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Oxyopinin
Oxyopinins are a group of peptide toxins present in the venom of lynx spiders belonging to the genus ''Oxyopes'', from which they derive their name. Properties Oxyopinins have antimicrobial, haemolytic, and insecticidal activities. They are the largest linear cationic amphipathic peptides detected in the venom of any spider. They are structurally α-helical peptides. Subtypes The first five peptides, namely oxyopinins 1, 2a, 2b, 2c, and 2d, were described in 2002 from ''Oxyopes kitabensis''. Oxyopinin 1 is composed of 48 amino acid residues, with a molecular mass of 5221.2 Da. It has significant amino acid sequence similarity to other venoms of other animals. For example, it has 20% sequence similarity with the ant insecticidal peptide ponericinL2. It is also 29% identical to the amino acid residues of the frog antimicrobial peptide dermaseptin. Oxyopinins 2a, 2b, 2c, and 2d (originally designated oxyopinins 2, 3, 4, and 5 respectively) are very similar in their sequences. At le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxytoxin
Oxotoxins, or oxytoxins, are a group of neurotoxins present in the venom of lynx spiders belonging to the genus ''Oxyopes'', hence the name ''oxytoxin''. They are disulfide-rich peptides. Only two types are so far reported from two different species, the larger oxytoxin 1 (OxyTx1) from ''Oxyopes kitabensis'', and the smaller oxytoxin 2 (OxyTx2) from ''Oxyopes lineatus''. OxyTx1, the first known oxytoxin, was discovered in 2002. It was found to enhance the lethal efficacy of the spider venom by acting together with oxyopinins. It is composed of 69 amino acid residue, which are cross-linked by five disulfide bridges. It is a large peptide having a molecular mass of 8059.2 Da; but shows the size of 9,109.4 Da due to the presence of disulfide bridges. It is a potent insecticide Insecticides are substances used to kill insects. They include ovicides and larvicides used against insect eggs and larvae, respectively. Insecticides are used in agriculture, medicine, industry and by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxyopes Takobius
''Oxyopes takobius'' is a species of spiders in the genus ''Oxyopes'' of the lynx spider family, Oxyopidae. The species was first described in 1969, and is found from Central Asia to China. Its venom contains a peptide toxin called oxyopinin Oxyopinins are a group of peptide toxins present in the venom of lynx spiders belonging to the genus ''Oxyopes'', from which they derive their name. Properties Oxyopinins have antimicrobial, haemolytic, and insecticidal activities. They are the lar ... (oxyopinin 4a), which was discovered in 2002. This species has been misidentified in pharmacological research as "''Oxyopes kitabensis''."''Venom Composition and Strategies in Spiders: Is Everything Possible?,'' Lucia Kuhn-Nentwig, Reto Stocklin, and Wolfgang Nentwig, Table 2, page 9, collected in References External linksInformation at Encyclopedia of Life [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxyopes Kitabensis
''Oxyopes takobius'' is a species of spiders in the genus ''Oxyopes'' of the lynx spider family, Oxyopidae. The species was first described in 1969, and is found from Central Asia to China. Its venom contains a peptide toxin called oxyopinin (oxyopinin 4a), which was discovered in 2002. This species has been misidentified in pharmacological research as "''Oxyopes kitabensis''."''Venom Composition and Strategies in Spiders: Is Everything Possible?,'' Lucia Kuhn-Nentwig, Reto Stocklin, and Wolfgang Nentwig, Table 2, page 9, collected in References External linksInformation at Encyclopedia of Life Oxyopidae Spiders of Asia Spiders described in 1969 {{Araneomorphae-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lynx Spider
Lynx spider (Oxyopidae) is a family of araneomorph spiders first described by Tamerlan Thorell in 1870. Most species make little use of webs, instead spending their lives as hunting spiders on plants. Many species frequent flowers in particular, ambushing pollinators, much as crab spiders do. They tend to tolerate members of their own species more than most spiders do, and at least one species has been identified as exhibiting social behaviour. Description There are several genera of Oxyopidae and they differ in their habits and adaptations. Most of them have large spiny bristles on their legs and in many species the bristles form almost a basket-like structure that may assist in confining the prey that they grasp, and protect the spider from its struggles. Most ''Oxyopes'' and ''Hamataliwa'' species are small to medium in size. Lynx spiders, in spite of being largely ambush hunters, are very speedy runners and leapers, alert and with good vision. Oxyopidae in general rely on kee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphatidylcholine
Phosphatidylcholines (PC) are a class of phospholipids that incorporate choline as a headgroup. They are a major component of biological membranes and can be easily obtained from a variety of readily available sources, such as egg yolk or soybeans, from which they are mechanically or chemically extracted using hexane. They are also a member of the lecithin group of yellow-brownish fatty substances occurring in animal and plant tissues. Dipalmitoyl phosphatidylcholine (a.k.a. lecithin) is a major component of pulmonary surfactant and is often used in the L/S ratio to calculate fetal lung maturity. While phosphatidylcholines are found in all plant and animal cells, they are absent in the membranes of most bacteria, including ''Escherichia coli''. Purified phosphatidylcholine is produced commercially. The name ''lecithin'' was derived from Greek λέκιθος, ''lekithos'' 'egg yolk' by Theodore Nicolas Gobley, a French chemist and pharmacist of the mid-19th century, who appli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxyopidae
Lynx spider (Oxyopidae) is a family of araneomorph spiders first described by Tamerlan Thorell in 1870. Most species make little use of webs, instead spending their lives as hunting spiders on plants. Many species frequent flowers in particular, ambushing pollinators, much as crab spiders do. They tend to tolerate members of their own species more than most spiders do, and at least one species has been identified as exhibiting social behaviour. Description There are several genera of Oxyopidae and they differ in their habits and adaptations. Most of them have large spiny bristles on their legs and in many species the bristles form almost a basket-like structure that may assist in confining the prey that they grasp, and protect the spider from its struggles. Most '' Oxyopes'' and '' Hamataliwa'' species are small to medium in size. Lynx spiders, in spite of being largely ambush hunters, are very speedy runners and leapers, alert and with good vision. Oxyopidae in general rely on k ... [...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] |
Disulfide Bond
In biochemistry, a disulfide (or disulphide in British English) refers to a functional group with the structure . The linkage is also called an SS-bond or sometimes a disulfide bridge and is usually derived by the coupling of two thiol groups. In biology, disulfide bridges formed between thiol groups in two cysteine residues are an important component of the secondary and tertiary structure of proteins. ''Persulfide'' usually refers to compounds. In inorganic chemistry disulfide usually refers to the corresponding anion (−S−S−). Organic disulfides Symmetrical disulfides are compounds of the formula . Most disulfides encountered in organo sulfur chemistry are symmetrical disulfides. Unsymmetrical disulfides (also called heterodisulfides) are compounds of the formula . They are less common in organic chemistry, but most disulfides in nature are unsymmetrical. Properties The disulfide bonds are strong, with a typical bond dissociation energy of 60 kcal/mol (251& ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dalton (unit)
The dalton or unified atomic mass unit (symbols: Da or u) is a non-SI unit of mass widely used in physics and chemistry. It is defined as of the mass of an unbound neutral atom of carbon-12 in its nuclear and electronic ground state and at rest. The atomic mass constant, denoted ''m''u, is defined identically, giving . This unit is commonly used in physics and chemistry to express the mass of atomic-scale objects, such as atoms, molecules, and elementary particles, both for discrete instances and multiple types of ensemble averages. For example, an atom of helium-4 has a mass of . This is an intrinsic property of the isotope and all helium-4 atoms have the same mass. Acetylsalicylic acid (aspirin), , has an average mass of approximately . However, there are no acetylsalicylic acid molecules with this mass. The two most common masses of individual acetylsalicylic acid molecules are , having the most common isotopes, and , in which one carbon is carbon-13. The molecular mass ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dermaseptin
Dermaseptins are a family of peptides isolated from skin of the frog genus ''Phyllomedusa''. The sequence of the dermaseptins varies greatly but due to the presence of lysine residues all are cationic and most have the potential to form amphipathic helices in water or when integrated with the lipid bilayer of the bacterial membrane. Clear separation of two lobes of positive and negative intramolecular electrostatic potential is thought to be important in cytotoxic activity. Dermaseptins are typically 27-34 amino acid residues in length and were the first vertebrate peptides demonstrated as having a lethal effect on the filamentous fungi implicated in severe opportunistic infections accompanying immunodeficiency syndrome and immunosuppressive drug therapy. Dermaseptin use in a novel drug delivery system has been proposed. The system is based on the affinity of dermaseptins for the plasma membrane of human erythrocytes. After transient loading of the cells with the non-toxic der ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oxyopes
''Oxyopes'' is a genus of lynx spiders found worldwide. It includes arounds 300 species and is classified under the lynx spider family Oxyopidae. Like other lynx spiders, they are easily recognizable by the six larger eyes arranged hexagonally on top of the head (prosoma), with the remaining smaller two eyes in front. They are also characterized by long spine-like bristles (setae) on their legs. They are ambush predators, actively hunting prey by sight. Though they produce and use silk, they do not build webs to capture prey. The genus was first established in 1804 by the French zoologist Pierre André Latreille. The generic name means "keen-eyed", from Ancient Greek ὀξύς (''oxús'', "sharp") and ὤψ (''ṓps'', "eye"). Species Species classified under ''Oxyopes'' (including subspecies) and their distribution ranges are the following: * '' Oxyopes abebae'' Strand, 1906 — Ethiopia, East Africa * '' Oxyopes acleistus'' Chamberlin, 1929 — USA, Mexico * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha Helical
The alpha helix (α-helix) is a common motif in the secondary structure of proteins and is a right hand-helix conformation in which every backbone N−H group hydrogen bonds to the backbone C=O group of the amino acid located four residues earlier along the protein sequence. The alpha helix is also called a classic Pauling–Corey–Branson α-helix. The name 3.613-helix is also used for this type of helix, denoting the average number of residues per helical turn, with 13 atoms being involved in the ring formed by the hydrogen bond. Among types of local structure in proteins, the α-helix is the most extreme and the most predictable from sequence, as well as the most prevalent. Discovery In the early 1930s, William Astbury showed that there were drastic changes in the X-ray fiber diffraction of moist wool or hair fibers upon significant stretching. The data suggested that the unstretched fibers had a coiled molecular structure with a characteristic repeat of ≈. Astbur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
