Studies on hyphal development and appressorium formation of Colletotrichum graminicola

1978 ◽  
Vol 56 (18) ◽  
pp. 2234-2242 ◽  
Author(s):  
F. Kozar ◽  
Hans J. Netolitzky
Keyword(s):  
Germ Tube ◽  
Thick Wall ◽  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Reserve Material ◽  
Lipid Reserve ◽  
Mucilaginous Sheath ◽  
Stage Of Development ◽  
Definition Of ◽  
Cellular Organelles

The fine structure of actively growing hyphae of Colletotrichum graminicola was investigated. The hyphae were found to secrete a mucilaginous sheath into which melanizing particles and fibrils were deposited. Classical ubiquitous mitochondria, multipored doublewalled nuclei, ribosomes, mesosome-like structures, lomosomes, vacuoles, and inclusions such as lipids, closely associated with vacuoles, especially noticeable during germination, as well as glycogen were present. During maturation, vacuoles appeared and enlarged. In addition, a few endoplasmic reticulum profiles were observed in actively growing hyphae. Mitochondrial profiles changed from spherical to elongate. A plasmalemma, perhaps double in nature, was present. Penetration of one hypha by another was also observed.The mature appressorium exhibited a thick three-layered cell wall. This thick wall appeared to play a part in poor fixation and embedding, resulting in a poor definition of such cellular organelles as ribosomes, nuclei, etc. Internally, appressoria, depending on the stage of development, exhibited many vacuoles and osmiophilic deposits indicative of lipid reserve material. A germ pore through which a germ tube and migrating organelles and cytoplasm emerged was also observed.

Early interactions, adhesion, and establishment of the infection court by Erysiphe graminis

1995 ◽  
Vol 73 (S1) ◽  
pp. 609-615 ◽  
Author(s):  
Ralph L. Nicholson ◽  
Hitoshi Kunoh
Keyword(s):  
Hydrophobic Surface ◽  
Surface Hydrophobicity ◽  
Infection Process ◽  
Erysiphe Graminis ◽  
Hydrophilic Surface ◽  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Barley Leaf ◽  
Powdery Mildew Pathogen ◽  
Suitable Substratum

The establishment of a fungal pathogen on the surface of its host is essential to the success of the infection process. For many fungi, establishment on the host is an active process that may depend on recognition of the host surface through chemical or topographic signals. Events that allow for establishment may be considered to represent the "preparation of the infection court" by the pathogen. This sometimes involves the adhesion of the pathogen to the host and possibly the alteration of the host's surface topography or chemistry. Adhesion is often presumed to be a single, chemically mediated event associated with germ tube or appressorium formation. However, adhesion of ungerminated propagules may also occur, and evidence suggests that it is mediated by the release of adhesive materials directly from the propagule upon contact with a suitable substratum. Fungi may require either a hydrophobic or a hydrophilic surface to initiate the infection process. The barley powdery mildew pathogen, Erysiphe graminis, requires a hydrophilic surface for appressorium formation, yet the barley leaf is extremely hydrophobic. The problem is resolved by the release of an exudate from conidia that makes the hydrophobic leaf surface hydrophilic. In contrast, Colletotrichum graminicola requires a hydrophobic surface for the initiation of its infection process. Ungerminated conidia of this fungus release materials that allow for the rapid adhesion of conidia, which ensures that germination and appressorium formation occur, initiating the infection process. For both fungi, these events happen well in advance of germination and establish the pathogen at the site of the infection court. Key words: adhesion, cuticle, cutinase, surface hydrophobicity, infection process.

scholarly journals A Feed-Forward Subnetwork Emerging from Integrated TOR- and cAMP/PKA-Signaling Architecture Reinforces Magnaporthe oryzae Appressorium Morphogenesis

2019 ◽  
Vol 32 (5) ◽  
pp. 593-607 ◽  
Author(s):  
Guangchao Sun ◽  
Xiaobo Qi ◽  
Richard A. Wilson
Keyword(s):  
Cell Cycle ◽  
Adenylate Cyclase ◽  
Magnaporthe Oryzae ◽  
Environmental Conditions ◽  
Germ Tube ◽  
Nutrient Status ◽  
Specific Cell ◽  
Appressorium Formation ◽  
G2 Arrest ◽  
Feed Forward

Appressoria are important mediators of plant–microbe interactions. In the devastating rice blast pathogen Magnaporthe oryzae, appressorial morphogenesis from germ tube tips requires activated cAMP/PKA signaling and inactivated TOR signaling (TORoff). TORoff temporarily arrests G2 at a metabolic checkpoint during the single round of mitosis that occurs following germination. G2 arrest induces autophagy and appressorium formation concomitantly, allowing reprogression of the cell cycle to G1/G0 quiescence and a single appressorial nucleus. Inappropriate TOR activation abrogates G2 arrest and inhibits cAMP/PKA signaling downstream of cPKA. This results in multiple rounds of germ tube mitosis and the loss of autophagy and appressoria formation. How cAMP/PKA signaling connects to cell cycle progression and autophagy is not known. To address this, we interrogated TOR and cAMP/PKA pathways using signaling mutants, different surface properties, and specific cell cycle inhibitors and discovered a feed-forward subnetwork arising from TOR- and cAMP/PKA-signaling integration. This adenylate cyclase-cAMP-TOR-adenylate cyclase subnetwork reinforces cAMP/PKA-dependent appressorium formation under favorable environmental conditions. Under unfavorable conditions, the subnetwork collapses, resulting in reversible cell cycle-mediated germ tube growth regardless of external nutrient status. Collectively, this work provides new molecular insights on germ tube morphogenetic decision-making in response to static and dynamic environmental conditions.

scholarly journals RISK ECONOMY

2018 ◽  
pp. 16-55
Author(s):  
S. SOLODOVNICOV.
Keyword(s):  
High Tech ◽  
Negative Consequences ◽  
Theoretical Substantiation ◽  
Economic Concept ◽  
Stage Of Development ◽  
Global Catastrophe ◽  
Knowledge Intensive ◽  
Definition Of ◽  
Political Economic ◽  
Current Stage

The article is devoted to the theoretical substantiation of a new social paradigm – risk economy. The current stage of society development and the economy is characterized by a critical increase in financial, technological and technological, political and economic, geo-economic and other uncertainties. It is impossible to understand their ontological nature and reveal the phenomenological specificity without a meaningful definition of the current stage of development of the economic system of society. The article consistently revealed the characteristics of current society, which allowed the author to present a new political and economic concept that characterizes the current stage of development of society and the economy – the risk economy. The risk economy is an economy of high-tech and knowledge-intensive industries, characterized by the highest degree of political, economic, technological, financial and environmental uncertainties and risks. These risks are becoming comprehensive, many of them are in principle unpredictable, and their possible negative consequences could lead Humanity to a global catastrophe. Understanding the nature of risk economics is critically important for developing effective political and economic mechanisms to counter these risks.

scholarly journals Training of a future social professional for the formation of safe adolescent behavior in social networks

2021 ◽  
Keyword(s):  
Social Networks ◽  
Information Exchange ◽  
Professional Training ◽  
Social Groups ◽  
Real Life ◽  
Well Being ◽  
The Internet ◽  
Stage Of Development ◽  
Safe Behavior ◽  
Definition Of

The article analyzes different approaches to the definition of «social networks» as technological complexes of organization and management of electronic information exchange among the subjects of social relations, united by common interests, information needs and skills. Based on the analysis of the scientific literature the essential characteristics of social networks that affect the formation and development of the adolescent's personality are revealed. Role of social networks at the present stage of development of society, which is manifested in the representation of interests not only of social groups but also of entire social groups, is defined in the article. The negative impact of social networks on the personality of the adolescent, which is manifested in the expansion of adolescents in cyberspace, the desire for independence and adulthood, selfexperimentation, which leads to risky activities both on the Internet and in real life are revealed. Concept of safe behavior in social networks as a set of actions of the individual when using the Internet, helping to meet the needs and at the same time prevent the possibility of causing damage to physical, mental, social well-being and property of man and others is analyzed. The basic rules of safe behavior in social Internet communities are highlighted. The structural components of safe behavior of adolescents in social networks are singled out: cognitive, motivational and actionreflexive; the concept of «professional training of future social professionals for the formation of safe behavior of adolescents in social networks» is revealed. Readiness is revealed as a result of the process of training future social specialists for professional activity on the formation of safe behavior of adolescents in social networks; the author's definition of the concept «readiness of future social professionals to form safe behavior of adolescents in social networks» is given. Components of readiness of future social workers to form safe behavior of teenagers in social networks, such as cognitive, motivational-personal and activity, are described.

History of HgTe-based photodetectors in Poland

2010 ◽  
Vol 18 (3) ◽  
Author(s):  
A. Rogalski
Keyword(s):  
High Performance ◽  
Flicker Noise ◽  
Vapour Phase ◽  
Fast Response ◽  
Thick Wall ◽  
Vapour Phase Epitaxy ◽  
Stage Of Development ◽  
In Series ◽  
Multiple Cell ◽  
And Performance

AbstractIn Poland, the HgCdTe studies began in 1960 at the Institute of Physics, Warsaw University. The material processing laboratory was created by Giriat and later by Dziuba, Gałązka, and others. Bridgman technique with sealed thick wall quartz ampoules was used to grow material suitable for research and experimental devices. Among the first papers published in 1961 and 1963 there were the Polish works devoted to preparation, doping, and electrical properties of HgCdTe.Infrared detector’s research and development efforts in Poland were concentrated mostly on uncooled market niche. At the beginning, a modified isothermal vapour phase epitaxy has been used for research and commercial fabrication of photoconductive, photoelectromagnetic and other HgCdTe devices. Bulk growth and liquid phase epitaxy were also used. Recently, the fabrication of infrared devices relies on low temperature epitaxial technique, namely metalorganic vapour phase deposition.At present stage of development, the photoconductive and photoelectromagnetic (PEM) detectors are gradually replaced with photovoltaic devices which offer inherent advantages of no electric or magnetic bias, no heat load and no flicker noise. Potentially, photodiodes offer high performance and very fast response. However, conventional photovoltaic uncooled detectors suffer from low quantum efficiency and very low junction resistance. The problems have been solved with advanced band gap engineered architecture, multiple cell heterojunction devices connected in series, and monolithic integration of the detectors with microoptics.In final part of the paper, the Polish achievements in technology and performance of HgMnTe and HgZnTe photodetectors are presented.

F-actin localization dynamics during appressorium formation in Colletotrichum graminicola

Mycologia ◽  
2016 ◽  
Vol 108 (3) ◽  
pp. 506-514 ◽  
Author(s):  
Chih-Li Wang ◽  
Brian D. Shaw
Keyword(s):  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Actin Localization

scholarly journals Bypassing Both Surface Attachment and Surface Recognition Requirements for Appressorium Formation by Overactive Ras Signaling in Magnaporthe oryzae

2014 ◽  
Vol 27 (9) ◽  
pp. 996-1004 ◽  
Author(s):  
Xiaoying Zhou ◽  
Xinhua Zhao ◽  
Chaoyang Xue ◽  
Yafeng Dai ◽  
Jin-Rong Xu
Keyword(s):  
Magnaporthe Oryzae ◽  
Pathogenic Fungi ◽  
Mitogen Activated Protein Kinase ◽  
Ras Signaling ◽  
Colletotrichum Graminicola ◽  
Appressorium Formation ◽  
Surface Attachment ◽  
Surface Recognition ◽  
Aerial Hyphae ◽  
Liquid Suspensions

Magnaporthe oryzae forms a highly specialized infection structure called an appressorium for plant penetration. In M. oryzae and many other plant-pathogenic fungi, surface attachment and surface recognition are two essential requirements for appressorium formation. Development of appressoria in the air has not been reported. In this study, we found that expression of a dominant active MoRAS2G18V allele in M. oryzae resulted in the formation of morphologically abnormal appressoria on nonconducive surfaces, in liquid suspensions, and on aerial hyphae without attachment to hard surfaces. Both the Pmk1 mitogen-activated protein kinase cascade and cAMP signaling pathways that regulate surface recognition and appressorium morphogenesis in M. oryzae were overactivated in the MoRAS2G18V transformant. In mutants deleted of PMK1 or CPKA, expression of MoRAS2G18V had no significant effects on appressorium morphogenesis. Furthermore, expression of dominant MoRAS2 in Colletotrichum graminicola and C. gloeosporioides also caused the formation of appressorium-like structures in aerial hyphae. Overall, our data indicate that MoRas2 functions upstream from both the cAMP-PKA and Pmk1 pathways and overactive Ras signaling leads to improper activation of these two pathways and appressorium formation without surface attachment in appressorium-forming pathogens.

Effects of temperature and antibiotics on appressorium formation in spores of Colletotrichum lagenarium

1977 ◽  
Vol 23 (5) ◽  
pp. 626-629 ◽  
Author(s):  
Machiko Tani ◽  
Norio Ishida ◽  
Iwao Furusawa
Keyword(s):  
Spore Germination ◽  
Germ Tube ◽  
Temperature Treatment ◽  
Appressorium Formation ◽  
Colletotrichum Lagenarium ◽  
Effects Of Temperature ◽  
Blasticidin S

Effects of temperature (32 °C), cycloheximide, and blasticidin-S on spore germination and appressorium formation of Colletotrichum lagenarium were investigated. Temperature treatment at 32 °C, given just before the emergence of the germ tube 4 h after incubation at 24 °C, significantly inhibited appressorium formation. Cycloheximide (1 ppm) or blasticidin-S (7 ppm) appeared to have reversed the effect of 32 °C treatment by producing appressoria in 30% of the germinated spores.

scholarly journals THEORETICAL AND LEGAL ASPECT OF THE FORMATION OF THE INSTITUTE OF ACCESSORY OBLIGATIONS.

2021 ◽  
Vol 2 (67) ◽  
pp. 68-72
Author(s):  
R. Truhan ◽  
S Nadtochij
Keyword(s):  
Legal Aspect ◽  
Civil Law ◽  
Roman Law ◽  
Soviet Period ◽  
Legal Doctrine ◽  
Stage Of Development ◽  
Legal Relationship ◽  
Characteristic Features ◽  
Definition Of ◽  
Further Development

The subject of the article is the study of the theoretical and legal aspect of the development of the institution of accessory obligations. The genesis of the category of "accessory" in Roman law is considered, where the formula of the ancients is derived: the validity of the accessory legal relationship is predetermined by the reality of the basic legal relationship, and was quite simple and concise, there is no basic obligation - no additional one. The evolution of "accessory" in domestic civil law is revealed, which consists in the following: in pre-revolutionary civil law, the theory of security deviated from accessory for the sake of convenience for the circulation of security obligations; in the Soviet period, the identification of the terms "security" and "accessory" obligation took root in the scientific circulation; and at the present stage of development of the theory of accessory in Russian civil law, the concept of "accessory" is identified with a security obligation.The author comes to the conclusion about the multidimensionality of the category of "accessory", which consists in the fact that in the course of the development of law, the understanding of accessory obligations has undergone significant changes, going from the perception of accessory as a kind of obligation that ensures the return of debt and the transfer of "belonging" to the goods sold, to its identification with security obligations in general. Gradually, in the legal doctrine, the opinion was fixed that different types of obligations have the property of accessory, and each of them has its own characteristic features and has its own specifics. According to the authors of the article, the further development of the civilistic doctrine of the accessory of obligations will contribute to the final consolidation of the definition of "accessory" within the framework of Russian civil law.

scholarly journals Types of Human Health

2020 ◽  
Vol 3 (18) ◽  
pp. 43-48
Author(s):  
Līga Mazure
Keyword(s):  
Human Health ◽  
Legal Definition ◽  
Stage Of Development ◽  
Definition Of Health ◽  
Definition Of

WHO has significantly contributed to the modern legal definition of human health by providing a definition of health. This definition of health acquired a binding nature, becoming the content of national rules and regulations. WHO’s definition of health indirectly covers the types of human health. Although this definition of health was appraised as an innovative view of the understanding of human health, still nowadays it does not correspond to the stage of development of society. Nowadays it is an expansion of the understanding of health as a nonmaterial good. A more detailed system of the types of human health can be created and legally recorded according to several division criteria. PVO ir devusi būtisku ieguldījumu cilvēka veselības tiesiskā definējuma formulēšanā, dodot veselības skaidrojumu. PVO veselības definējumā netieši ir ietverti arī cilvēka veselības veidi. Šis veselības definējums ir ieguvis saistošo raksturu, kļūstot par valstu normatīvā regulējuma saturu. Lai arī šis veselības definējums savulaik bija vērtējams kā inovatīvs skatījums uz cilvēka veselības izpratni, tomēr tas vairs neatbilst mūsdienu sabiedrības attīstības pakāpei. Ir notikusi veselības kā nemantiskā labuma izpratnes paplašināšanās, tāpēc būtu jāizveido un tiesiski jānostiprina detalizētāka cilvēka veselības veidu sistēma pēc dažādiem dalījuma kritērijiem. Lai normatīvajā regulējumā varētu iestrādāt piedāvātās idejas, ir nepieciešams papildināt Ārstniecības likumu ar 31. pantu šādā redakcijā: “31. pants. (1) Pacients tiek uzskatīts par pilnīgi veselu līdz brīdim, kad tiek konstatēts viņa faktiskais veselības stāvoklis un tā turpmākā attīstība ir paredzama. (2) Pacienta atgriezeniskā veselība nozīmē, ka pastāv iespēja mazināt vai novērst veselības traucējumus; turpretim neatgriezeniskā veselība nozīmē, ka veselības stāvoklis ir nemainīgs vai tas pasliktinās. (3) Pacienta veselība var būt nemainīga vai augšupejoša, ja tā uzlabojas, vai lejupejoša, ja pasliktinās. (4) Pacientam pēc dzimšanas konstatētais veselības stāvoklis ir viņam sākotnēji piemītošā veselība. Pacients var uzlabot to, mazinot vai novēršot pēc dzimšanas konstatētos veselības traucējumus, kā arī atjaunot to, mazinot vai novēršot dzīves laikā iegūtos veselības traucējumus. (5) Ar pacienta iekšējo veselību saprot viņa ķermeniskās un garīgās spējas, turpretim ar ārējo veselību – spēju socializēties un gūt personīgo piepildījumu.”

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