scholarly journals Does the chemistry of fungal pigments demand the existence of photoactivated defense strategies in basidiomycetes?

2021 ◽  
Author(s):  
Bianka Siewert
Keyword(s):  
Defense Mechanism ◽  
Cross Linking ◽  
Mushroom Species ◽  
Structural Requirements ◽  
Defense Strategies ◽  
Fungal Pigments

AbstractThe well-known photosensitizers hypericin, harmane, and emodin are typical pigments of certain mushroom species—is this a coincidence or an indication towards a photoactivated defense mechanism in the phylum Basidiomycota? This perspective article explores this hypothesis by cross-linking the chemistry of fungal pigments with structural requirements from known photosensitizers and insights from photoactivated strategies in the kingdom Plantae. Thereby, light is shed on a yet unexplored playground dealing with ecological questions, photopharmaceutical opportunities, and biotechnological potentials.

scholarly journals Are terrestrial isopods able to use stridulation and vibrational communication as forms of intra and interspecific signaling and defense strategies as insects do? A preliminary study in Armadillo officinalis

2019 ◽  
Vol 107 (1) ◽  
Author(s):  
Sofia Cividini ◽  
Spyros Sfenthourakis ◽  
Giuseppe Montesanto
Keyword(s):  
Defense Mechanism ◽  
High Sensitivity ◽  
Specific Substrate ◽  
Test Apparatus ◽  
Defense Strategies ◽  
Terrestrial Isopods ◽  
Adverse Conditions ◽  
Secondary Form ◽  
Preliminary Study ◽  
Species Specific

AbstractThe capability of producing sounds and vibrations is well known in insects and is thought to be a form of intra- and interspecific communication. Sounds and vibrations are used and modulated for several aims such as interacting with conspecifics, getting information from the environment, and defending against predators. This phenomenon is less known but also present in other arthropods, including a few roller-type terrestrial isopods. In this study, we used a Y-shape test apparatus to investigate the behavior of adult individuals of Armadillo officinalis Duméril, 1816 (Crustacea: Isopoda: Oniscidea) when exposed to two particular vibrational stimuli, namely species-specific stridulations and non-specific substrate-borne vibrations. Our results showed that adults of A. officinalis significantly react to the presence of both types of vibrational stimuli, by moving away from the vibrational source as if they experienced these vibrations as a sign of danger or disturbance. A. officinalis can produce stridulations only when it rolls into a ball during the so-called conglobation, a possible defense mechanism against predators. Stridulation might thus be a secondary form of defense used during conglobation to deter a predator following contact with it and might be experienced as an alert by conspecifics nearby. The high sensitivity to non-specific substrate-borne vibrations might provide A. officinalis with the possibility to anticipate dangers and adverse conditions, giving it a better chance of survival.

scholarly journals The Use of Winter Water Temperature and Food Composition by the Copepod Cyclops vicinus (Uljanin, 1875) to Provide a Temporal Refuge from Fish Predation

Biology ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 393
Author(s):  
Jong-Yun Choi ◽  
Seong-Ki Kim
Keyword(s):  
Population Growth ◽  
Defense Mechanism ◽  
Morphological Changes ◽  
Lepomis Macrochirus ◽  
Fish Predation ◽  
Food Composition ◽  
Food Sources ◽  
Defense Strategies ◽  
Cyclops Vicinus ◽  
The Stability

Frequent predation induces various defense strategies in prey, including morphological changes or migration patterns in zooplankton. We hypothesized that the winter dominance of Cyclops vicinus in the Upo Wetlands, South Korea, is an evolved temporal defense mechanism to avoid fish predation. Long-term data (2014–2019) showed that fish consumed the most cyclopoid copepods from spring to autumn. Lepomis macrochirus preferentially consumed C. vicinus; thus, C. vicinus density was lower from spring to autumn. However, C. vicinus was abundant in winter when fish consumed fewer copepods. Nauplii density began to increase in late autumn (October–November), and their population growth was fueled through consumption of Cyclotella sp. and Rhodomonas sp. Culture experiments showed that Cyclotella sp. contributed more to the growth stage (copepodite or subadult) after nauplii than Rhodomonas sp. C. vicinus density was lower in the winters of 2013 and 2016 when the densities of these phytoplankton prey species were lower. In summary, although winter conditions were suitable for copepod survival and population growth, C. vicinus relied heavily on the diversity and species composition of its food sources. The winter dominance of C. vicinus could increase regional biodiversity and contribute significantly to the stability of the freshwater food web.

scholarly journals TGFβ Suppresses Type 2 Immunity to Cancer

2020 ◽  
Author(s):  
Ming Liu ◽  
Fengshen Kuo ◽  
Kristelle J. Capistrano ◽  
Davina Kang ◽  
Briana G. Nixon ◽  
...  
Keyword(s):  
T Cells ◽  
Cancer Cell ◽  
Cancer Progression ◽  
Transforming Growth Factor ◽  
Defense Mechanism ◽  
Transforming Growth Factor Β ◽  
Defense Strategies ◽  
Type 2 Immunity ◽  
Immunological Mechanisms

SummaryThe immune system employs two distinct defense strategies against infections: pathogen elimination typified by type 1 immunity, and pathogen containment exemplified by type 2 immunity in association with tissue repair. Akin to infectious diseases, cancer progresses with cancer cell acquisition of microorganism-like behavior propagating at the expense of the host. While immunological mechanisms of cancer cell elimination are well defined, whether immune-mediated cancer cell containment can be induced is poorly understood. Here we show that ablation of transforming growth factor-β receptor II (TGFβRII) in CD4+ T cells promotes tumor tissue healing and halts cancer progression. Notably, the restorative response is dependent on the T helper 2 cytokine IL-4 fortifying vasculature organization that spares only proximal layers of cancer cells from hypoxia, nutrient starvation and death. Thus, type 2 immunity represents an effective cancer defense mechanism, and TGFβ signaling in helper T cells may be targeted for novel cancer immunotherapy.

scholarly journals Structural requirements for photo-induced RNA-protein cross-linking

2021 ◽  
Author(s):  
Anna Knörlein ◽  
Chris Sarnowski ◽  
Tebbe de Vries ◽  
Moritz Stoltz ◽  
Michael Götze ◽  
...  
Keyword(s):  
Cross Linking ◽  
Structural Requirements ◽  
Protein Cross Linking

Influence of Calcium Ions on the Plant Cell Surface: Membrane Fusions and Conformational Changes

1974 ◽  
Vol 32 ◽  
pp. 154-155
Author(s):  
D. James Morré ◽  
Charles E. Bracker ◽  
William J. VanDerWoude
Keyword(s):  
Cell Wall ◽  
Cell Surface ◽  
Conformational Changes ◽  
Calcium Ions ◽  
Surface Membrane ◽  
Carboxyl Groups ◽  
Cross Linking ◽  
Ultrastructural Evidence ◽  
Glycine Max L ◽  
Wall Extensibility

Calcium ions in the concentration range 5-100 mM inhibit auxin-induced cell elongation and wall extensibility of plant stems. Inhibition of wall extensibility requires that the tissue be living; growth inhibition cannot be explained on the basis of cross-linking of carboxyl groups of cell wall uronides by calcium ions. In this study, ultrastructural evidence was sought for an interaction of calcium ions with some component other than the wall at the cell surface of soybean (Glycine max (L.) Merr.) hypocotyls.

Embedding Procedure for Water Swollen Samples

1970 ◽  
Vol 28 ◽  
pp. 504-505
Author(s):  
Ann M. Thomas ◽  
Virginia Shemeley
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Ion Exchange ◽  
Structural Changes ◽  
Cross Linking ◽  
Ion Exchange Resins ◽  
Transmission Electron ◽  
First Pass ◽  
Exchange Resins

Those samples which swell rapidly when exposed to water are, at best, difficult to section for transmission electron microscopy. Some materials literally burst out of the embedding block with the first pass by the knife, and even the most rapid cutting cycle produces sections of limited value. Many ion exchange resins swell in water; some undergo irreversible structural changes when dried. We developed our embedding procedure to handle this type of sample, but it should be applicable to many materials that present similar sectioning difficulties.The purpose of our embedding procedure is to build up a cross-linking network throughout the sample, while it is in a water swollen state. Our procedure was suggested to us by the work of Rosenberg, where he mentioned the formation of a tridimensional structure by the polymerization of the GMA biproduct, triglycol dimethacrylate.

The Current Situation in Chemical Stabilization of Biological Materials

1972 ◽  
Vol 30 ◽  
pp. 132-133
Author(s):  
John H. Luft
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Osmium Tetroxide ◽  
Molecular Level ◽  
Cross Linking ◽  
Chemical Stabilization ◽  
Specimen Preparation ◽  
Sufficient Condition ◽  
Radio Telescopes

With information processing devices such as radio telescopes, microscopes or hi-fi systems, the quality of the output often is limited by distortion or noise introduced at the input stage of the device. This analogy can be extended usefully to specimen preparation for the electron microscope; fixation, which initiates the processing sequence, is the single most important step and, unfortunately, is the least well understood. Although there is an abundance of fixation mixtures recommended in the light microscopy literature, osmium tetroxide and glutaraldehyde are favored for electron microscopy. These fixatives react vigorously with proteins at the molecular level. There is clear evidence for the cross-linking of proteins both by osmium tetroxide and glutaraldehyde and cross-linking may be a necessary if not sufficient condition to define fixatives as a class.

Parathyroid gland before and after cisplatin treatment

1987 ◽  
Vol 45 ◽  
pp. 860-861
Author(s):  
S.K. Aggarwal ◽  
J.M. Fadool
Keyword(s):  
Parathyroid Gland ◽  
Wistar Rats ◽  
Antitumor Agent ◽  
The Body ◽  
Cross Linking ◽  
Limiting Factor ◽  
Hormonal Changes ◽  
Primary Mechanism ◽  
Before And After ◽  
Dna Strands

Cisplatin (CDDP) a potent antitumor agent suffers from severe toxic side effects with nephrotoxicity being the major dose-limiting factor, The primary mechanism of its action has been proposed to be through its cross-linking DNA strands. It has also been shown to inactivate various transport enzymes and induce hypocalcemia and hypomagnesemia that may be the underlying cause for some of its toxicities. The present is an effort to study its influence on the parathyroid gland for any hormonal changes that control calcium levels in the body.Male Swiss Wistar rats (Crl: (WI) BR) weighing 200-300 g and of 60 days in age were injected (ip) with cisplatin (7mg/kg in normal saline). The controls received saline injections only. The animals were injected (iv) with calcium (0.5 ml of 10% calcium gluconate/day) and were killed by decapitation on day 1 through 5. Trunk blood was collected in heparinized tubes.

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