Nearly all mass gathering events worldwide were banned at the beginning of the COVID-19 pandemic, as they were suspected of presenting a considerable risk for the transmission of SARS-CoV-2. We ...investigated the risk of transmitting SARS-CoV-2 by droplets and aerosols during an experimental indoor mass gathering event under three different hygiene practices, and used the data in a simulation study to estimate the resulting burden of disease under conditions of controlled epidemics. Our results show that the mean number of measured direct contacts per visitor was nine persons and this can be reduced substantially by appropriate hygiene practices. A comparison of two versions of ventilation with different air exchange rates and different airflows found that the system which performed worst allowed a ten-fold increase in the number of individuals exposed to infectious aerosols. The overall burden of infections resulting from indoor mass gatherings depends largely on the quality of the ventilation system and the hygiene practices. Presuming an effective ventilation system, indoor mass gathering events with suitable hygiene practices have a very small, if any, effect on epidemic spread.
Soil nutrient acquisition and exchanges through symbiotic plant–fungus interactions in the rhizosphere are key features for the current agricultural and environmental challenges. Improved crop yield ...and plant mineral nutrition through a fungal symbiont has been widely described. In return, the host plant supplies carbon substrates to its fungal partner. We review here recent progress on molecular players of membrane transport involved in nutritional exchanges between mycorrhizal plants and fungi. We cover the transportome, from the transport proteins involved in sugar fluxes from plants towards fungi, to the uptake from the soil and exchange of nitrogen, phosphate, potassium, sulfate, and water. Together, these advances in the comprehension of the mycorrhizal transportome will help in developing the future engineering of new agro-ecological systems.
Plant growth and development are highly dependent on rhizosphere nutrient availability which is often a limiting factor. This constraint has forced land plants to evolve various strategies, including beneficial interactions with soil microorganisms.
The symbiotic interactions between plant roots and fungi, termed mycorrhizal symbiosis, provide reciprocal benefits for both partners, as for instance for the plant partner the acquisition of nitrogen (N), phosphate (P), potassium (K), and sulfate (S), the primary macronutrients used in plant fertilizer.
Plant and fungal transport systems display ‘mycorrhiza-specific’ and ‘fine-tuning’ regulation to control nutrient fluxes towards the symbiotic interface, delimiting the site of reciprocal nutrient exchanges between the partners.
The selection and engineering of mycorrhizal partners based on the plant and fungal transportome, targeting the key transporters resulting from the massive generation and analysis of ‘omics’ data, will ensure agro-ecological improvement of crop nutrition.
Abstract Objective A fully automated method for reducing EOG artifacts is presented and validated. Methods The correction method is based on regression analysis and was applied to 18 recordings with ...22 channels and approx. 6 min each. Two independent experts scored the original and corrected EEG in a blinded evaluation. Results The expert scorers identified in 5.9% of the raw data some EOG artifacts; 4.7% were corrected. After applying the EOG correction, the expert scorers identified in another 1.9% of the data some EOG artifacts, which were not recognized in the uncorrected data. Conclusions The advantage of a fully automated reduction of EOG artifacts justifies the small additional effort of the proposed method and is a viable option for reducing EOG artifacts. The method has been implemented for offline and online analysis and is available through BioSig, an open source software library for biomedical signal processing. Significance Visual identification and rejection of EOG-contaminated EEG segments can miss many EOG artifacts, and is therefore not sufficient for removing EOG artifacts. The proposed method was able to reduce EOG artifacts by 80%.
In prospective memory tasks different kinds of load can occur. Adding a prospective memory task can impose a load on ongoing task performance. Adding ongoing task load (OTL) can affect prospective ...memory performance. The existence of multiple target events increases prospective load (PL) and adding complexity to the to-be-remembered action increases retrospective load (RL). In two experiments, we systematically examined the effects of these different types of load on prospective memory performance. Results showed an effect of PL on costs in the ongoing task for categorical targets (Experiment 2), but not for specific targets (Experiment 1). RL and OTL both affected remembering the retrospective component of the prospective memory task. We suggest that PL can enhance costs in the ongoing task due to additional monitoring requirements. RL and OTL seem to impact the division of resources between the ongoing task and retrieval of the retrospective component, which may affect disengagement from the ongoing task. In general, the results demonstrate that the different types of load affect prospective memory differentially.
Brain Research Institute, University of Zurich and Swiss Federal
Institute of Technology Zurich; and Molecular Biology Laboratory,
Department of Pathology, University Hospital, Zurich,
Switzerland
...Bandtlow, Christine E. and
Dieter R. Zimmermann.
Proteoglycans in the Developing Brain: New Conceptual
Insights for Old Proteins. Physiol. Rev. 80: 1267-1290, 2000. Proteoglycans
are a heterogeneous class of proteins bearing sulfated
glycosaminoglycans. Some of the proteoglycans have distinct core
protein structures, and others display similarities and thus may be
grouped into families such as the syndecans, the glypicans, or the
hyalectans (or lecticans). Proteoglycans can be found in almost all
tissues being present in the extracellular matrix, on cellular
surfaces, or in intracellular granules. In recent years, brain
proteoglycans have attracted growing interest due to their highly
regulated spatiotemporal expression during nervous system development
and maturation. There is increasing evidence that different
proteoglycans act as regulators of cell migration, axonal pathfinding,
synaptogenesis, and structural plasticity. This review summarizes the
most recent data on structures and functions of brain proteoglycans and
focuses on new physiological concepts for their potential roles in the
developing central nervous system.
Ectomycorrhizal (ECM) fungi are associated with the roots of woody plants in temperate and boreal forests and help them to acquire water and nutrients, particularly phosphorus (P). However, the ...molecular mechanisms responsible for the transfer of P from the fungus to the plant in ectomycorrhizae are still poorly understood. In the model association between the ECM fungus
and its host plant
, we have shown that the fungus, which possesses three H+:Pi symporters (HcPT1.1, HcPT1.2 and HcPT2), expresses mainly
and
in the extraradical and intraradical hyphae of ectomycorrhizae to transport P from the soil to colonized roots. The present study focuses on the role of the HcPT1.1 protein in plant P nutrition, in function of P availability. We artificially overexpressed this P transporter by fungal Agrotransformation and investigated the effect of the different lines, wild-type and transformed ones, on plant P accumulation, the distribution of HcPT1.1 and HcPT2 proteins in ectomycorrhizae by immunolocalization, and 32P efflux in an experimental system mimicking intraradical hyphae. Surprisingly, we showed that plants interacting with transgenic fungal lines overexpressing
did not accumulate more P in their shoots than plants colonized with the control ones. Although the overexpression of
did not affect the expression levels of the other two P transporters in pure cultures, it induced a strong reduction in HcPT2 proteins in ectomycorrhizae, particularly in intraradical hyphae, but still improved the P status of host plant shoots compared with non-mycorrhizal plants. Finally, 32P efflux from hyphae was higher in lines overexpressing
than in the control ones. These results suggest that a tight regulation and/or a functional redundancy between the H+:Pi symporters of
might exist to ensure a sustainable P delivery to
.
The unexpected location of VvK5.1 expression detected in the lateral root primordium, berry phloem and pistil provides new insights into the roles that this outward channel type can play in plants.
...Abstract
Grapevine (Vitis vinifera L.), one of the most important fruit crops, is a model plant for studying the physiology of fleshy fruits. Here, we report on the characterization of a new grapevine Shaker-type K+ channel, VvK5.1. Phylogenetic analysis revealed that VvK5.1 belongs to the SKOR-like subfamily. Our functional characterization of VvK5.1 in Xenopus oocytes confirms that it is an outwardly rectifying K+ channel that displays strict K+ selectivity. Gene expression level analyses by real-time quantitative PCR showed that VvK5.1 expression was detected in berries, roots, and flowers. In contrast to its Arabidopsis thaliana counterpart that is involved in K+ secretion in the root pericycle, allowing root to shoot K+ translocation, VvK5.1 expression territory is greatly enlarged. Using in situ hybridization we showed that VvK5.1 is expressed in the phloem and perivascular cells of berries and in flower pistil. In the root, in addition to being expressed in the root pericycle like AtSKOR, a strong expression of VvK5.1 is detected in small cells facing the xylem that are involved in lateral root formation. This fine and selective expression pattern of VvK5.1 at the early stage of lateral root primordia supports a role for outward channels to switch on cell division initiation.
Editorial on the Research Topic Importance of root symbiomes for plant nutrition: new insights, perspectives and future challenges, volume II Frontiers in Plant Science frontiersin.org 01
Plants interact with a plethora of soil microbes that help them to acquire nutritional resources, to be protected against pathogens, and to face challenging and fluctuating external conditions. ...Understanding how the microbiota of roots and rhizospheres is shaped and conserved by host plants, and how it changes in response to genetic and environmental pressures, is crucial for the preservation of natural ecosystems and to harness its potential for the development of novel strategies in agroecosystems. This Research Topic presents a series of articles that summarizes the latest research updates on the impact of the plant microbiota and its specific symbionts i.e., arbuscular mycorrhizal (AM) and ectomycorrhizal (ECM) fungi, nitrogen-fixing rhizobia, and plant growth-promoting rhizobacteria (PGPR) on plant performance and resilience, and the external factors that influence plant microbiota assembly. Novel next generation sequencing technologies and analytical platforms provide us with more insights into the plant microbiome. In this Research Topic, Ma et al. discussed the development and potential use of single-cell RNA-sequencing technology in the area of plant microbiomes. Although still challenging to apply routinely, it opens the way toward the discovery of very specific and localized functions of bacterial communities in plant microbiota. Multiple studies have shown that the microbiome composition differs among cultivars of a given plant species, such as corn (Walters et al., 2018), cotton (Wei et al., 2019), or grape (Mezzasalma et al., 2018). Using three switchgrass cultivars grown under various conditions (i.e., monoculture, intraspecific, or interspecific mixtures), Revillini et al. showed that plant diversity influences the structure of AM fungal and bacterial communities in the root rhizosphere, but that nitrogen fertilization only affects the composition of the AM community but not of the rhizobacterial community. These findings highlight the importance of adapted cultivar and management practices in agricultural settings to maintain optimal microbiomes. Although it is described that herbivores can also influence the leaf microbiota composition (Humphrey and Whiteman, 2020), their impact on root microbiota assembly, and particularly on AM fungi, is still unclear. In this Research Topic, Wilkinson et al. demonstrated that the inoculation with aphids does not alter the AMcolonization and community composition in barley, but that the formation of fungal vesicles and the relative abundance of some fungal species in these communities is affected.
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