1,720,957 research outputs found
Life on the dry side: a roadmap to understanding desiccation tolerance and accelerating translational applications
Get PDFTo thrive in extreme conditions, organisms have evolved a diverse arsenal of adaptations that confer resilience. These species, their traits, and the mechanisms underlying them comprise a valuable resource that can be mined for numerous conceptual insights and applied objectives. One of the most dramatic adaptations to water limitation is desiccation tolerance. Understanding the mechanisms underlying desiccation tolerance has important potential implications for medicine, biotechnology, agriculture, and conservation. However, progress has been hindered by a lack of standardization across sub-disciplines, complicating the integration of data and slowing the translation of basic discoveries into practical applications. Here, we synthesize current knowledge on desiccation tolerance across evolutionary, ecological, physiological, and cellular scales to provide a roadmap for advancing desiccation tolerance research. We also address critical gaps and technical roadblocks, highlighting the need for standardized experimental practices, improved taxonomic sampling, and the development of new tools for studying biology in a dry state. We hope that this perspective can serve as a roadmap to accelerating research breakthroughs and unlocking the potential of desiccation tolerance to address global challenges related to climate change, food security, and health
Determination of multi-mycotoxin dietaries exposure level in humans in rural area of Limpopo Province, South Africa
No full textAbstract: Mycotoxins are secondary metabolites that are produced by filamentous mycotoxigenic fungi belonging to the Alternaria, Aspergillus, Fusarium and Penicillium genera. Agricultural grains, such as maize, sorghum and wheat are commonly consumed and classified as staple foodstuffs in South Africa, but known to be prone to fungal infestation and subsequent mycotoxin contamination. Hence, there is a crucial need to frequently monitor the levels of this food contaminant, to mitigate against exposure to its harmful effects toward humans. Multi-class mycotoxins were extracted from the food samples and analysed using liquid chromatographytandem mass spectrometry (LC-MS/MS). The adopted extraction method for maize, sorghum and wheat was comprehensively validated to determine method performance...M.Sc. (Biotechnology
The functional role of root-associated microbiome and metabolome of myrothamnus flabellifolia
No full textGlobal climate change is predicted to increase the occurrence and severity of drought, particularly in Africa, which will negatively impact crops and food production. Drought is the leading factor that adversely affects agricultural productivity and yield. Over the last four decades, extensive research on resurrection plants has yielded valuable insights into the mechanisms these plants employ to adapt during desiccation. Despite this, the role of the microbiome in desiccation tolerance, particularly in resurrection plants, remains a relatively unexplored area. Myrothamnus flabellifolia, a resurrection plant, stands out for its remarkable ability to endure severe desiccation, making it an ideal model for investigating the contributions of the plant microbiome to desiccation tolerance. Recognising the significance of root-associated microbes in stress tolerance opens up promising opportunities for enhancing drought resilience in crucial crops. However, the intricate dynamics of these interactions under severe water limitations have not been comprehensively investigated. Consequently, a primary objective of this study was to unravel the beneficial root-associated microbiome of M. flabellifolia and delineate their functions in the context of water deficit conditions. The intricate tripartite interplay involving plant roots, soil, and microorganisms remains enigmatic and demands further exploration. This study delved into the microbiome of belowground zones—bulk soil, rhizosphere soil, and endosphere of M. flabellifolia. Metagenomic analysis unveiled prevalent bacterial phyla (Acidobacteriota, Actinobacteriota, Chloroflexota, Planctomycetota, and Pseudomonadota) and dominant fungal phyla (Ascomycota and Basidiomycota) across all zones. While the bulk soil hosted numerous beneficial root-associated microbes, it exhibited lower functional diversity than the rhizosphere, which showcased the highest diversity of bacteria and fungi. Conversely, the endosphere exhibited lower microbial abundance and diversity. These findings suggest that M. flabellifolia may recruits soil microbes from bulk soil to rhizosphere and subsequently to the endosphere. Metatranscriptomic analysis has revealed crucial insights into the dynamics of plant-microbe interactions and the adaptive mechanisms employed by root-associated bacteria during desiccation in M. flabellifolia. The transcriptional activity of bacteria involved both monoderm and diderm lineages, consistent with the bacterial phyla identified in metagenomic analysis. However, the dominance of the Pseudomonadota phyla at the transcriptional activity was observed. Root-associated bacteria showed distinct transcriptional responses during dehydration and rehydration, suggesting dynamic shifts in microbial activity under fluctuating water availability. The expression of differentially expressed genes (DEGs) under dehydration conditions showcased the activation of proteins associated with antioxidant enzymes, molecular chaperones, protein kinases, and biosynthesis of sugars and amino acids. This implies a coordinated response to counteract damage and enhance survival. Intriguingly, the upregulation of genes encoding protein kinases, antioxidant enzymes, and trehalose synthase in root-associated bacteria reflects a common strategy for surviving desiccation stress. This suggests a potential case of convergent evolution in desiccation tolerance within microbiomes. The observed upregulation of genes related to plant growth and enhanced plant-microbe interaction under rehydration conditions suggests a resumption of microbial activity. Exploring the rhizosphere soil metabolome provided insights into the metabolic changes during drought stress in M. flabellifolia. Dehydrated rhizosphere soil exhibited increased levels of sugars (e.g., trehalose), organic acids (malic acid), and phytohormones (indole-3-acetic). Conversely, rehydrated rhizosphere samples showed significantly higher amino acid levels compared to desiccated samples, indicating a shift in biochemical processes in both the plant roots and rhizosphere microbiome. While rhizosphere metabolites are typically attributed to root exudates and microbial activity, this study revealed that many were possibly produced by rhizospheric bacteria. The upregulation of bacterial genes associated with metabolite biosynthesis under dehydration conditions, such as trehalose, further substantiated the the notion that drought serves as a selective pressure driving convergent evolution in species with desiccation tolerance. These findings indicates that the microbiome's adaptability under harsh environmental stress. Furthermore, inoculating maize plants with rhizospheric bacteria from M. flabellifolia's rhizosphere significantly improved drought tolerance, physiological, and morphological traits. The study concludes that root-associated microbiomes play a crucial role in M. flabellifolia's desiccation tolerance and plant growth-promoting microbes have a potential to be used as a biostimulant. This innovative research has implications for enhancing food security, developing resilient agricultural systems, and promoting sustainability
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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