ABSTRACT
INTRODUCTION: This research evaluated the feasibility of a hybrid SSVEP + P300 brain computer interface (BCI) for controlling the movement of an avatar in a virtual reality (VR) gaming environment (VR + BCI). Existing VR + BCI gaming environments have limitations, such as visual fatigue, a lower communication rate, minimum accuracy, and poor system comfort. Hence, there is a need for an optimized hybrid BCI system that can simultaneously evoke the strongest P300 and SSVEP potentials in the cortex. METHODS: A BCI headset was coupled with a VR headset to generate a VR + BCI environment. The author developed a VR game in which the avatar's movement is controlled using the user's cortical responses with the help of a BCI headset. Specifically designed visual stimuli were used in the proposed system to elicit the strongest possible responses from the user's brain. The proposed system also includes an auditory feedback mechanism to facilitate precise avatar movement. RESULTS AND CONCLUSIONS: Conventional P300 BCI and SSVEP BCI were also used to control the movements of the avatar, and their performance metrics were compared to those of the proposed system. The results demonstrated that the hybrid SSVEP + P300 BCI system was superior to the other systems for controlling avatar movement.
Subject(s)
Avatar , Brain-Computer Interfaces , Electroencephalography , Event-Related Potentials, P300 , Video Games , Adult , Female , Humans , Male , Young Adult , Event-Related Potentials, P300/physiology , Movement/physiology , Psychomotor Performance/physiologyABSTRACT
INTRODUCTION: This study proposes a hybrid brain-computer interface (BCI) system that simultaneously evokes steady-state visual evoked potentials (SSVEP) and event-related potentials (P300). The goal of this study was to improve the performance of the current hybrid SSVEP + P300 BCI systems by incorporating inverted faces into visual stimuli. METHODS: In this study, upright and inverted faces were added to visual stimulus to elicit stronger cortical responses in a hybrid SSVEP + P300 BCI. We also considered triggering the P300 signals with facial stimuli and the SSVEP signals with non-facial stimuli. We have tested four paradigms: the upright face paradigm (UF), the inverted face paradigm (IF), the upright face and flicker paradigm (UFF), and the inverted face and flicker paradigm (IFF). RESULTS AND CONCLUSIONS: The results showed that the IFF paradigm evoked more robust cortical responses, which led to enhanced system accuracy and ITR. The IFF paradigm had an average accuracy of 96.6% and a system communication rate of 26.45 bits per second. The UFF paradigm is the best candidate for BCI applications among other paradigms because it provides maximum comfort while maintaining a reasonable ITR.
Subject(s)
Brain-Computer Interfaces , Electroencephalography , Event-Related Potentials, P300 , Evoked Potentials, Visual , Photic Stimulation , Humans , Evoked Potentials, Visual/physiology , Event-Related Potentials, P300/physiology , Male , Female , Photic Stimulation/methods , Electroencephalography/methods , Young Adult , Adult , Face , Pattern Recognition, Visual/physiology , Brain/physiologyABSTRACT
BACKGROUND: This study illustrates a hybrid brain-computer interface (BCI) in which steady-state visual evoked potentials (SSVEP) and event-related potentials (P300) are evoked simultaneously. The goal of this study was to improve the performance of the current hybrid SSVEP+P300 BCI systems by incorporating a happy face into visual stimuli. NEW METHOD: In this study, happy and sad faces were added to a visual stimulus to induce stronger cortical signals in a hybrid SSVEP+P300 BCI. Additionally, we developed a paradigm in which SSVEP responses were triggered by non-face stimuli, whereas P300 responses were triggered by face stimuli. We tested four paradigms: happy face paradigm (HF), sad face paradigm (SF), happy face and flicker paradigm (HFF), and sad face and flicker paradigm (SFF). RESULTS AND CONCLUSIONS: The results demonstrated that the HFF paradigm elicited more robust cortical responses, which resulted in enhanced system accuracy and information transfer rate (ITR). The HFF paradigm has a system communication rate of 25.9 bits per second and an average accuracy of 96.1%. Compared with other paradigms, the HFF paradigm is the best choice for BCI applications because it has the highest ITR and maximum level of comfort.
Subject(s)
Brain-Computer Interfaces , Electroencephalography , Event-Related Potentials, P300 , Evoked Potentials, Visual , Photic Stimulation , Humans , Evoked Potentials, Visual/physiology , Male , Event-Related Potentials, P300/physiology , Young Adult , Female , Electroencephalography/methods , Photic Stimulation/methods , Adult , Facial Expression , Brain/physiology , Facial Recognition/physiologyABSTRACT
The aim of the study was to examine the effects of repeated administrations of antioxidant multiminerals and vitamins in transition buffaloes on udder defense mechanism, antioxidant activity and occurrence of intramammary infection (IMI) in early lactation period. Forty clinically healthy pregnant buffaloes were enrolled 45 days before expected date of calving and randomly allocated into five different supplementation groups (n = 8): only basal ration (control), vitamin E and selenium (VES), multiminerals (MM), ascorbic acid (AA) and chromium (Cr) picolinate in basal diet. The udder defense mechanism was monitored by measuring phagocytic activity (PA), myeloperoxidase (MPO) and nitric oxide (NO) productions in milk leukocytes, antioxidant activity was evaluated by measuring total antioxidant capacity (TAC) in plasma and occurrence of IMI was assessed by milk cytology, bacterial count in milk and visible clinical signs of udder until day 28 post-calving. The results showed that the VES and MM supplementations exhibited significantly higher PA, MPO and NO productions of milk leukocytes till first week of lactation whereas, elevated mean TAC in plasma was maintained from day -7 to 1 of calving in MM supplementation group as compared to control group. Statistically, no significant difference in occurrences of subclinical or clinical IMI was noted across the groups until four weeks of lactation. Taken together, it is concluded that repeated administrations of VES and MM to transition buffaloes could be an effective strategy to maintain good udder health by augmenting milk leukocyte functions and antioxidant status and preventing incidence of IMI in early lactation.
Subject(s)
Antioxidants , Buffaloes , Dietary Supplements , Lactation , Mammary Glands, Animal , Vitamins , Animals , Female , Antioxidants/administration & dosage , Antioxidants/metabolism , Lactation/drug effects , Vitamins/administration & dosage , Vitamins/pharmacology , Mammary Glands, Animal/drug effects , Milk/chemistry , Diet/veterinary , Animal Feed/analysis , Minerals/administration & dosage , Pregnancy , Random AllocationABSTRACT
Phytopathogens cause plant diseases that threaten food security. Unlike mammals, plants lack an adaptive immune system and rely on their innate immune system to recognize and respond to pathogens. Plant response to a pathogen attack requires precise coordination of intracellular traffic and signaling. Spatial and/or temporal defects in coordinating signals and cargo can lead to detrimental effects on cell development. The role of intracellular traffic comes into a critical focus when the cell sustains biotic stress. In this review, we discuss the current understanding of the post-immune activation logistics of plant defense. Specifically, we focus on packaging and shipping of defense-related cargo, rerouting of intracellular traffic, the players enabling defense-related traffic, and pathogen-mediated subversion of these pathways. We highlight the roles of the cytoskeleton, cytoskeleton-organelle bridging proteins, and secretory vesicles in maintaining pathways of exocytic defense, acting as sentinels during pathogen attack, and the necessary elements for building the cell wall as a barrier to pathogens. We also identify points of convergence between mammalian and plant trafficking pathways during defense and highlight plant unique responses to illustrate evolutionary adaptations that plants have undergone to resist biotic stress.
Subject(s)
Immunity, Innate , Plants , Animals , Cytoskeleton/metabolism , Mammals , Organelles/metabolism , Plants/immunology , Plants/metabolism , Signal TransductionABSTRACT
Plant immunity depends on the secretion of antimicrobial proteins, which occurs through yet-largely unknown mechanisms. The trans-Golgi network (TGN), a hub for intracellular and extracellular trafficking pathways, and the cytoskeleton, which is required for antimicrobial protein secretion, are emerging as pathogen targets to dampen plant immunity. In this work, we demonstrate that tgnap1-2, a loss-of-function mutant of Arabidopsis TGNap1, a TGN-associated and microtubule (MT)-binding protein, is susceptible to Pseudomonas syringae (Pst DC3000). Pst DC3000 infected tgnap1-2 is capable of mobilizing defense pathways, accumulating salicylic acid (SA), and expressing antimicrobial proteins. The susceptibility of tgnap1-2 is due to a failure to efficiently transport antimicrobial proteins to the apoplast in a partially MT-dependent pathway but independent from SA and is additive to the pathogen-antagonizing MIN7, a TGN-associated ARF-GEF protein. Therefore, our data demonstrate that plant immunity relies on TGNap1 for secretion of antimicrobial proteins, and that TGNap1 is a key immunity element that functionally links secretion and cytoskeleton in SA-independent pathogen responses.
Subject(s)
Anti-Infective Agents , Arabidopsis Proteins , Arabidopsis , Carrier Proteins/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/metabolism , Arabidopsis/metabolism , Anti-Infective Agents/metabolism , Salicylic Acid/metabolism , Microtubules/metabolism , Pseudomonas syringae/physiology , Plant Diseases , Gene Expression Regulation, PlantABSTRACT
The plant cell boundary generally comprises constituents of the primary and secondary cell wall (CW) that are deposited sequentially during development. Although it is known that the CW acts as a barrier against phytopathogens and undergoes modifications to limit their invasion, the extent, sequence, and requirements of the pathogen-induced modifications of the CW components are still largely unknown, especially at the level of the polysaccharide fraction. To address this significant knowledge gap, we adopted the compatible Pseudomonas syringae-Arabidopsis thaliana system. We found that, despite systemic signaling actuation, Pseudomonas infection leads only to local CW modifications. Furthermore, by utilizing a combination of CW and immune signaling-deficient mutants infected with virulent or non-virulent bacteria, we demonstrated that the pathogen-induced changes in CW polysaccharides depend on the combination of pathogen virulence and the host's ability to mount an immune response. This results in a pathogen-driven accumulation of CW hexoses, such as galactose, and an immune signaling-dependent increase in CW pentoses, mainly arabinose, and xylose. Our analyses of CW changes during disease progression also revealed a distinct spatiotemporal pattern of arabinogalactan protein (AGP) deposition and significant modifications of rhamnogalacturonan sidechains. Furthermore, genetic analyses demonstrated a critical role of AGPs, specifically of the Arabinoxylan Pectin Arabinogalactan Protein1, in limiting pathogen growth. Collectively, our results provide evidence for the actuation of significant remodeling of CW polysaccharides in a compatible host-pathogen interaction, and, by identifying AGPs as critical elements of the CW in plant defense, they pinpoint opportunities to improve plants against diverse pathogens.
ABSTRACT
Plant phytohormone pathways are regulated by an intricate network of signaling components and modulators, many of which still remain unknown. Here, we report a forward chemical genetics approach for the identification of functional SA agonists in Arabidopsis thaliana that revealed Neratinib (Ner), a covalent pan-HER kinase inhibitor drug in humans, as a modulator of SA signaling. Instead of a protein kinase, chemoproteomics unveiled that Ner covalently modifies a surface-exposed cysteine residue of Arabidopsis epoxide hydrolase isoform 7 (AtEH7), thereby triggering its allosteric inhibition. Physiologically, the Ner application induces jasmonate metabolism in an AtEH7-dependent manner as an early response. In addition, it modulates PATHOGENESIS RELATED 1 (PR1) expression as a hallmark of SA signaling activation as a later effect. AtEH7, however, is not the exclusive target for this physiological readout induced by Ner. Although the underlying molecular mechanisms of AtEH7-dependent modulation of jasmonate signaling and Ner-induced PR1-dependent activation of SA signaling and thus defense response regulation remain unknown, our present work illustrates the powerful combination of forward chemical genetics and chemical proteomics for identifying novel phytohormone signaling modulatory factors. It also suggests that marginally explored metabolic enzymes such as epoxide hydrolases may have further physiological roles in modulating signaling.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Humans , Arabidopsis/metabolism , Plant Growth Regulators/metabolism , Epoxide Hydrolases/metabolism , Arabidopsis Proteins/metabolism , Salicylic Acid/metabolism , Gene Expression Regulation, PlantABSTRACT
Arabidopsis pathogen effector-triggered immunity (ETI) is controlled by a family of three lipase-like proteins (EDS1, PAD4, and SAG101) and two subfamilies of HET-S/LOB-B (HeLo)-domain "helper" nucleotide-binding/leucine-rich repeats (ADR1s and NRG1s). EDS1-PAD4 dimers cooperate with ADR1s, and EDS1-SAG101 dimers with NRG1s, in two separate defense-promoting modules. EDS1-PAD4-ADR1 and EDS1-SAG101-NRG1 complexes were detected in immune-activated leaf extracts but the molecular determinants for specific complex formation and function remain unknown. EDS1 signaling is mediated by a C-terminal EP domain (EPD) surface surrounding a cavity formed by the heterodimer. Here we investigated whether the EPDs of PAD4 and SAG101 contribute to EDS1 dimer functions. Using a structure-guided approach, we undertook a comprehensive mutational analysis of Arabidopsis PAD4. We identify two conserved residues (Arg314 and Lys380) lining the PAD4 EPD cavity that are essential for EDS1-PAD4-mediated pathogen resistance, but are dispensable for the PAD4-mediated restriction of green peach aphid infestation. Positionally equivalent Met304 and Arg373 at the SAG101 EPD cavity are required for EDS1-SAG101 promotion of ETI-related cell death. In a PAD4 and SAG101 interactome analysis of ETI-activated tissues, PAD4R314A and SAG101M304R EPD variants maintain interaction with EDS1 but lose association, respectively, with helper nucleotide-binding/leucine-rich repeats ADR1-L1 and NRG1.1, and other immune-related proteins. Our data reveal a fundamental contribution of similar but non-identical PAD4 and SAG101 EPD surfaces to specific EDS1 dimer protein interactions and pathogen immunity.
Subject(s)
Arabidopsis Proteins , Arabidopsis , Arabidopsis/metabolism , Arabidopsis Proteins/chemistry , Carboxylic Ester Hydrolases/genetics , Carboxylic Ester Hydrolases/metabolism , DNA-Binding Proteins/metabolism , Leucine/metabolism , Nucleotides/metabolism , Plant Diseases , Plant Immunity/geneticsABSTRACT
This study aims to extract cellulose nanofibers (CNFs) from a sustainable source, i.e. millet husk, which is an agro-waste worthy of consideration. Pre-treatments such as mercerisation, steam explosion, and peroxide bleaching (chlorine-free) were applied for the removal of non-cellulosic components. The bleached millet husk pulp was subjected to acid hydrolysis (5% oxalic acid) followed by homogenization to extract CNFs. The extracted CNFs were characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Dynamic Light Scattering (DLS), Energy Dispersive X-ray Spectroscopy (EDX), Thermogravimetry (TG and DTG), Differential scanning calorimetry (DSC), and Solid state 13C nuclear magnetic resonance spectroscopy (solid state 13C NMR). The isolated CNFs show a typical cellulose type-I structure with a diameter of 10-12 nm and a crystallinity index of 58.5%. The appearance of the specific peak at 89.31 ppm in the solid state 13C NMR spectra validates the existence of the type-I cellulose phase in the prepared CNFs. The prepared CNFs had a maximum degradation temperature (Tmax) of 341 °C, that was 31 °C greater than raw millet husk (RMH). The outcome of the study implies that the nanofibers are prominent alternatives for synthetic fibers for assorted potential applications, especially in manufacturing green composites.
Subject(s)
Nanofibers , Pennisetum , Cellulose/chemistry , Millets , Nanofibers/chemistry , Spectroscopy, Fourier Transform Infrared , ThermogravimetryABSTRACT
Wind turbines have been recognised as an alternative and clean-energy source with a low environmental impact. The selection of sites for wind-farm often creates serious conservation concerns on biodiversity. Wind turbines have become a serious threat to migratory birds as they collide with the turbine blades in some regions across the globe, while the impact on terrestrial mammals is relatively less explored. In this context, we assessed the responses of birds and mammals to the wind turbines in central Karnataka, India from January 2016 to May 2018 using carcass searches to quantify animal collisions (i.e., birds and bats), fixed radius point count for bird population parameters, and an occupancy framework for assessing the factor that determines the spatial occurrence of terrestrial mammals. The mean annual animal fatality rate per wind turbine was 0.26/year. Species richness, abundance, and unique species of birds were relatively higher in control sites over wind turbine sites. Species and functional compositions of birds in control sites were different from wind turbine sites, explaining the varied patterns of bird assemblages of different feeding guilds. Blackbuck, Chinkara, Golden Jackal, and Jungle Cat were less likely to occupy sites with a high number of wind turbines. The study indicates that certain bird and mammal species avoided wind turbine-dominated sites, affecting their distribution pattern. This is of concern to the management of the forested areas with wind turbines. We raised conservation issues and mitigating measures to overcome the negative effects of wind turbines on animals.
Subject(s)
Birds/physiology , Animals , Biodiversity , India , Power PlantsABSTRACT
Acquisition of nutrients from different species is necessary for pathogen colonization. Iron is an essential mineral nutrient for nearly all organisms, but little is known about how pathogens manipulate plant hosts to acquire iron. Here, we report that AvrRps4, an effector protein delivered by Pseudomonas syringae bacteria to plants, interacts with and targets the plant iron sensor protein BRUTUS (BTS) to facilitate iron uptake and pathogen proliferation in Arabidopsis thaliana. Infection of rps4 and eds1 by P. syringae pv. tomato (Pst) DC3000 expressing AvrRps4 resulted in iron accumulation, especially in the plant apoplast. AvrRps4 alleviates BTS-mediated degradation of bHLH115 and ILR3(IAA-Leucine resistant 3), two iron regulatory proteins. In addition, BTS is important for accumulating immune proteins Enhanced Disease Susceptibility1 (EDS1) at both the transcriptional and protein levels upon Pst (avrRps4) infections. Our findings suggest that AvrRps4 targets BTS to facilitate iron accumulation and BTS contributes to RPS4/EDS1-mediated immune responses.
Subject(s)
Arabidopsis Proteins/metabolism , Arabidopsis/physiology , Bacterial Proteins/metabolism , Host-Pathogen Interactions/physiology , Iron/metabolism , Ubiquitin-Protein Ligases/metabolism , Arabidopsis Proteins/genetics , Arabidopsis Proteins/immunology , Bacterial Proteins/genetics , Basic Helix-Loop-Helix Transcription Factors/metabolism , DNA-Binding Proteins/genetics , DNA-Binding Proteins/immunology , DNA-Binding Proteins/metabolism , Gene Expression Regulation, Plant , Mutation , Plant Immunity/genetics , Plants, Genetically Modified , Pseudomonas syringae/metabolism , Pseudomonas syringae/pathogenicity , Ubiquitin-Protein Ligases/geneticsABSTRACT
Neuroinflammation leads to neurodegeneration, cognitive defects, and neurodegenerative disorders. Neurotrauma/traumatic brain injury (TBI) can cause activation of glial cells, neurons, and neuroimmune cells in the brain to release neuroinflammatory mediators. Neurotrauma leads to immediate primary brain damage (direct damage), neuroinflammatory responses, neuroinflammation, and late secondary brain damage (indirect) through neuroinflammatory mechanism. Secondary brain damage leads to chronic inflammation and the onset and progression of neurodegenerative diseases. Currently, there are no effective and specific therapeutic options to treat these brain damages or neurodegenerative diseases. Flavone luteolin is an important natural polyphenol present in several plants that show anti-inflammatory, antioxidant, anticancer, cytoprotective, and macrophage polarization effects. In this short review article, we have reviewed the neuroprotective effects of luteolin in neurotrauma and neurodegenerative disorders and pathways involved in this mechanism. We have collected data for this study from publications in the PubMed using the keywords luteolin and mast cells, neuroinflammation, neurodegenerative diseases, and TBI. Recent reports suggest that luteolin suppresses systemic and neuroinflammatory responses in Coronavirus disease 2019 (COVID-19). Studies have shown that luteolin exhibits neuroprotective effects through various mechanisms, including suppressing immune cell activation, such as mast cells, and inflammatory mediators released from these cells. In addition, luteolin can suppress neuroinflammatory response, activation of microglia and astrocytes, oxidative stress, neuroinflammation, and the severity of neuroinflammatory diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, and TBI pathogenesis. In conclusion, luteolin can improve cognitive decline and enhance neuroprotection in neurodegenerative diseases, TBI, and stroke.
Subject(s)
Brain Injuries, Traumatic/drug therapy , COVID-19 Drug Treatment , Inflammation/drug therapy , Luteolin/therapeutic use , Neuroprotective Agents/therapeutic use , Brain/drug effects , Brain/virology , Brain Injuries/complications , Brain Injuries/drug therapy , Brain Injuries/virology , Brain Injuries, Traumatic/complications , Brain Injuries, Traumatic/virology , COVID-19/complications , COVID-19/virology , Flavones/therapeutic use , Humans , Inflammation/complications , Inflammation/virology , Neurons/drug effects , Neurons/virology , SARS-CoV-2/drug effects , SARS-CoV-2/pathogenicityABSTRACT
Pathogens attack plant cells to divert resources toward pathogen proliferation. To resist pathogens, plant cells rely on multilayered signaling pathways that hinge upon the secretory pathway for the synthesis and trafficking of pathogen sensors and defense molecules. In recent years, significant strides have been made in the understanding of the functional relationship between pathogen response and membrane traffic. Here we discuss how the plant cytoskeleton and endomembranes are targeted by pathogen effectors and highlight an emerging role of membrane contact sites in biotic stress responses.
Subject(s)
Plant Immunity , Plants , Cytoskeleton/metabolism , Microtubules , Protein TransportABSTRACT
An amendment to this paper has been published and can be accessed via a link at the top of the paper.
ABSTRACT
Mechanical interlocking of molecules (catenation) is a nontrivial challenge in modern synthetic chemistry and materials science1,2. One strategy to achieve catenation is the design of pre-annular molecules that are capable of both efficient cyclization and of pre-organizing another precursor to engage in subsequent interlocking3-9. This task is particularly difficult when the annular target is composed of a large ensemble of molecules, that is, when it is a supramolecular assembly. However, the construction of such unprecedented assemblies would enable the visualization of nontrivial nanotopologies through microscopy techniques, which would not only satisfy academic curiosity but also pave the way to the development of materials with nanotopology-derived properties. Here we report the synthesis of such a nanotopology using fibrous supramolecular assemblies with intrinsic curvature. Using a solvent-mixing strategy, we kinetically organized a molecule that can elongate into toroids with a radius of about 13 nanometres. Atomic force microscopy on the resulting nanoscale toroids revealed a high percentage of catenation, which is sufficient to yield 'nanolympiadane'10, a nanoscale catenane composed of five interlocked toroids. Spectroscopic and theoretical studies suggested that this unusually high degree of catenation stems from the secondary nucleation of the precursor molecules around the toroids. By modifying the self-assembly protocol to promote ring closure and secondary nucleation, a maximum catenation number of 22 was confirmed by atomic force microscopy.
ABSTRACT
Centrioles are cylindrical assemblies whose peripheral microtubule array displays a 9-fold rotational symmetry that is established by the scaffolding protein SAS6. Centriole symmetry can be broken by centriole-associated structures, such as the striated fibers in Chlamydomonas that are important for ciliary function. The conserved protein CCDC61/VFL3 is involved in this process, but its exact role is unclear. Here, we show that CCDC61 is a paralog of SAS6. Crystal structures of CCDC61 demonstrate that it contains two homodimerization interfaces that are similar to those found in SAS6, but result in the formation of linear filaments rather than rings. Furthermore, we show that CCDC61 binds microtubules and that residues involved in CCDC61 microtubule binding are important for ciliary function in Chlamydomonas. Together, our findings suggest that CCDC61 and SAS6 functionally diverged from a common ancestor while retaining the ability to scaffold the assembly of basal body-associated structures or centrioles, respectively.
Subject(s)
Cell Cycle Proteins/chemistry , Cell Cycle Proteins/metabolism , Chlamydomonas/physiology , Cilia/metabolism , Microtubule-Associated Proteins/chemistry , Microtubule-Associated Proteins/metabolism , Algal Proteins/chemistry , Algal Proteins/metabolism , Cell Line , Chlamydomonas/classification , Crystallography, X-Ray , HEK293 Cells , Humans , Microtubules/metabolism , Models, Molecular , Phylogeny , Protein Conformation , Protein Domains , Protein MultimerizationABSTRACT
PURPOSE: The aim of this study was to propose an index for evaluating dosimetric impact of inter-observer target delineation variability in brachytherapy. MATERIAL AND METHODS: The coverage with dosimetric concordance index (CDCI) is expressed as CDCIcommon and CDCIpair. The CDCIcommon is the mean coverage of target volume with common volume irradiated by prescription dose among all observers and represents the condition of worst target coverage. CDCIpair is the generalized form of CDCI, which is mean target coverage with common prescription volume obtained between all possible pairs of observers and represents more realistic coverage of target with dosimetric concordance. The index was used to evaluate the dosimetric impact of target delineation variability in optimized conformal plans on target volumes of five radiation oncologists for twenty patients of multi-catheter interstitial partial breast brachytherapy. RESULTS: The mean decline of 5.6 ±3.2% and 11.3 ±5.7% in CDCIpair and CDCIcommon, respectively, was observed comparing to coverage index (CI) of target volume in all patients due to inter-observer target variability. CDCIcommon and CDCIpair were found to have significant linear correlation (r = 0.964, p < 0.000). The difference between CDC and CI increased with the mean relative target volume among observers. Significant correlation (r = 0.962, p < 0.000) was also noted for the difference (Δ) in CDCIcommon and CDCIpair with CI of target volume. CONCLUSIONS: The recommended indices and difference between the dosimetric coverage of target volume (CI) with CDCI (ΔCDCI) can be used for evaluating dosimetric impact of the inter-observer target delineation variability.