scholarly journals CfLec-3 from scallop: an entrance to non-self recognition mechanism of invertebrate C-type lectin

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Jialong Yang ◽  
Mengmeng Huang ◽  
Huan Zhang ◽  
Lingling Wang ◽  
Hao Wang ◽  
...  
Keyword(s):  
Recognition Mechanism ◽  
Self Recognition

Small peptide–mediated self-recognition prevents cannibalism in predatory nematodes

Science ◽  
2019 ◽  
Vol 364 (6435) ◽  
pp. 86-89 ◽  
Author(s):  
James W. Lightfoot ◽  
Martin Wilecki ◽  
Christian Rödelsperger ◽  
Eduardo Moreno ◽  
Vladislav Susoy ◽  
...  
Keyword(s):  
Hypervariable Region ◽  
Recognition System ◽  
Natural World ◽  
Single Amino Acid ◽  
Biological Processes ◽  
Small Peptide ◽  
Recognition Mechanism ◽  
Self Recognition ◽  
C Terminus ◽  
Molecular Machinery

Self-recognition is observed abundantly throughout the natural world, regulating diverse biological processes. Although ubiquitous, often little is known of the associated molecular machinery, and so far, organismal self-recognition has never been described in nematodes. We investigated the predatory nematode Pristionchus pacificus and, through interactions with its prey, revealed a self-recognition mechanism acting on the nematode surface, capable of distinguishing self-progeny from closely related strains. We identified the small peptide SELF-1, which is composed of an invariant domain and a hypervariable C terminus, as a key component of self-recognition. Modifications to the hypervariable region, including single–amino acid substitutions, are sufficient to eliminate self-recognition. Thus, the P. pacificus self-recognition system enables this nematode to avoid cannibalism while promoting the killing of competing nematodes.

scholarly journals Self-Recognition Mechanism between Skin and Suckers Prevents Octopus Arms from Interfering with Each Other

2014 ◽  
Vol 24 (11) ◽  
pp. 1271-1275 ◽  
Author(s):  
Nir Nesher ◽  
Guy Levy ◽  
Frank W. Grasso ◽  
Binyamin Hochner
Keyword(s):  
Recognition Mechanism ◽  
Self Recognition

A Study of Method on Evaluation of Aircraft's IR Image Stealth Effectiveness

2014 ◽  
Vol 926-930 ◽  
pp. 1651-1655
Author(s):  
Shi Jie Chai ◽  
Zhong Xiang Tong ◽  
Chao Zhe Wang
Keyword(s):  
Computer Simulation ◽  
Target Tracking ◽  
Ir Detectors ◽  
Detector Performance ◽  
Recognition Mechanism ◽  
Evaluation Indexes ◽  
Self Recognition ◽  
Validation Experiment ◽  
Current Assessment

Drawing up evaluation indexes is key of Evaluation of aircrafts IR stealth effectiveness. To solve the problem of high costs and great difficulties in indexs validation experiment, this paper was using method of computer simulation to obtain images and computer judging to evaluating quantitatively of Aircrafts stealth effectiveness. Closely integrating with IR detectors recognition mechanism, the evaluation indexes were determined that can assess IR stealth effectiveness quantitatively when aircraft adopts different stealth technics, different interference measures, and confronts different IR detectors. These evaluation indexes overcome the shortcomings in current assessment, such as impacted greater by detector performance, can not reflect active IR stealths action, e.g. IR decoys interference, and deviate large from IR detectors self-recognition and target tracking result.

scholarly journals Self-recognition mechanism of MamA, a magnetosome-associated TPR-containing protein, promotes complex assembly

2011 ◽  
Vol 108 (33) ◽  
pp. E480-E487 ◽  
Author(s):  
N. Zeytuni ◽  
E. Ozyamak ◽  
K. Ben-Harush ◽  
G. Davidov ◽  
M. Levin ◽  
...  
Keyword(s):  
Recognition Mechanism ◽  
Complex Assembly ◽  
Self Recognition

scholarly journals PAPC mediates self/non–self-distinction during Snail1-dependent tissue separation

2015 ◽  
Vol 208 (6) ◽  
pp. 839-856 ◽  
Author(s):  
Olivia Luu ◽  
Erich W. Damm ◽  
Serge E. Parent ◽  
Debanjan Barua ◽  
Tamara H.L. Smith ◽  
...  
Keyword(s):  
Cell Sorting ◽  
Planar Cell Polarity ◽  
Adherens Junction ◽  
Distinct Type ◽  
Adhesive Contact ◽  
Cell Level ◽  
Recognition Mechanism ◽  
Tissue Separation ◽  
Self Recognition ◽  
Cleft Formation

Cleft-like boundaries represent a type of cell sorting boundary characterized by the presence of a physical gap between tissues. We studied the cleft-like ectoderm–mesoderm boundary in Xenopus laevis and zebrafish gastrulae. We identified the transcription factor Snail1 as being essential for tissue separation, showed that its expression in the mesoderm depends on noncanonical Wnt signaling, and demonstrated that it enables paraxial protocadherin (PAPC) to promote tissue separation through two novel functions. First, PAPC attenuates planar cell polarity signaling at the ectoderm–mesoderm boundary to lower cell adhesion and facilitate cleft formation. Second, PAPC controls formation of a distinct type of adhesive contact between mesoderm and ectoderm cells that shows properties of a cleft-like boundary at the single-cell level. It consists of short stretches of adherens junction–like contacts inserted between intermediate-sized contacts and large intercellular gaps. These roles of PAPC constitute a self/non–self-recognition mechanism that determines the site of boundary formation at the interface between PAPC-expressing and -nonexpressing cells.

scholarly journals Evolutionary pathways for the generation of new self-incompatibility haplotypes in a non-self recognition system

2018 ◽  
Author(s):  
Katarína Bod’bvá ◽  
Tadeas Priklopil ◽  
David L. Field ◽  
Nicholas H. Barton ◽  
Melinda Pickup
Keyword(s):  
Genetic Model ◽  
Haplotype Diversity ◽  
Recognition System ◽  
Stochastic Simulations ◽  
Self Incompatibility ◽  
Recognition Mechanism ◽  
Evolutionary Pathway ◽  
Self Pollination ◽  
Self Recognition ◽  
Evolutionary Pathways

AbstractSelf-incompatibility (SI) is a genetically based recognition system that functions to prevent self-fertilization and mating among related plants. An enduring puzzle in SI is how the high diversity observed in nature arises and is maintained. Based on the underlying recognition mechanism, SI can be classified into two main groups: self- and non-self recognition. Most work has focused on diversification within self-recognition systems despite expected differences between the two groups in the evolutionary pathways and outcomes of diversification. Here, we use a deterministic population genetic model and stochastic simulations to investigate how novel S-haplotypes evolve in a gametophytic non-self recognition (SRNase/S Locus F-box (SLF)) SI system. For this model the pathways for diversification involve either the maintenance or breakdown of SI and can vary in the order of mutations of the female (SRNase) and male (SLF) components. We show analytically that diversification can occur with high inbreeding depression and self-pollination, but this varies with evolutionary pathway and level of completeness (which determines the number of potential mating partners in the population), and in general is more likely for lower haplotype number. The conditions for diversification are broader in stochastic simulations of finite population size. However, the number of haplotypes observed under high inbreeding and moderate to high self-pollination is less than that commonly observed in nature. Diversification was observed through pathways that maintain SI as well as through self-compatible intermediates. Yet the lifespan of diversified haplotypes was sensitive to their level of completeness. By examining diversification in a non-self recognition SI system, this model extends our understanding of the evolution and maintenance of haplotype diversity observed in a recognition system common in flowering plants.

scholarly journals EXPERIMENTAL IMMUNOLOGIC ADRENAL INJURY

1960 ◽  
Vol 112 (1) ◽  
pp. 187-202 ◽  
Author(s):  
Jan W. Steiner ◽  
B. Langer ◽  
D. L. Schatz ◽  
R. Volpe
Keyword(s):  
Cellular Response ◽  
Inhibitory Effect ◽  
Outer Cortex ◽  
Cortical Cells ◽  
Recognition Mechanism ◽  
Defensive Reaction ◽  
Self Recognition ◽  
Tissue Homogenates ◽  
Freund’S Adjuvant ◽  
Freund's Adjuvant

Twenty-three unilaterally adrenalectomized guinea pigs were injected with autologous and homologous adrenal tissue homogenates respectively, in Freund's adjuvant. Widespread adrenal lesions were found in 10 of 12 animals receiving auto-antigen and to a lesser extent in 6 of 11 animals injected with homologous pooled antigen. Widespread systemic lesions were present in both these and in control animals receiving Freund's adjuvant alone. These latter animals showed no adrenal involvement. The early changes within the adrenal consisted of perisinusoidal cellular proliferations in the deeper layers of the cortex. Focal granulomata developing at a later stage tended to become confluent and to displace cortical cells. Some loss of these cells was attributable to ischemic injury. The localization in the deep fasciculata and reticularis was thought to depend (a) on the varying antigenicity of adrenal cortical components, (b) the possible inhibitory effect of antiphlogistic adrenal cortical hormones on the development of lesions in the outer cortex, and (c) the presence of littoral cells in the deep cortex. These cells are thought to be involved in the mediation of the stimulus initiating differentiation of primitive mesenchymal cells in response to a circulating auto-antigen. The medullary lesions may be related to the presence of ectopic reticularis cells in this location. It was suggested that the cellular response in the target organ to injections of adrenal homogenates may denote a specific "organ-self" recognition mechanism involving an immune (i.e. defensive) reaction. It was postulated that this may be an accentuation of the physiological function of immunologically competent cells. Their proliferation, under normal circumstances, would prevent by means of production of "binding" globulins, the escape and dissemination of endogenous freed adrenal antigens into the circulation. Although the experimental stimulus arose from without the gland, by virtue of the presence of a circulating adjuvant-bound antigen, the adrenal reaction followed the same pattern as would obtain if the antigen was liberated within the suprarenal cortex.

scholarly journals Diversification or collapse of self-incompatibility haplotypes as a rescue process

2020 ◽  
Author(s):  
Alexander Harkness ◽  
Emma E. Goldberg ◽  
Yaniv Brandvain
Keyword(s):  
Gene Conversion ◽  
Conversion Rate ◽  
Markov Chain Model ◽  
The Self ◽  
Allelic Polymorphism ◽  
Chain Model ◽  
Self Incompatibility ◽  
Recognition Mechanism ◽  
Self Recognition ◽  
Incompatibility Locus

AbstractIn angiosperm self-incompatibility systems, pollen with an allele matching the pollen recipient at the self-incompatibility locus is rejected. Extreme allelic polymorphism is maintained by frequency-dependent selection favoring rare alleles. However, two challenges limit the spread of a new allele (a tightly linked haplotype in this case) under the widespread “collaborative non-self recognition” mechanism. First, there is no obvious selective benefit for pollen compatible with non-existent stylar incompatibilities, which themselves cannot spread if no pollen can fertilize them. However, a pistil-function mutation complementary to a previously neutral pollen mutation may spread if it restores self-incompatibility to a self-compatible intermediate. Second, we show that novel haplotypes can drive elimination of existing ones with fewer siring opportunities. We calculate relative probabilities of increase and collapse in haplotype number given the initial collection of incompatibility haplotypes and the population gene conversion rate. Expansion in haplotype number is possible when population gene conversion rate is large, but large contractions are likely otherwise. A Markov chain model derived from these expansion and collapse probabilities generates a stable haplotype number distribution in the realistic range of 10–40 under plausible parameters. However, smaller populations might lose many haplotypes beyond those lost by chance during bottlenecks.

scholarly journals SPWD Based IEEE 1451.2 Smart Sensor Self-Recognition Mechanism and Realization

2012 ◽  
Vol 29 ◽  
pp. 2501-2505 ◽  
Author(s):  
Guixiong Liu ◽  
Gengxin Chen ◽  
Yuebin Zhou
Keyword(s):  
Smart Sensor ◽  
Recognition Mechanism ◽  
Self Recognition

scholarly journals The basic building blocks and evolution of CRISPR–Cas systems

2013 ◽  
Vol 41 (6) ◽  
pp. 1392-1400 ◽  
Author(s):  
Kira S. Makarova ◽  
Yuri I. Wolf ◽  
Eugene V. Koonin
Keyword(s):  
Adaptive Immunity ◽  
Purifying Selection ◽  
Building Blocks ◽  
Comparative Sequence Analysis ◽  
Structural Rearrangements ◽  
Recognition Mechanism ◽  
Recent Advances ◽  
Self Recognition ◽  
First Time ◽  
Cas Proteins

CRISPR (clustered regularly interspaced short palindromic repeats)–Cas (CRISPR-associated) is an adaptive immunity system in bacteria and archaea that functions via a distinct self/non-self recognition mechanism that involves unique spacers homologous with viral or plasmid DNA and integrated into the CRISPR loci. Most of the Cas proteins evolve under relaxed purifying selection and some underwent dramatic structural rearrangements during evolution. In many cases, CRISPR–Cas system components are replaced either by homologous or by analogous proteins or domains in some bacterial and archaeal lineages. However, recent advances in comparative sequence analysis, structural studies and experimental data suggest that, despite this remarkable evolutionary plasticity, all CRISPR–Cas systems employ the same architectural and functional principles, and given the conservation of the principal building blocks, share a common ancestry. We review recent advances in the understanding of the evolution and organization of CRISPR–Cas systems. Among other developments, we describe for the first time a group of archaeal cas1 gene homologues that are not associated with CRISPR–Cas loci and are predicted to be involved in functions other than adaptive immunity.

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