Root hairs: the villi of plants

2021 ◽  
Author(s):  
Manuela Désirée Bienert ◽  
Lena M. Werner ◽  
Monika A. Wimmer ◽  
Gerd Patrick Bienert
Keyword(s):  
Nutrient Transport ◽  
Root Hairs ◽  
Physiological Role ◽  
Transport Proteins ◽  
Tubular Structures ◽  
Recent Developments ◽  
And Function ◽  
Development Structure ◽  
Efficient Transfer

Strikingly, evolution shaped similar tubular structures at the µm to mm scale in roots of sessile plants and in small intestines of mobile mammals to ensure an efficient transfer of essential nutrients from ‘dead matter' into biota. These structures, named root hairs (RHs) in plants and villi in mammals, numerously stretch into the environment, and extremely enlarge root and intestine surfaces. They are believed to forage for nutrients, and mediate their uptake. While the conceptional understanding of plant RH function in hydromineral nutrition seems clear, experimental evidence presented in textbooks is restricted to a very limited number of reference-nutrients. Here, we make an element-by-element journey through the periodic table and link individual nutrient availabilities to the development, structure/shape and function of RHs. Based on recent developments in molecular biology and the identification of mutants differing in number, length or other shape-related characteristics of RHs in various plant species, we present comprehensive advances in (i) the physiological role of RHs for the uptake of specific nutrients, (ii) the developmental and morphological responses of RHs to element availability and (iii) RH-localized nutrient transport proteins. Our update identifies crucial roles of RHs for hydromineral nutrition, mostly under nutrient and/or water limiting conditions, and highlights the influence of certain mineral availabilities on early stages of RH development, suggesting that nutritional stimuli, as deficiencies in P, Mn or B, can even dominate over intrinsic developmental programs underlying RH differentiation.

A critical physiological role of zinc in the structure and function of biomembranes

Life Sciences ◽  
1981 ◽  
Vol 28 (13) ◽  
pp. 1425-1438 ◽  
Author(s):  
William J. Bettger ◽  
Boyd L. O'Dell
Keyword(s):  
Physiological Role ◽  
Structure And Function ◽  
And Function

scholarly journals Equine Drug Transporters: A Mini-Review and Veterinary Perspective

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1064
Author(s):  
Brielle Rosa
Keyword(s):  
Drug Transport ◽  
Drug Disposition ◽  
Drug Transporters ◽  
Transport Proteins ◽  
Pharmacokinetic Parameters ◽  
Transporter Protein ◽  
Drug Pharmacokinetic ◽  
Species Specific ◽  
And Function

Xenobiotic transport proteins play an important role in determining drug disposition and pharmacokinetics. Our understanding of the role of these important proteins in humans and pre-clinical animal species has increased substantially over the past few decades, and has had an important impact on human medicine; however, veterinary medicine has not benefitted from the same quantity of research into drug transporters in species of veterinary interest. Differences in transporter expression cause difficulties in extrapolation of drug pharmacokinetic parameters between species, and lack of knowledge of species-specific transporter distribution and function can lead to drug–drug interactions and adverse effects. Horses are one species in which little is known about drug transport and transporter protein expression. The purpose of this mini-review is to stimulate interest in equine drug transport proteins and comparative transporter physiology.

New functions for old factors: the role of polyamines during the establishment of pregnancy

2019 ◽  
Vol 31 (7) ◽  
pp. 1228
Author(s):  
Jane C. Fenelon ◽  
Bruce D. Murphy
Keyword(s):  
Molecular Mechanisms ◽  
New Technologies ◽  
Alternative Pathway ◽  
Rapid Expansion ◽  
Polyamine Synthesis ◽  
Recent Developments ◽  
And Function ◽  
Implantation Period ◽  
Synthesis Regulation

Implantation is essential for the establishment of a successful pregnancy, and the preimplantation period plays a significant role in ensuring implantation occurs in a timely and coordinated manner. This requires effective maternal–embryonic signalling, established during the preimplantation period, to synchronise development. Although multiple factors have been identified as present during this time, the exact molecular mechanisms involved are unknown. Polyamines are small cationic molecules that are ubiquitously expressed from prokaryotes to eukaryotes. Despite being first identified over 300 years ago, their essential roles in cell proliferation and growth, including cancer, have only been recently recognised, with new technologies and interest resulting in rapid expansion of the polyamine field. This review provides a summary of our current understanding of polyamine synthesis, regulation and function with a focus on recent developments demonstrating the requirements for polyamines during the establishment of pregnancy up to the implantation stage, in particular the role of polyamines in the control of embryonic diapause and the identification of an alternative pathway for their synthesis in sheep pregnancy. This, along with other novel discoveries, provides new insights into the control of the peri-implantation period in mammals and highlights the complexities that exist in regulating this critical period of pregnancy.

Astrosclereids In Needles Of Old-Growth Douglas-Fir Trees

1999 ◽  
Vol 5 (S2) ◽  
pp. 1240-1241
Author(s):  
M. Apple ◽  
A. Soeldner ◽  
R. Hamill ◽  
K. Tiekotfer
Keyword(s):  
Pacific Northwest ◽  
Cell Walls ◽  
Douglas Fir ◽  
Old Growth ◽  
Mesophyll Cells ◽  
Mesophyll Tissue ◽  
The Pacific ◽  
And Function ◽  
Development Structure

Old-growth Douglas-fir trees in the Pacific Northwest are venerable giants that often live for 500 years and reach heights of over 75 meters. Their needles are relatively ephemeral and small but have the important role of interacting with the atmosphere in order to transpire and photosynthesize. Within the photosynthetic mesophyll tissue of Douglas-fir needles, there are large, non-living cells with lignified secondary cell walls that are known as astrosclereids. Apparent channels in the secondary wall may provide a route for exchange or transport of materials between the astrosclereid lumen and mesophyll cells or the vascular cylinder. Astrosclereids may be involvev d in storage of secondary metabolites such as tannin and may develop in response to fungi, mistletoe, or other pathogens. More knowledge is needed about the development, structure and function of astrosclereids.Needles were collected from sapling and old-growth Douglas-fir, Pseudotsuga menziesii, (Mirb.) Franco, trees at the Wind River Canopy Crane in Carson, Washington and from three sites in the Cascade Mountains of Oregon in 1997 and 1998.

scholarly journals Ca2+ signaling evoked by activation of Na+ channels and Na+/Ca2+ exchangers is required for GABA-induced NG2 cell migration

2009 ◽  
Vol 186 (1) ◽  
pp. 113-128 ◽  
Author(s):  
Xiao-ping Tong ◽  
Xiang-yao Li ◽  
Bing Zhou ◽  
Wanhua Shen ◽  
Zhi-jun Zhang ◽  
...  
Keyword(s):  
Gabaa Receptors ◽  
Physiological Role ◽  
Brain Regions ◽  
Na Channels ◽  
Typical Action ◽  
Sequential Activation ◽  
Ng2 Cells ◽  
And Function ◽  
Ca2 Channels

NG2 cells originate from various brain regions and migrate to their destinations during early development. These cells express voltage-gated Na+ channels but fail to produce typical action potentials. The physiological role of Na+ channels in these cells is unclear. We found that GABA induces membrane depolarization and Ca2+ elevation in NG2 cells, a process requiring activation of GABAA receptors, Na+ channels, and Na+/Ca2+ exchangers (NCXs), but not Ca2+ channels. We have identified a persistent Na+ current in these cells that may underlie the GABA-induced pathway of prolonged Na+ elevation, which in turn triggers Ca2+ influx via NCXs. This unique Ca2+ signaling pathway is further shown to be involved in the migration of NG2 cells. Thus, GABAergic signaling mediated by sequential activation of GABAA receptors, noninactivating Na+ channels, and NCXs may play an important role in the development and function of NG2 glial cells in the brain.

Guwiyang Wurra–‘Fire Mouse’: a global gene knockout model for TSPO/PBR drug development, loss-of-function and mechanisms of compensation studies

2015 ◽  
Vol 43 (4) ◽  
pp. 553-558 ◽  
Author(s):  
Ryan J. Middleton ◽  
Guo-Jun Liu ◽  
Richard B. Banati
Keyword(s):  
Mitochondrial Permeability Transition ◽  
Gene Knockout ◽  
Physiological Role ◽  
Permeability Transition Pore ◽  
Permeability Transition ◽  
Benzodiazepine Receptor ◽  
Translocator Protein ◽  
Loss Of Function ◽  
Recent Developments

The highly conserved 18-kDa translocator protein (TSPO) or peripheral benzodiazepine receptor (PBR), is being investigated as a diagnostic and therapeutic target for disease conditions ranging from inflammation to neurodegeneration and behavioural illnesses. Many functions have been attributed to TSPO/PBR including a role in the mitochondrial permeability transition pore (MPTP), steroidogenesis and energy metabolism. In this review, we detail the recent developments in determining the physiological role of TSPO/PBR, specifically based on data obtained from the recently generated Tspo knockout mouse models. In addition to defining the role of TSPO/PBR, we also describe the value of Tspo knockout mice in determining the selectivity, specificity and presence of any off-target effects of TSPO/PBR ligands.

scholarly journals Mice Deficient in the Axonemal Protein Tektin-t Exhibit Male Infertility and Immotile-Cilium Syndrome Due to Impaired Inner Arm Dynein Function

2004 ◽  
Vol 24 (18) ◽  
pp. 7958-7964 ◽  
Author(s):  
Hiromitsu Tanaka ◽  
Naoko Iguchi ◽  
Yoshiro Toyama ◽  
Kouichi Kitamura ◽  
Tohru Takahashi ◽  
...  
Keyword(s):  
Physiological Role ◽  
Electron Microscopic Examination ◽  
Electron Microscopic ◽  
Vitro Fertilization ◽  
Homozygous Mutant ◽  
Causal Genes ◽  
And Function ◽  
Ciliary Dyskinesia

ABSTRACT The haploid germ cell-specific Tektin-t protein is a member of the Tektin family of proteins that form filaments in flagellar, ciliary, and axonemal microtubules. To investigate the physiological role of Tektin-t, we generated mice with a mutation in the tektin-t gene. The homozygous mutant males were infertile, while the females were fully fertile. Sperm morphology and function were abnormal, with frequent bending of the sperm flagella and marked defects in motility. In vitro fertilization assays showed that the defective spermatozoa were able to fertilize eggs. Electron microscopic examination showed that the dynein inner arm structure was disrupted in the sperm flagella of tektin-t-deficient mice. Furthermore, homozygous mutant mice had functionally defective tracheal cilia, as evidenced by altered dynein arm morphology. These results indicate that Tektin-t participates in dynein inner arm formation or attachment and that the loss of Tektin-t results in impaired motility of both flagella and cilia. Therefore, the tektin-t gene is one of the causal genes for immotile-cilium syndrome/primary ciliary dyskinesia.

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