Microbial siderophore-mediated transport

2002 ◽  
Vol 30 (4) ◽  
pp. 691-696 ◽  
Author(s):  
G. Winkelmann
Keyword(s):  
Transport Properties ◽  
Present Review ◽  
Iron Availability ◽  
Iron Chelates ◽  
Structural Details ◽  
Bacteria And Fungi ◽  
And Function

Microbial iron chelates, called siderophores, are synthesized by bacteria and fungi in response to low iron availability in the environment. The present review summarizes structural details of siderophore ligands with respect to their transport properties. This presentation is largely centred on the occurrence and function of siderophores in the various bacterial and fungal genera.

Form and function of eukaryotic unstable non-coding RNAs

2012 ◽  
Vol 40 (4) ◽  
pp. 836-841 ◽  
Author(s):  
Jonathan Houseley
Keyword(s):  
Unknown Function ◽  
Budding Yeast ◽  
Rna Degradation ◽  
Present Review ◽  
Form And Function ◽  
Non Coding Rna ◽  
Non Coding Rnas ◽  
Higher Eukaryotes ◽  
And Function

Unstable non-coding RNAs are produced from thousands of loci in all studied eukaryotes (and also prokaryotes), but remain of largely unknown function. The present review summarizes the mechanisms of eukaryotic non-coding RNA degradation and highlights recent findings regarding function. The focus is primarily on budding yeast where the bulk of this research has been performed, but includes results from higher eukaryotes where available.

scholarly journals Identification and functional characterization of the Piezo1 channel pore domain

2020 ◽  
pp. jbc.RA120.015905
Author(s):  
Elena D Nosyreva ◽  
David Thompson ◽  
Ruhma Syeda
Keyword(s):  
Functional Characterization ◽  
Functional Study ◽  
Heat Sensation ◽  
Physiological Processes ◽  
Structural Details ◽  
Functional Understanding ◽  
And Function ◽  
Downstream Processes ◽  
Pore Domain ◽  
First Time

Mechanotransduction is the process by which cells convert physical forces into electro-chemical responses. On a molecular scale these forces are detected by mechanically activated ion channels, which constitute the basis for hearing, touch, pain, cold and heat sensation amongst other physiological processes. Exciting high-resolution structural details of these channels are currently emerging that will eventually allow us to delineate the molecular determinants of gating and ion permeation. However, our structural-functional understanding across the family remains limited. Piezo1 is one of the largest and least understood of these channels, with various structurally identified features within its trimeric assembly. This study seeks to determine the modularity and function of Piezo1 channels by constructing deletion proteins guided by cryo EM structural knowledge. Our comprehensive functional study identified, for the first time, the minimal amino acid sequence of the full-length Piezo1 that can fold and function as the channel’s pore domain between E2172 and the last residue E2547. While, the addition of an anchor region has no effect on permeation properties. The Piezo1 pore domain is not pressure sensitive and the appending of Piezo Repeat-A did not restore pressure-dependent gating, hence the sensing module must exist between residues 1-1952. Our efforts delineating the permeation and gating regions within this complex ion channel have implications in identifying small molecules that exclusively regulate the activity of the channel’s pore module to influence mechanotransduction and downstream processes.

scholarly journals Astrocytes: News about Brain Health and Diseases

Biomedicines ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 394
Author(s):  
Jacopo Meldolesi
Keyword(s):  
Glial Cells ◽  
Present State ◽  
Cell Types ◽  
Present Review ◽  
Brain Health ◽  
Traumatic Injuries ◽  
Future Studies ◽  
Brain Physiology ◽  
And Function

Astrocytes, the most numerous glial cells in the brains of humans and other mammalian animals, have been studied since their discovery over 100 years ago. For many decades, however, astrocytes were believed to operate as a glue, providing only mechanical and metabolic support to adjacent neurons. Starting from a “revolution” initiated about 25 years ago, numerous astrocyte functions have been reconsidered, some previously unknown, others attributed to neurons or other cell types. The knowledge of astrocytes has been continuously growing during the last few years. Based on these considerations, in the present review, different from single or general overviews, focused on six astrocyte functions, chosen due in their relevance in both brain physiology and pathology. Astrocytes, previously believed to be homogeneous, are now recognized to be heterogeneous, composed by types distinct in structure, distribution, and function; their cooperation with microglia is known to govern local neuroinflammation and brain restoration upon traumatic injuries; and astrocyte senescence is relevant for the development of both health and diseases. Knowledge regarding the role of astrocytes in tauopathies and Alzheimer’s disease has grow considerably. The multiple properties emphasized here, relevant for the present state of astrocytes, will be further developed by ongoing and future studies.

Pseudoproteases: mechanisms and function

2015 ◽  
Vol 468 (1) ◽  
pp. 17-24 ◽  
Author(s):  
Simone L. Reynolds ◽  
Katja Fischer
Keyword(s):  
Structure Function ◽  
Mode Of Action ◽  
Immune Modulation ◽  
Therapeutic Targets ◽  
Structure Functions ◽  
Present Review ◽  
Biological Processes ◽  
And Function ◽  
Classification Structure

Catalytically inactive enzymes (also known as pseudoproteases, protease homologues or paralogues, non-peptidase homologues, non-enzymes and pseudoenzymes) have traditionally been hypothesized to act as regulators of their active homologues. However, those that have been characterized demonstrate that inactive enzymes have an extensive and expanding role in biological processes, including regulation, inhibition and immune modulation. With the emergence of each new genome, more inactive enzymes are being identified, and their abundance and potential as therapeutic targets has been realized. In the light of the growing interest in this emerging field the present review focuses on the classification, structure, function and mechanism of inactive enzymes. Examples of how inactivity is defined, how this is reflected in the structure, functions of inactive enzymes in biological processes and their mode of action are discussed.

scholarly journals Bacterial flagellar motor

2008 ◽  
Vol 41 (2) ◽  
pp. 103-132 ◽  
Author(s):  
Yoshiyuki Sowa ◽  
Richard M. Berry
Keyword(s):  
Single Molecule ◽  
Cell Envelope ◽  
Molecular Motor ◽  
Motive Force ◽  
Flagellar Motor ◽  
Large Size ◽  
Structural Details ◽  
Bacterial Flagellar Motor ◽  
And Function ◽  
Rotary Motor

AbstractThe bacterial flagellar motor is a reversible rotary nano-machine, about 45 nm in diameter, embedded in the bacterial cell envelope. It is powered by the flux of H+or Na+ions across the cytoplasmic membrane driven by an electrochemical gradient, the proton-motive force or the sodium-motive force. Each motor rotates a helical filament at several hundreds of revolutions per second (hertz). In many species, the motor switches direction stochastically, with the switching rates controlled by a network of sensory and signalling proteins. The bacterial flagellar motor was confirmed as a rotary motor in the early 1970s, the first direct observation of the function of a single molecular motor. However, because of the large size and complexity of the motor, much remains to be discovered, in particular, the structural details of the torque-generating mechanism. This review outlines what has been learned about the structure and function of the motor using a combination of genetics, single-molecule and biophysical techniques, with a focus on recent results and single-molecule techniques.

scholarly journals Analysis of Ficus hirta Fig Endosymbionts Diversity and Species Composition

Diversity ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 636
Author(s):  
Yifeng Liu ◽  
Songle Fan ◽  
Hui Yu
Keyword(s):  
High Throughput Sequencing ◽  
Biological Database ◽  
Fig Wasp ◽  
Fig Wasps ◽  
Function Annotation ◽  
History Of ◽  
Ficus Hirta ◽  
Bacteria And Fungi ◽  
And Function ◽  
Confined Environment

Endosymbionts living in plants and insects are pervasive. Ficus (Moraceae) has very special inflorescences (which we also call figs) enclosed like an urn, and such inflorescence is usually parasitized by fig wasps. Ficus breeds fig wasp larvae in its figs and adult fig wasps pollinate for Ficus, Ficus and its obligated pollinator formed fig-fig wasp mutualism. Previous studies have found that this confined environment in figs may have provided protection for fig wasps and that this has left some imprints on the genome of fig wasps during the coevolution history of figs and fig wasps. Research on the diversity of both bacteria and fungi in figs are fewer. Our study explored the diversity of endosymbionts in Ficus hirta figs. We utilized high-throughput sequencing and biological database to identify the specific microorganism in figs, then conducted microorganism communities’ diversity analysis and function annotation analysis. As a result, we identified the dominant endosymbionts in figs, mainly some insect internal parasitic bacteria and fungi, plant pathogen, endophytes, and saprotroph. Then we also found bacteria in Ficus hirta figs were more diversified than fungi, and bacteria communities in female figs and functional male figs were different. These findings may give us more insight into the coevolution and interaction among endosymbiont, fig, and fig wasp.

scholarly journals Streptomycesvolatile compounds influence exploration and microbial community dynamics by altering iron availability

2018 ◽  
Author(s):  
Stephanie E. Jones ◽  
Christine A. Pham ◽  
Joseph McKillip ◽  
Matthew Zambri ◽  
Erin E. Carlson ◽  
...  
Keyword(s):  
Soil Bacteria ◽  
Community Dynamics ◽  
Critical Role ◽  
Iron Chelators ◽  
Iron Availability ◽  
Microbial Community Dynamics ◽  
Volatile Organic ◽  
Soil Bacteria And Fungi ◽  
New Form ◽  
Bacteria And Fungi

ABSTRACTBacteria and fungi produce a wide array of volatile organic compounds (VOCs), and these can act as infochemicals or as competitive tools. Recent work has shown that the VOC trimethylamine (TMA) can promote a new form ofStreptomycesgrowth, termed ‘exploration’. Here, we report that TMA also serves to alter nutrient availability in the area surrounding exploring cultures: TMA dramatically increases the environmental pH, and in doing so, reduces iron availability. This, in turn, compromised the growth of other soil bacteria and fungi. In contrast,Streptomycesthrives in these iron-depleted niches by secreting a suite of differentially modified siderophores, and by upregulating genes associated with siderophore uptake. Further reducing iron levels by siderophore piracy, limiting siderophore uptake, or growing cultures in the presence of iron chelators, unexpectedly enhanced exploration. Our work reveals a new role for VOCs in modulating iron levels in the environment, and implies a critical role for VOCs in modulating the behaviour of microbes and the makeup of their communities.

scholarly journals StreptomycesVolatile Compounds Influence Exploration and Microbial Community Dynamics by Altering Iron Availability

mBio ◽  
2019 ◽  
Vol 10 (2) ◽  
Author(s):  
Stephanie E. Jones ◽  
Christine A. Pham ◽  
Matthew P. Zambri ◽  
Joseph McKillip ◽  
Erin E. Carlson ◽  
...  
Keyword(s):  
Microbial Community ◽  
Nutrient Availability ◽  
Iron Uptake ◽  
Community Dynamics ◽  
Critical Role ◽  
Iron Availability ◽  
Interspecies Interactions ◽  
Community Interactions ◽  
Content Type ◽  
Bacteria And Fungi

ABSTRACTBacteria and fungi produce a wide array of volatile organic compounds (VOCs), and these can act as chemical cues or as competitive tools. Recent work has shown that the VOC trimethylamine (TMA) can promote a new form ofStreptomycesgrowth, termed “exploration.” Here, we report that TMA also serves to alter nutrient availability in the area surrounding exploring cultures: TMA dramatically increases the environmental pH and, in doing so, reduces iron availability. This, in turn, compromises the growth of other soil bacteria and fungi. In response to this low-iron environment,Streptomyces venezuelaesecretes a suite of differentially modified siderophores and upregulates genes associated with siderophore uptake. Further reducing iron levels by limiting siderophore uptake or growing cultures in the presence of iron chelators enhanced exploration. Exploration was also increased whenS. venezuelaewas grown in association with the related low-iron- and TMA-tolerantAmycolatopsisbacteria, due to competition for available iron. We are only beginning to appreciate the role of VOCs in natural communities. This work reveals a new role for VOCs in modulating iron levels in the environment and implies a critical role for VOCs in modulating the behavior of microbes and the makeup of their communities. It further adds a new dimension to our understanding of the interspecies interactions that influenceStreptomycesexploration and highlights the importance of iron in exploration modulation.IMPORTANCEMicrobial growth and community interactions are influenced by a multitude of factors. A new mode ofStreptomycesgrowth—exploration—is promoted by interactions with the yeastSaccharomycescerevisiaeand requires the emission of trimethylamine (TMA), a pH-raising volatile compound. We show here that TMA emission also profoundly alters the environment around exploring cultures. It specifically reduces iron availability, and this in turn adversely affects the viability of surrounding microbes. Paradoxically,Streptomycesbacteria thrive in these iron-depleted niches, both rewiring their gene expression and metabolism to facilitate iron uptake and increasing their exploration rate. Growth in close proximity to other microbes adept at iron uptake also enhances exploration. Collectively, the data from this work reveal a new role for bacterial volatile compounds in modulating nutrient availability and microbial community behavior. The results further expand the repertoire of interspecies interactions and nutrient cues that impactStreptomycesexploration and provide new mechanistic insight into this unique mode of bacterial growth.

scholarly journals Microbial abundance, composition, and function in nectar are shaped by flower visitor identity

2020 ◽  
Vol 96 (3) ◽  
Author(s):  
Megan M Morris ◽  
Natalie J Frixione ◽  
Alexander C Burkert ◽  
Elizabeth A Dinsdale ◽  
Rachel L Vannette
Keyword(s):  
Community Assembly ◽  
Culturable Bacteria ◽  
Microbial Abundance ◽  
Floral Nectar ◽  
Shotgun Metagenomics ◽  
Carpenter Bees ◽  
Vector Identity ◽  
Bacteria And Fungi ◽  
And Function ◽  
Nectar Robbers

ABSTRACT Microbial dispersal is essential for establishment in new habitats, but the role of vector identity is poorly understood in community assembly and function. Here, we compared microbial assembly and function in floral nectar visited by legitimate pollinators (hummingbirds) and nectar robbers (carpenter bees). We assessed effects of visitation on the abundance and composition of culturable bacteria and fungi and their taxonomy and function using shotgun metagenomics and nectar chemistry. We also compared metagenome-assembled genomes (MAGs) of Acinetobacter, a common and highly abundant nectar bacterium, among visitor treatments. Visitation increased microbial abundance, but robbing resulted in 10× higher microbial abundance than pollination. Microbial communities differed among visitor treatments: robbed flowers were characterized by predominant nectar specialists within Acetobacteraceae and Metschnikowiaceae, with a concurrent loss of rare taxa, and these resulting communities harbored genes relating to osmotic stress, saccharide metabolism and specialized transporters. Gene differences were mirrored in function: robbed nectar contained a higher percentage of monosaccharides. Draft genomes of Acinetobacter revealed distinct amino acid and saccharide utilization pathways in strains isolated from robbed versus pollinated flowers. Our results suggest an unrecognized cost of nectar robbing for pollination and distinct effects of visitor type on interactions between plants and pollinators. Overall, these results suggest vector identity is an underappreciated factor structuring microbial community assembly and function.

The Application of the Rorschach Inkblot Test in the Study of Neural and Cognitive Aging

2020 ◽  
Vol 41 (1) ◽  
pp. 1-18 ◽  
Author(s):  
Eamonn Arble ◽  
Steven W. Steinert ◽  
Ana M. Daugherty
Keyword(s):  
Cognitive Function ◽  
Cognitive Aging ◽  
Mirror Neuron ◽  
Present Review ◽  
Age Related ◽  
Brain Structure And Function ◽  
Rorschach Inkblot Test ◽  
Cortical Regions ◽  
Inkblot Test ◽  
And Function

Abstract. The Rorschach Inkblot test has been adopted and adapted by many researchers to assess and predict different aspects of human experience and cognitive performance. The present review examines research that incorporates the Rorschach to evaluate neural and cognitive aging as well as decline in age-related disease. Specifically, differences in amygdala and cortical regions, as well as mirror neuron and asymmetrical hemisphere activity that correlate with specific responses to Rorschach stimuli are discussed in the context of typical changes in brain structure and function in the course of aging. In addition, the present review provides a proposed framework for expanding the use of the Rorschach to evaluate other domains of neural and cognitive function. The authors conclude that, despite a need for increased research, the Rorschach is a viable measure to evaluate certain aspects of cognitive function and decline throughout the lifespan.

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