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Cupiennins
Cupiennins are a group of small cytolytic peptides from the venom of the wandering spider '' Cupiennius salei''. They are known to have high bactericidal, insecticidal and haemolytic activities. They are chemically cationic α-helical peptides. They were isolated and identified in 2002 as a family of peptides called cupiennin 1. The sequence was determined by a process called Edman degradation, and the family consists of cupiennin 1a, cupiennin 1b, cupiennin 1c, and cupiennin 1d. The amino acid sequences of cupiennin 1b, c, and d were obtained by a combination of sequence analysis and mass spectrometric measurements of comparative tryptic peptide mapping. Even though they are not strong toxins, they do enhance the effect of the spider venom by synergistically enhancing other components of the venom, such CSTX. Chemical property All cupiennins are composed of 35 amino acid residues and are characterised by a more hydrophobic N-terminal chain region and a C-terminus composed p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cupiennius Salei
''Cupiennius salei'', commonly called the tiger bromeliad spider, are large bodied, actively-hunting spiders that are part of the family Trechaleidae. They are found in Central America and Mexico, while other species in the genus are also found in various parts of South America. They are visually similar to another group called wandering spiders (but also see that diverse kinds often get mistakenly called banana spiders). More precisely, this species naturally occurs in Eastern Mexico, Guatemala, Belize, Honduras, Nicaragua and possibly into northwestern Costa Rica. Yet, it has also been introduced to various parts of the world either by accidental imports (such as in the early 20th century from banana plantations), or deliberately introduced elsewhere as either a laboratory model organism or an exotic pet. However, it has not yet been recorded as established in the wild outside of its native Mexico and Central America. In the mid-1950s it was realised that the spider is an ideal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CSTX
CSTX (for "'' Cupiennius salei'' toxins") is a name given to a group of closely related neurotoxic peptides present in the venom of the wandering spider ''Cupiennius salei''. There are twenty types so far described for this protein group. However, some are reclassified into cupiennins group of toxin, including CSTX-3, -4, -5, and -6, because of their chemical affinity. The first thirteen were isolated and identified in 1994 by Lucia Kuhn-Nentwig, Johann Schaller, and Wolfgang Nentwig of the Zoological Institute at the University of Bern, Switzerland. The different types are most likely the products of splicing variant of the same gene. They are all L-type calcium channel blockers, and also exhibit cytolytic activity by forming an alpha-helix across the cell membrane in mammalian neurons. They also inhibit voltage-gated calcium channels in insect neurons. Types The best understood members of the neurotoxin group of CSTX are: CSTX-1 CSTX-1 is the most abundant peptide of the ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cytolytic
Cytolysis, or osmotic lysis, occurs when a cell bursts due to an osmotic imbalance that has caused excess water to diffuse into the cell. Water can enter the cell by diffusion through the cell membrane or through selective membrane channels called aquaporins, which greatly facilitate the flow of water. It occurs in a hypotonic environment, where water moves into the cell by osmosis and causes its volume to increase to the point where the volume exceeds the membrane's capacity and the cell bursts. The presence of a cell wall prevents the membrane from bursting, so cytolysis only occurs in animal and protozoa cells which do not have cell walls. The reverse process is plasmolysis. In bacteria Osmotic lysis would be expected to occur when bacterial cells are treated with a hypotonic solution with added lysozyme, which destroys the bacteria's cell walls. Prevention Different cells and organisms have adapted different ways of preventing cytolysis from occurring. For example, the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alanine
Alanine (symbol Ala or A), or α-alanine, is an α-amino acid that is used in the biosynthesis of proteins. It contains an amine group and a carboxylic acid group, both attached to the central carbon atom which also carries a methyl group side chain. Consequently, its IUPAC systematic name is 2-aminopropanoic acid, and it is classified as a nonpolar, aliphatic α-amino acid. Under biological conditions, it exists in its zwitterionic form with its amine group protonated (as −NH3+) and its carboxyl group deprotonated (as −CO2−). It is non-essential to humans as it can be synthesised metabolically and does not need to be present in the diet. It is encoded by all codons starting with GC (GCU, GCC, GCA, and GCG). The L-isomer of alanine (left-handed) is the one that is incorporated into proteins. L-alanine is second only to leucine in rate of occurrence, accounting for 7.8% of the primary structure in a sample of 1,150 proteins. The right-handed form, D-alanine, occurs in p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spider Toxins
Spiders (order Araneae) are air-breathing arthropods that have eight legs, chelicerae with fangs generally able to inject venom, and spinnerets that extrude silk. They are the largest order of arachnids and rank seventh in total species diversity among all orders of organisms. Spiders are found worldwide on every continent except for Antarctica, and have become established in nearly every land habitat. , 50,356 spider species in 132 families have been recorded by taxonomists. However, there has been debate among scientists about how families should be classified, with over 20 different classifications proposed since 1900. Anatomically, spiders (as with all arachnids) differ from other arthropods in that the usual body segments are fused into two tagmata, the cephalothorax or prosoma, and the opisthosoma, or abdomen, and joined by a small, cylindrical pedicel, however, as there is currently neither paleontological nor embryological evidence that spiders ever had a separate th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
N-terminus
The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amine group is bonded to the carboxylic group of another amino acid, making it a chain. That leaves a free carboxylic group at one end of the peptide, called the C-terminus, and a free amine group on the other end called the N-terminus. By convention, peptide sequences are written N-terminus to C-terminus, left to right (in LTR writing systems). This correlates the translation direction to the text direction, because when a protein is translated from messenger RNA, it is created from the N-terminus to the C-terminus, as amino acids are added to the carboxyl end of the protein. Chemistry Each amino acid has an amine group and a carboxylic group. Amino acids link to one another by peptide bonds which form through a dehydration reaction that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plasmodium
''Plasmodium'' is a genus of unicellular eukaryotes that are obligate parasites of vertebrates and insects. The life cycles of ''Plasmodium'' species involve development in a blood-feeding insect host which then injects parasites into a vertebrate host during a blood meal. Parasites grow within a vertebrate body tissue (often the liver) before entering the bloodstream to infect red blood cells. The ensuing destruction of host red blood cells can result in malaria. During this infection, some parasites are picked up by a blood-feeding insect (mosquitoes in majority cases), continuing the life cycle. ''Plasmodium'' is a member of the phylum Apicomplexa, a large group of parasitic eukaryotes. Within Apicomplexa, ''Plasmodium'' is in the order Haemosporida and family Plasmodiidae. Over 200 species of ''Plasmodium'' have been described, many of which have been subdivided into 14 subgenera based on parasite morphology and host range. Evolutionary relationships among different ''Pl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trypanosoma Cruzi
''Trypanosoma cruzi'' is a species of parasitic euglenoids. Among the protozoa, the trypanosomes characteristically bore tissue in another organism and feed on blood (primarily) and also lymph. This behaviour causes disease or the likelihood of disease that varies with the organism: Chagas disease in humans, dourine and surra in horses, and a brucellosis-like disease in cattle. Parasites need a host body and the haematophagous insect triatomine (descriptions "assassin bug", "cone-nose bug", and "kissing bug") is the major vector in accord with a mechanism of infection. The triatomine likes the nests of vertebrate animals for shelter, where it bites and sucks blood for food. Individual triatomines infected with protozoa from other contact with animals transmit trypanosomes when the triatomine deposits its faeces on the host's skin surface and then bites. Penetration of the infected faeces is further facilitated by the scratching of the bite area by the human or animal host. Life ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Antiprotozoal Agent
Antiprotozoal agents ( ATC code: ATC P01) is a class of pharmaceuticals used in treatment of protozoan infection. A paraphyletic group, protozoans have little in common with each other. For example, ''Entamoeba histolytica'', a unikont eukaryotic organism, is more closely related to ''Homo sapiens'' (humans), which also belongs to the unikont phylogenetic group, than it is to ''Naegleria fowleri'', a "protozoan" bikont. As a result, agents effective against one pathogen may not be effective against another. Antiprotozoal agents can be grouped by mechanism or by organism. Recent papers have also proposed the use of viruses to treat infections caused by protozoa. Medical uses Antiprotozoals are used to treat protozoal infections, which include amebiasis, giardiasis, cryptosporidiosis, microsporidiosis, malaria, babesiosis, trypanosomiasis, Chagas disease, leishmaniasis, and toxoplasmosis. Currently, many of the treatments for these infections are limited by their toxicity. Outda ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Erythrocytes
Red blood cells (RBCs), also referred to as red cells, red blood corpuscles (in humans or other animals not having nucleus in red blood cells), haematids, erythroid cells or erythrocytes (from Greek ''erythros'' for "red" and ''kytos'' for "hollow vessel", with ''-cyte'' translated as "cell" in modern usage), are the most common type of blood cell and the vertebrate's principal means of delivering oxygen (O2) to the body tissues—via blood flow through the circulatory system. RBCs take up oxygen in the lungs, or in fish the gills, and release it into tissues while squeezing through the body's capillaries. The cytoplasm of a red blood cell is rich in hemoglobin, an iron-containing biomolecule that can bind oxygen and is responsible for the red color of the cells and the blood. Each human red blood cell contains approximately 270 million hemoglobin molecules. The cell membrane is composed of proteins and lipids, and this structure provides properties essential for physiologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-negative Bacteria
Gram-negative bacteria are bacteria that do not retain the crystal violet stain used in the Gram staining method of bacterial differentiation. They are characterized by their cell envelopes, which are composed of a thin peptidoglycan cell wall sandwiched between an inner cytoplasmic cell membrane and a bacterial outer membrane. Gram-negative bacteria are found in virtually all environments on Earth that support life. The gram-negative bacteria include the model organism ''Escherichia coli'', as well as many pathogenic bacteria, such as ''Pseudomonas aeruginosa'', '' Chlamydia trachomatis'', and ''Yersinia pestis''. They are a significant medical challenge as their outer membrane protects them from many antibiotics (including penicillin), detergents that would normally damage the inner cell membrane, and lysozyme, an antimicrobial enzyme produced by animals that forms part of the innate immune system. Additionally, the outer leaflet of this membrane comprises a complex lipopol ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gram-positive Bacteria
In bacteriology, gram-positive bacteria are bacteria that give a positive result in the Gram stain test, which is traditionally used to quickly classify bacteria into two broad categories according to their type of cell wall. Gram-positive bacteria take up the crystal violet stain used in the test, and then appear to be purple-coloured when seen through an optical microscope. This is because the thick peptidoglycan layer in the bacterial cell wall retains the stain after it is washed away from the rest of the sample, in the decolorization stage of the test. Conversely, gram-negative bacteria cannot retain the violet stain after the decolorization step; alcohol used in this stage degrades the outer membrane of gram-negative cells, making the cell wall more porous and incapable of retaining the crystal violet stain. Their peptidoglycan layer is much thinner and sandwiched between an inner cell membrane and a bacterial outer membrane, causing them to take up the counterstain (sa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
