scholarly journals Advances on the Visualization of the Internal Structures of the European Mistletoe: 3D Reconstruction Using Microtomography

2021 ◽  
Vol 12 ◽  
Author(s):  
Max D. Mylo ◽  
Mara Hofmann ◽  
Alexander Delp ◽  
Ronja Scholz ◽  
Frank Walther ◽  
...  

The European mistletoe (Viscum album) is a dioecious epiphytic evergreen hemiparasite that develops an extensive endophyte enabling the absorption of water and mineral salts from the host tree, whereas the exophytic leaves are photosynthetically active. The attachment mode and host penetration are well studied, but little information is available about the effects of mistletoe age and sex on haustorium-host interactions. We harvested 130 plants of Viscum album ssp. album growing on host branches of Aesculus flava for morphological and anatomical investigations. Morphometric analyses of the mistletoe and the (hypertrophied) host interaction site were correlated with mistletoe age and sex. We recorded the morphology of the endophytic systems of various ages by using X-ray microtomography scans and corresponding stereomicroscopic images. For detailed anatomical studies, we examined thin stained sections of the mistletoe-host interface by light microscopy. The diameter and length of the branch hypertrophy showed a positive linear correlation with the age of the mistletoe. Correlations with their sex were only found for ratios between host branch and hypertrophy size. A female bias of about 76% was found. In a 4-year-old mistletoe, several small, almost equally sized sinkers and the connected cortical strands extend over more than 5 cm within the host branch. In older mistletoes, one main sinker was predominant and occupied an increasingly large proportion of the stem cross-section. Bands of vessels ran along the axis of the wedge-shaped haustoria and sinkers and bent sideways toward the mistletoe-host interface. At the interface, the vascular elements of the host wood changed their direction and formed vortices near the haustorium.

2021 ◽  
Vol 6 (3) ◽  
pp. 118
Author(s):  
Ferenc Orosz

In 2009, apicortin was identified in silico as a characteristic protein of apicomplexans that also occurs in the placozoa, Trichoplax adhaerens. Since then, it has been found that apicortin also occurs in free-living cousins of apicomplexans (chromerids) and in flagellated fungi. It contains a partial p25-α domain and a doublecortin (DCX) domain, both of which have tubulin/microtubule binding properties. Apicortin has been studied experimentally in two very important apicomplexan pathogens, Toxoplasma gondii and Plasmodium falciparum. It is localized in the apical complex in both parasites. In T. gondii, apicortin plays a key role in shaping the structure of a special tubulin polymer, conoid. In both parasites, its absence or downregulation has been shown to impair pathogen–host interactions. Based on these facts, it has been suggested as a therapeutic target for treatment of malaria and toxoplasmosis.


Author(s):  
Liang Ren ◽  
Daonan Shen ◽  
Chengcheng Liu ◽  
Yi Ding

The human oral cavity harbors approximately 1,000 microbial species, and dysbiosis of the microflora and imbalanced microbiota-host interactions drive many oral diseases, such as dental caries and periodontal disease. Oral microbiota homeostasis is critical for systemic health. Over the last two decades, bacterial protein phosphorylation systems have been extensively studied, providing mounting evidence of the pivotal role of tyrosine and serine/threonine phosphorylation in oral bacterial dysbiosis and bacteria-host interactions. Ongoing investigations aim to discover novel kinases and phosphatases and to understand the mechanism by which these phosphorylation events regulate the pathogenicity of oral bacteria. Here, we summarize the structures of bacterial tyrosine and serine/threonine kinases and phosphatases and discuss the roles of tyrosine and serine/threonine phosphorylation systems in Porphyromonas gingivalis and Streptococcus mutans, emphasizing their involvement in bacterial metabolism and virulence, community development, and bacteria-host interactions.


Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 400
Author(s):  
Elisa Saccon ◽  
Adriana Vitiello ◽  
Marta Trevisan ◽  
Cristiano Salata ◽  
Giorgio Palù

The 6th European Seminar in Virology (EuSeV) was held in Bertinoro, Italy, 22–24 June 2018, and brought together international scientists and young researchers working in the field of Virology. Sessions of the meeting included: virus–host-interactions at organism and cell level; virus evolution and dynamics; regulation; immunity/immune response; and disease and therapy. This report summarizes lectures by the invited speakers and highlights advances in the field.


2014 ◽  
Vol 11 (1) ◽  
pp. 185-194 ◽  
Author(s):  
D. S. Maat ◽  
N. J. Bale ◽  
E. C. Hopmans ◽  
A.-C. Baudoux ◽  
J. S. Sinninghe Damsté ◽  
...  

Abstract. Recent studies showed changes in phytoplankton lipid composition during viral infection and have indicated roles for specific lipids in the mechanisms of algal virus-host interaction. To investigate the generality of these findings and obtain a better understanding of the allocation of specific lipids to viruses, we studied the intact polar lipid (IPL) composition of virally infected and non-infected cultures of the prymnesiophyte Phaeocystis globosa G(A) and its lytic virus PgV-07T. The P. globosa IPL composition was relatively stable over a diel cycle and not strongly affected by viral infection. Glycolipids, phospholipids and betaine lipids were present in both the host and virus, although specific groups such as the diacylglyceryl-hydroxymethyltrimethyl-β-alanines and the sulfoquinovosyldiacylglycerols, were present in a lower proportion or were not detected in the virus. Viral glycosphingolipids (vGSLs), which have been shown to play a role in the infection strategy of the virus EhV-86, infecting the prymnesiophyte Emiliania huxleyi CCMP374, were not encountered. Our results show that the involvement of lipids in virus–algal host interactions can be very different amongst virus–algal host systems.


2020 ◽  
Author(s):  
Sean Kennedy ◽  
Mélanie M Leroux ◽  
Alexis Simons ◽  
Brice Malve ◽  
Marc Devocelle ◽  
...  

Human gastroenteritis viruses are amid the major causes of disease worldwide, responsible for more than 2 million deaths per year. Human noroviruses play a leading role in the gastroenteritis outbreaks and the continuous emergence of new strains contributes to the significant morbidity and mortality. Many aspects of the viral entry and infection process remain unclear, including the major response of the host cell to the virus, which is the trigger of several programmed cell death related mechanisms. In this review, we assessed apoptosis and autophagy at various stages in the infection process to provide better understanding of the viral–host interaction. This brings us closer to fully understanding how noroviruses work, thus allowing the development of specific antiviral therapies.


2018 ◽  
Vol 32 (05) ◽  
pp. 1850054 ◽  
Author(s):  
Zhen Yao ◽  
Chun-Jian Liu ◽  
Hang Lv

The high-pressure deformation and polymerization of peapod structure (C[Formula: see text]H[Formula: see text] filled into (13, 0) single-walled carbon nanotube) is studied by using density function theory. The guest–host interaction mechanism under pressure is analyzed by combining the van der Waals (vdW) potential with the electron localization function (ELF). Our studies show that the cross-section of the filled single-walled carbon nanotube changes from a circle into an ellipse shape, and then into a walnut shape with the transition pressures of 3 GPa and 10 GPa, respectively. The intertubular bonding of adjacent tubes occurs at 17 GPa, 30 GPa, 32 GPa, 82 GPa and 152 GPa. The attractive and repulsive guest–host interactions are exhibited for the pressures lower and higher than 10 GPa, respectively. Except for the ambient pressure structure, six stable high pressure structures, which can hold their structures when the pressure is released, are identified by combining the systematic binding energy with geometry optimization.


Open Biology ◽  
2021 ◽  
Vol 11 (3) ◽  
Author(s):  
Monikaben Padariya ◽  
Umesh Kalathiya ◽  
Sara Mikac ◽  
Katarzyna Dziubek ◽  
Maria C. Tovar Fernandez ◽  
...  

Virus–host interactions form an essential part of every aspect of life, and this review is aimed at looking at the balance between the host and persistent viruses with a focus on the immune system. The virus–host interaction is like a cat-and-mouse game and viruses have developed ingenious mechanisms to manipulate cellular pathways, most notably the major histocompatibility (MHC) class I pathway, to reside within infected cell while evading detection and destruction by the immune system. However, some of the signals sensing and responding to viral infection are derived from viruses and the fact that certain viruses can prevent the infection of others, highlights a more complex coexistence between the host and the viral microbiota. Viral immune evasion strategies also illustrate that processes whereby cells detect and present non-self genetic material to the immune system are interlinked with other cellular pathways. Immune evasion is a target also for cancer cells and a more detailed look at the interfaces between viral factors and components of the MHC class I peptide-loading complex indicates that these interfaces are also targets for cancer mutations. In terms of the immune checkpoint, however, viral and cancer strategies appear different.


2018 ◽  
Author(s):  
Carmen Escudero-Martinez ◽  
Daniel J. Leybourne ◽  
Jorunn I.B. Bos

AbstractAphids are phloem-feeding insects that cause economic losses to crops globally. Whilst aphid interactions with susceptible plants and partially resistant genotypes have been well characterised with regards to aphid probing and feeding behaviour, the interactions with non-natural host species are not well understood. Using aphid choice assays with the broad host range pest Myzus persicae and the cereal pest Rhopalosiphum padi we show that about 10% of aphids settle on non-/poor-host species over a 24h time period. We used the Electrical Penetration Graph technique to assess aphid probing and feeding behaviour during the non-/poor-host interactions. In the Arabidopsis non-host interaction with the cereal pest R. padi aphids were unable to reach and feed from the phloem, with resistance likely residing in the mesophyll cell layer. In the barley poor-host interaction with M. persicae, resistance is likely phloem-based as aphids were able to reach the phloem but ingestion was reduced compared with the host interaction. Overall our data suggests that plant resistance to aphids in non-host and poor-host interactions with these aphid species likely resides in different plant cell layers. Future work will take into account specific cell layers where resistances are based to dissect the underlying mechanisms and gain a better understanding of how we may improve crop resistance to aphids.


2013 ◽  
Vol 10 (7) ◽  
pp. 11705-11727 ◽  
Author(s):  
D. S. Maat ◽  
N. J. Bale ◽  
E. C. Hopmans ◽  
A.-C. Baudoux ◽  
J. S. Sinninghe Damsté ◽  
...  

Abstract. Recent studies showed changes in phytoplankton lipid composition during viral infection and have indicated roles for specific lipids in the mechanisms of algal virus-host interaction. To investigate the generality of these findings and obtain a better understanding of the allocation of specific lipids to viruses, we studied the intact polar lipid (IPL) composition of virally infected and non-infected cultures of the Prymnesiophyte Phaeocystis globosa G(A) and its lytic virus PgV-07T. The P. globosa IPL composition was relatively stable over a diel cycle and not strongly affected by viral infection. Glycolipids, phospholipids and betaine lipids were present in both the host and virus, although specific groups such as the diacylglyceryl-hydroxymethyltrimethyl-β-alanines and the sulfoquinovosyldiacylglycerols, were present in a lower proportion or were not detected in the virus. Viral glycosphingolipids (vGSLs), which have been shown to play a role in the infection strategy of the virus EhV-86, infecting the Prymnesiophyte Emiliania huxleyi CCMP374, were not encountered. Our results show that the involvement of lipids in virus-algal host interactions can be very different amongst virus-algal host systems.


2021 ◽  
Author(s):  
Julieth Irene Murillo Silva ◽  
Bijay Jassal ◽  
Maria Adelaida Gomez ◽  
Henning Hermjakob

Leishmaniasis is a parasitic disease with a wide range of clinical manifestations. Multiple aspects of the Leishmania-host interaction, such as genetic factors and modulation of microbicidal functions in host cells, influence pathogenesis, disease severity and treatment outcome. How do scientists contend with this complexity? Here, we work towards representing detailed, contextual knowledge on Leishmania-host interactions in the Reactome pathway database to facilitate the extraction of novel mechanistic insights from existing datasets. The Reactome database uses a hierarchy of abstractions that allows for the incorporation of detailed contextual knowledge on biological processes matched to differentially expressed genes. It also includes tools for enhanced over-representation analysis that exploits this extra information. We conducted a systematic curation of published studies documenting different aspects of the Leishmania-host interaction. The 'Leishmania infection pathway' included four sub-pathways: phagocytosis, killing mechanisms, cell recruitment, and Leishmania parasite growth and survival. As proof-of-principle of the usefulness of the released pathway, we used it to analyze two previously released transcriptomic datasets of human and murine macrophages infected with Leishmania. Our results provide insights on the participation of ADORA2B signaling pathway in the modulation of IL10 and IL6 in infected macrophages. This work opens the way for other researchers to contribute to, and make use of, the Reactome database.


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