethnobotany, few studies quantitatively examine how these methods may bias results. Using a comprehensive ethnobotanical inventory of palm species, uses and names in the Chácobo tribe of Bolivia, we show that interviews elicit more items than freelists, but the effect is sensitive to sample size, item type and data categorization. This implies that even subtle methodological choices may greatly affect reported results.

Who should conduct ethnobotanical studies? Effects of different interviewers in the case of the Chácobo Ethnobotany project, Beni, Bolivia.

BACKGROUND: That the answers elicited through interviews may be influenced by the knowledge of the interviewer is accepted across disciplines. However, in ethnobotany, there is little evidence to quantitatively assess what impact this effect may have. We use the results of a large study of traditional ecological knowledge (TEK) of plant use of the Chácobo and Pacahuara of Beni, Bolivia, to explore the effects of interviewer identity and knowledge upon the elicited plant species and uses. METHODS: The Chácobo are a Panoan speaking tribe of about 1000 members (300+ adults) in Beni, Bolivia. Researchers have collected anthropological and ethnobotanical data from the Chácobo for more than a century. Here, we present a complete ethnobotanical inventory of the entire adult Chácobo population, with interviews and plant collection conducted directly by Chácobo counterparts, with a focus on the effects caused by external interviewers. RESULTS: Within this large study, with a unified training for interviewers, we did find that different interviewers did elicit different knowledge sets, that some interviewers were more likely to elicit knowledge similar to their own, and that participants interviewed multiple times often gave information as different as that from two randomly chosen participants. CONCLUSIONS: Despite this, we did not find this effect to be overwhelming-the amount of knowledge an interviewer reported on the research subject had comparatively little effect on the amount of knowledge that interviewer recorded from others, and even those interviewers who tended to elicit similar answers from participants also elicited a large percentage of novel information.

Traditional knowledge hiding in plain sight - twenty-first century ethnobotany of the Chácobo in Beni, Bolivia.

BACKGROUND: The Chácobo are a Panoan speaking tribe of about 1000 members (300+ adults) in Beni, Bolivia. Originally nomadic, the Chácabo were relocated to their current main location in the 1960s. Researchers have visited the Chácabo since 1911. A first more detailed anthropological report exists from the late 1960s, and ecological-ethnobotanical studies were conducted in the 1980s and 1990s. The presented work represents a complete ethnobotanical inventory of the entire adult Chácobo population, with interviews and plant collection conducted directly by Chácobo counterparts. METHODS: Based on previous reports and our preliminary studies, we hypothesized that twenty-first century Chácobo plant use centered on income generation, and that traditional plant use related to household utensils, medicine and traditional crop varieties had almost disappeared. To test this hypothesis, we started the "Chácobo Ethnobotany Project," training 10 indigenous Chácobo participants in ethnobotanical interview and plant collection techniques, in order to more fully document Chácobo knowledge and avoid the influence of foreign interviewers. RESULTS: Our study found 331 useful plant species in 241genera of 95 plant families, with leaves, roots and bark being the most commonly used plant parts The comprehensive documentation that these methods enabled completely nullified our initial hypothesis of knowledge loss. Traditional crop varieties are still widely grown and traditional knowledge is alive. Moreover, it is being actively recuperated in certain domains by the younger generation. Most Chácobo know, and can name, traditional utensils and tools, although only the older generation has still the skills to manufacture them. While many Chácobo still know the names and uses of medicinal species, the younger generation is however often unsure how to identify them. CONCLUSIONS: In this paper we illustrate the complexity of perspectives on knowledge at different ages, and the persistence of knowledge over almost a century. We found that traditional knowledge was only partially affected by the processes of exposure to a market economy, and that different knowledge domains experienced different trends as a result of these changes. Overall knowledge was widely distributed, and we did not observe a directional knowledge loss. We stress the importance to not directly conclude processes of knowledge loss, cultural erosion or acculturation when comparing the knowledge of different age groups.

Lactancia materna como factor protector para enfermedades prevalentes en niños hasta de 5 años de edad en algunas instituciones educativas de Colombia 2009: estudio de corte transversal / A cross-sectional study of maternal breastfeeding as protection factor for prevalent diseases in children up to 5 years of age in some Colombian educational institutions, 2009

Objetivo: establecer la frecuencia de empleo y explorar el papel que tiene la lactancia materna exclusiva hasta los 6 meses como factor protector para enfermedades prevalentes, en niños hasta de 5 años de edad en una determinada población colombiana. Materiales y métodos: se realizó un estudio de corte transversal en algunas instituciones educativas a nivel de jardín infantil de los municipios de Palestina, Ibagué y Pereira (Colombia). La escogencia de la población se efectuó mediante un muestreo por conveniencia. Se evaluaron las características basales, tipo de alimentación, tiempo de lactancia materna, tiempo de alimentación complementaria, enfermedades respiratorias, apendicitis, enfermedad diarreica aguda, diabetes mellitus, dermatitis, reflujo gastroesofágico, desnutrición, obesidad y afección cardiorrespiratoria. Resultados: participaron en el estudio 311 niños. Se encontró una frecuencia de lactancia materna del 92% (98,1% Ibagué, 90,5% Pereira, 87,9% Palestina) y una asociación significativa entre la lactancia materna y bronquiolitis, reflujo gastroesofágico, síndrome bronco obstructivo, desnutrición y afección cardiorrespiratoria. Conclusiones: se confirma la importancia de la lactancia materna como factor protector para enfermedades prevalentes en la infancia.

Objective: establishing the frequency of use and exploring the role of exclusive maternal breastfeeding for up to six months as a protection factor against prevalent diseases in children up to 5 years of age in a determined Colombian population. Materials and methods: a cross-sectional study was carried out in some kindergartens in the towns of Palestina, Ibagué and Pereira (Colombia). The study population was chosen by convenience sampling. Base characteristics such as type of feeding, maternal breastfeeding time, complementary feeding time, respiratory disease, appendicitis, acute diarrheic disease, diabetes mellitus, dermatitis, gastroesophageal reflux, malnutrition, obesity and cardiorespiratory affection were evaluated. Results: 311 children participated in the study. 92% maternal breastfeeding frequency was found (98.1% in Ibagué, 90.5% Pereira, 87.9% in Palestina) and a significant association was found between maternal breastfeeding and bronchiolitis, gastroesophageal reflux, broncho-obstructive syndrome, malnutrition and cardiorespiratory affection. Conclusions: the importance of maternal breastfeeding was confirmed as a protection factor for prevalent diseases during infancy.

Nitric oxide sensitizes tumor cells to TRAIL-induced apoptosis via inhibition of the DR5 transcription repressor Yin Yang 1.

Treatment of TRAIL-resistant tumor cells with the nitric oxide donor DETANONOate sensitizes the tumor cells to TRAIL-induced apoptosis concomitantly with DR5 upregulation. The mechanism of sensitization was examined based on the hypothesis that DETANONOate inhibits a transcription repressor Yin Yang 1 (YY1) that negatively regulates DR5 transcription. Treatment of the prostate carcinoma cell lines with DETANONOate inhibited both NF-kappaB and YY1 DNA-binding activities concomitantly with upregulation of DR5 expression. The direct role of YY1 in the regulation of TRAIL resistance was demonstrated in cells treated with YY1 siRNA resulting in TRAIL-induced apoptosis. The role of YY1 in the transcriptional regulation of DR5 was examined in cells treated with a DR5 luciferase reporter system (pDR5) and two constructs, namely, the pDR5/-605 construct with a deletion of the putative YY1 DNA-binding region (-1224 to -605) and a construct pDR5-YY1 with a mutation of the YY1 DNA-binding site. A significant (3-fold) augmentation of luciferase activity over baseline transfection with pDR5 was observed in cells transfected with the modified constructs. ChIP analysis corroborated the YY1 binding to the DR5 promoter. In vivo, tissues from nude mice bearing the PC-3 xenograft and treated with DETANONOate showed inhibition of YY1 and upregulation of DR5. The present findings demonstrate that YY1 negatively regulates DR5 transcription and expression and these correlated with resistance to TRAIL-induced apoptosis. DETANONOate inhibits both NF-kappaB and YY1 and in combination with TRAIL reverses tumor cell resistance to TRAIL apoptosis.