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Topic review
Updated time: 14 Apr 2021
Submitted by: Antimo Di Maro
Definition: Ageritin is a specific ribonuclease, extracted from the edible mushroomCyclocybe aegerita(synonymAgrocybe aegerita), which cleaves a single phosphodiester bond located within the universally conserved alpha-sarcin loop (SRL) of 23–28S rRNAs.This toxin is the prototype of ribotoxin-like protein family present in edible mushroom and possesses antifungal/antiviral activities and selective cytotoxicity against tumor cells with potential use in biotechnological applications (as bio-insecticides or antitumor agents).
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Topic review
Updated time: 22 Jun 2021
Submitted by: Joselito Quirino
Definition: Alkenylbenzenes are potentially toxic (genotoxic and carcinogenic) compounds present in plants such as basil, tarragon, anise star and lemongrass. These plants are found in various edible consumer products, e.g., popularly used to flavour food. Thus, there are concerns about the possible health consequences upon increased exposure to alkenylbenzenes especially due to food intake. It is therefore important to constantly monitor the amounts of alkenylbenzenes in our food chain.
Topic review
Updated time: 16 Aug 2021
Submitted by: Patrick Monteiro
Definition: Anabaenopeptins (APs) are structurally diverse peptides widely distributed in distinct ecosystems among cyanobacteria. Some structural features of these molecules are shared with other cyanotoxins, such as the presence of modified residues, exocyclic amino acids, circular structure, and amino acids in D-configuration. However, among the cyanopeptides, the ureido linkage is exclusively found in APs. Thus, these cyclic peptides demonstrate toxicity and structural diversity which will be explored in this topic, including biotechnological and ecological relevance, and their distribution.
Entry Collection : Environmental Sciences
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Topic review
Updated time: 23 Aug 2021
Submitted by: Victoria Shubina
Definition: Polyphenols are the most numerous and widely distributed compounds of plant origin. They are involved in various processes of the growth and development of plants, and their protection against unfavorable environmental factors. They enter the body of humans and animals with plant food. The intake of polyphenols or polyphenol-rich food products might be associated with a lower risk of cardiovascular, neurodegenerative, and other diseases. More than 8000 polyphenols have been identified; of these, more than 4000 compounds belong to the group of flavonoids. In nature, polyphenols occur as monomers, oligomers, and polymers (proanthocyanidins, condensed tannins). There is also evidence indicating that, during the storage and aging of food products and beverages with a high content of flavonoids, the latter react with carbonyl compounds such as acetaldehyde, methylglyoxal, glyoxylic acid, and furfurol, which results in the formation of monomeric, oligomeric, and polymeric adducts.
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Topic review
Updated time: 10 Sep 2021
Submitted by: Hesham M. Korashy
Definition: AhR is a ligand-activated transcription factor that belongs to basic-helix-loop-helix (bHLH)/Per-ARNT-Sim (PAS) family, which is involved in the regulation of cell differentiation, proliferation, and cancer imitation. AhR plays an important role in various physiological pathways, including host defense, immunity, stem cell maintenance, cell differentiation, and xenobiotic metabolism. It was initially believed that AhR is activated only by a group of environmental pollutants, such as polycyclic aromatic hydrocarbons (PAHs).
Entry Collection : Environmental Sciences
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Topic review
Updated time: 16 Aug 2021
Submitted by: Marieke Hoonakker
Definition: One of the main virulence factors produced by Bordetella pertussis is pertussis toxin (PTx) which, in its inactivated form, is the major component of all marketed acellular pertussis vaccines. PTx ADP ribosylates Gαi proteins, thereby affecting the inhibition of adenylate cyclases and resulting in the accumulation of cAMP. Apart from this classical model, PTx also activates some receptors and can affect various ADP ribosylation- and adenylate cyclase-independent signalling pathways. Due to its potent ADP-ribosylation properties, PTx has been used in many research areas. Initially the research primarily focussed on the in vivo effects of the toxin, including histamine sensitization, insulin secretion and leukocytosis. Nowadays, PTx is also used in toxicology research, cell signalling, research involving the blood–brain barrier, and testing of neutralizing antibodies. However, the most important area of use is testing of acellular pertussis vaccines for the presence of residual PTx. In vivo models and in vitro assays for PTx often reflect one of the toxin’s properties or details of its mechanism.
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Topic review
Updated time: 02 Jul 2021
Submitted by: Marco Diociaiuti
Definition: It has been proposed that a “common core” of pathologic pathways exists for the large family of amyloid-associated neurodegenerations, including Alzheimer’s, Parkinson’s, type II diabetes and Creutzfeldt–Jacob’s Disease. Aggregates of the involved proteins, independently from their primary sequence, induced neuron membrane permeabilization able to trigger an abnormal Ca2+ influx leading to synaptotoxicity, resulting in reduced expression of synaptic proteins and impaired synaptic transmission. Emerging evidence is now focusing on low-molecular-weight prefibrillar oligomers (PFOs), which mimic bacterial pore-forming toxins that form well-ordered oligomeric membrane-spanning pores. At the same time, the neuron membrane composition and its chemical microenvironment seem to play a pivotal role. However, up to now the existence of a specific “common structure” of the toxic aggregate, and a “common mechanism” by which it induces neuronal damage, synaptotoxicity and impaired synaptic transmission, is still an open hypothesis. In this review, we gathered information concerning this hypothesis, focusing on the proteins linked to several amyloid diseases. We noted commonalities in their structure and membrane activity, and their ability to induce Ca2+ influx, neurotoxicity, synaptotoxicity and impaired synaptic transmission.
Entry Collection : Neurodegeneration
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Topic review
Updated time: 18 Jun 2021
Submitted by: Rahim Khan
Definition: The pre-harvest biocontrol approach currently used includes laboratory inoculations using non-aflatoxigenic strains of Aspergillus flavus. This strategy effectively suppresses the indigenous aflatoxigenic strains and reduces aflatoxin accumulation in sweetcorn. The reduction in AFB1 with population expressions of AF+ strains by the AF− strains and supports the notion of competitive exclusion through vigorous development and propagation of the non-aflatoxigenic fungi.
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Topic review
Updated time: 16 Sep 2021
Submitted by: Agnieszka Niemiec
Definition: Dried Blood Spot (DBS) is becoming very popular in various medical fields, especially in toxicology. Nowadays, it is commonly used in newborn screening for inherited or congenital diseases. DBS does not require trained medical staff to collect the samples and can be effortlessly transported to the laboratory, which makes it an easy and quick procedure. A venous blood spot, collected from a finger or a heel, is put on the special paper card, which can result in a different distribution of blood and concentration of detecting substances. DBS enables drugs analysis, detecting substances of abuse as well as trace elements. It also serves its purpose in newborn screening and testing in SARS-CoV-2 serology. DBS is certain to develop rapidly and become even more worldwide used.
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Topic review
Updated time: 14 Jul 2021
Submitted by: Paul Hyman
Definition: Engineered bacteriophages (phages) are bacteriophages that have been genetically or chemically altered in some way to create or improve a property for an application, although it would be equally valid to use this term for phages altered for research. Application-directed properties can include: enhanced bacterial killing to improve phage therapy; insertion of reporter genes to facilitate biosensor-mediated detection; insertion of targeting peptides to a virion surface protein to enhance binding properties to bacteria or other types of cells; attachment of non-protein molecules (e.g. antibiotics or nanoparticles) to phage capsid surface proteins to facilitate phage-mediated delivery; anchoring of phages to a surface to improve target capture. It is also possible to combine modifications to develop, for example, a phage-based cancer treatment that has binding peptides for cancer cell targeting and is conjugated to either a radioisotope nanoparticle or chemotherapy drug to improve delivery.
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