Obligate parasites of nematodes: viruses and bacteria in the genus Pasteuria.

2014 ◽  
pp. 193-222
Author(s):  
G. R. Stirling
Keyword(s):  
Obligate Parasites

scholarly journals Parasite co-opts a ubiquitin receptor to induce a plethora of developmental changes

2021 ◽  
Author(s):  
Weijie Huang ◽  
Allyson M. MacLean ◽  
Akiko Sugio ◽  
Abbas Maqbool ◽  
Marco Busscher ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Substitution ◽  
Trophic Levels ◽  
Developmental Changes ◽  
Effector Protein ◽  
Insect Vector ◽  
Developmental Processes ◽  
Phenotypic Changes ◽  
Obligate Parasites ◽  
Functional Variant

AbstractObligate parasites can induce complex and substantial phenotypic changes in their hosts in ways that favour their transmission to other trophic levels. However, mechanisms underlying these changes remain largely unknown. Here, we demonstrate how SAP05 protein effectors from insect-vectored plant pathogenic phytoplasmas take control of several plant developmental processes to simultaneously prolong host lifespan and induce witch’s broom-like proliferations of leaf and sterile shoots, organs colonized by phytoplasmas and vectors. SAP05 acts by mediating the concurrent degradation of SPL and GATA developmental regulators via a process that uniquely relies on hijacking the plant ubiquitin receptor RPN10 independently of substrate lysine ubiquitination. RPN10 is highly conserved among eukaryotes, but SAP05 does not bind insect vector RPN10. A two-amino-acid substitution within plant RPN10 generates a functional variant that is resistant to SAP05 activities. Therefore, one effector protein enables obligate parasitic phytoplasmas to induce a plethora of developmental phenotypes in their hosts.

scholarly journals The most frequent 'rusts' on trees and shrubs in Serbia

2003 ◽  
pp. 77-101 ◽  
Author(s):  
Dragan Karadzic ◽  
Tanja Milijasevic
Keyword(s):  
Cultivated Plants ◽  
Economic Significance ◽  
Obligate Parasites ◽  
First Time ◽  
Trees And Shrubs

This paper describes 15 species of fungi in the order Uredinales, causing the diseases known as "rusts". These fungi develop as obligate parasites and cause very dangerous diseases on cultivated plants. Among the "rusts" occurring on the trees, the following rusts are of special economic significance Melampsorella caryophyllacearum (rust on fir), Cronartium flaccidum (rust on two-needle pines) and Melampsora species (rusts on poplars). Fungi Chrysomyxa pirolata, Pucciniastrum epilobii, Gymnosporangium clavariiforme and G. tremelloides have been identified for the first time in Serbia.

scholarly journals The saga of scrub typhus with a note on the outbreaks in Mizoram

2018 ◽  
Vol 18 (2) ◽  
pp. 50-57
Author(s):  
K. Lalchhandama
Keyword(s):  
Infectious Disease ◽  
Opportunistic Infection ◽  
Scrub Typhus ◽  
Emerging Infectious Disease ◽  
Human Infection ◽  
Bacterial Disease ◽  
Orientia Tsutsugamushi ◽  
Obligate Parasites ◽  
Serious Disease ◽  
Collective Information

Scrub typhus is one the most important re-emerging infectious disease, and perhaps, the most important bacterial disease. Caused by Orientia tsutsugamushi, it is transmitted through the bite of mites belonging to the genus Leptotrombidium, in which the bacteria are obligate parasites. Though the mites are natural ectoparasites of rodents and other animals, in which there is no disease, opportunistic infection to humans gives rise to a serious disease. Known to Japanese physicians as tsutsugamushi (insect disease), human infection is caused by the larvae of trombiculid mites, the fact established by Mataro Nagayo and co-workers established in 1917. The pathogen was discovered by Naosuke Hayashi in 1920. In Mizoram, the disease has been rampant since 2011. This paper summarises available data on the prevalence of the infection in different districts base on collective information from various sources. Records between 2012 and 2018 show that over a thousand people had been infected and 35 people had died of the disease.

1. What are viruses?

2018 ◽  
pp. 2-16
Author(s):  
Dorothy H. Crawford
Keyword(s):  
Electron Microscope ◽  
Mutation Rate ◽  
Molecular Clock ◽  
Antiviral Drugs ◽  
High Mutation Rate ◽  
Virus Identification ◽  
Obligate Parasites ◽  
Protein Coat ◽  
A Cell

‘What are viruses?’ introduces viruses and their structure. Martinus Beijerinck, in 1898, was the first to coin the term ‘virus’, and invention of the electron microscope in the late 1930s greatly enhanced virus identification. Viruses are not cells, but obligate parasites that must infect a cell and use its organelles in order to reproduce. They carry either DNA or RNA, and have a protein coat called a capsid. The whole structure is called a virion. Viruses have a high mutation rate, which helps them to survive and boost their resistance to antiviral drugs. The molecular clock technique to track a virus’s history is also explained.

Pentastomiasis (porocephalosis, linguatulosis/linguatuliasis, or tongue worm infection)

2020 ◽  
pp. 1582-1586
Author(s):  
David A. Warrell
Keyword(s):  
Intermediate Hosts ◽  
Internal Organs ◽  
Obligate Parasites ◽  
Living Species ◽  
Vertebrate Hosts ◽  
Upper Respiratory

Pentastomida are dioecious, obligate parasites that are currently grouped in subclass Branchiura (fish lice and cycloids) of class Maxillopoda, subphylum Crustacea, phylum Arthropoda. Common names are ‘pentastomes’ (referring to two pairs of hooks above the mouth that give the impression of five stomata) or ‘tongue worms’ (alluding to the tongue-like appearance of some, such as adult Linguatula). Adult pentastomes inhabit the upper respiratory tracts of their end hosts (vertebrates such as reptiles, fish, birds, and mammals) where they feed on blood and other tissues. Their larvae infect internal organs of vertebrate or arthropod intermediate hosts. Pentastomes appear to have coevolved with other maxillopodan/branchiuran parasites and their vertebrate hosts. There are about 100 living species in the orders Cephalobaenida (e.g. genus Raillietiella) and Porocephalida (e.g. genera Linguatula, Armillifer, Porocephalus, Leiperia, and Sebekia).

scholarly journals Catalase and Ascorbate Peroxidase in Euglenozoan Protists

Pathogens ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 317 ◽  
Author(s):  
Ingrid Škodová-Sveráková ◽  
Kristína Záhonová ◽  
Barbora Bučková ◽  
Zoltán Füssy ◽  
Vyacheslav Yurchenko ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Ascorbate Peroxidase ◽  
Biochemical Properties ◽  
Heterotrophic Flagellates ◽  
Oxygen Species ◽  
Detoxifying Enzymes ◽  
Free Living ◽  
Present Evidence ◽  
Obligate Parasites ◽  
Membrane Bound

In this work, we studied the biochemical properties and evolutionary histories of catalase (CAT) and ascorbate peroxidase (APX), two central enzymes of reactive oxygen species detoxification, across the highly diverse clade Eugenozoa. This clade encompasses free-living phototrophic and heterotrophic flagellates, as well as obligate parasites of insects, vertebrates, and plants. We present evidence of several independent acquisitions of CAT by horizontal gene transfers and evolutionary novelties associated with the APX presence. We posit that Euglenozoa recruit these detoxifying enzymes for specific molecular tasks, such as photosynthesis in euglenids and membrane-bound peroxidase activity in kinetoplastids and some diplonemids.

scholarly journals Armillifer Infections in Humans: A Systematic Review

2019 ◽  
Vol 4 (2) ◽  
pp. 80 ◽  
Author(s):  
Petros Ioannou ◽  
Rodanthi Vamvoukaki
Keyword(s):  
Systematic Review ◽  
Abdominal Pain ◽  
Hepatic Encephalopathy ◽  
Human Disease ◽  
Human Infection ◽  
Ocular Infection ◽  
Obligate Parasites ◽  
Permanent Loss ◽  
Treatment Data ◽  
Undercooked Meat

Armillifer is a genus of obligate parasites belonging to the Pentastomida subclass that was first described as a cause of human disease in 1847. Human infection by Armillifer is rare and not widely known. These parasites are transmitted to humans by handling or eating undercooked meat from infected snakes, which are the definitive hosts, or oral uptake of environmental ova. The aim of this systematic review was to record all available evidence regarding infections by Armillifer in humans. A systematic review of PubMed (through 21 December 2018) for studies providing epidemiological, clinical, microbiological, as well as treatment data and outcomes of Armillifer infections was conducted. A total of 26 studies, containing data of 40 patients, were eventually included in the analysis. The most common sites of infection were the peritoneal cavity, the liver, the lower respiratory and the abdominal tract. The commonest infecting species was A. armillatus and most patients were asymptomatic; however, when symptoms occurred, the commonest was abdominal pain, even though unusual presentations occurred, such as hepatic encephalopathy or neurologic symptoms. Most cases were diagnosed at surgery or by imaging, and most patients were not treated. Mortality was low, but the majority of the cases with ocular infection lead to permanent loss of vision.

ULTRASTRUCTURE OF THE HYPHAE AND HAUSTORIA OF PHYTOPHTHORA INFESTANS AND HYPHAE OF P. PARASITICA

1966 ◽  
Vol 44 (11) ◽  
pp. 1495-1503 ◽  
Author(s):  
Mary A. Ehrlich ◽  
Howard G. Ehrlich
Keyword(s):  
Endoplasmic Reticulum ◽  
Cell Wall ◽  
Phytophthora Infestans ◽  
Current Literature ◽  
Lipid Bodies ◽  
Potato Varieties ◽  
Parasitic Fungi ◽  
Obligate Parasites ◽  
Tubular Endoplasmic Reticulum ◽  
Cytoplasmic Continuity

The ultrastructure of the mycelium of both Phytophthora infestans and P. parasitica is consistent with that reported for other Oomycetes. A distinct plasmalemma, porate nuclei, tubular endoplasmic reticulum, mitochondria with tubular cristae, Golgi dictyosomes, and lipid bodies are present within the protoplast. The haustoria produced by P. infestans in the leaves of susceptible potato varieties consist of an expanded haustorial head surrounded by a fungus wall which is continuous with the wall of the intercellular mycelium. The haustorium lacks the long narrow stalk or neck often associated with this organ, and there is considerable cytoplasmic continuity between the haustorium and the intercellular mycelium. All P. infestans haustoria observed were anucleate and generally contained only a few mitochondria and sparse endoplasmic reticulum. The haustorium is enclosed in an encapsulation surrounded by a membrane which is continuous with the host plasmalemma. There is no evidence, around any portion of the haustorium, of a sheath originating from the cell wall of the host. A survey of the current literature on the ultrastructure of the Eumycotinia shows that the parasitic fungi exhibit no unique cytoplasmic features when compared with non-parasitic fungi, and the ultrastructure of the haustoria-producing facultative saprophyte is similar to that of the obligate parasites.

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