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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, but non-toxic to mice up to 1 μg/20-g mouse. It acts synergistically with oxyopinins of the same venom to increase the insecticidal effect. Both OxyTx1 and OxyTx2 were isolated in 2008 from ''O. linea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurotoxins
Neurotoxins are toxins that are destructive to nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insultsSpencer 2000 that can adversely affect function in both developing and mature nervous tissue.Olney 2002 The term can also be used to classify endogenous compounds, which, when abnormally contacted, can prove neurologically toxic. Though neurotoxins are often neurologically destructive, their ability to specifically target neural components is important in the study of nervous systems. Common examples of neurotoxins include lead, ethanol (drinking alcohol), glutamate,Choi 1987 nitric oxide, botulinum toxin (e.g. Botox), tetanus toxin,Simpson 1986 and tetrodotoxin. Some substances such as nitric oxide and glutamate are in fact essential for proper function of the body and only exert neurotoxic effects at excessive concentrations. Neurotoxins inhibit neuron control over ion concentrations across the cell membrane, or c ... [...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] |
List Of Oxyopidae Species
This page lists all described species of the spider family Oxyopidae accepted by the World Spider Catalog : ''Hamadruas'' ''Hamadruas'' Deeleman-Reinhold, 2009 * '' H. austera'' (Thorell, 1894) — Singapore * '' H. heterosticta'' (Pocock, 1897) — Indonesia (Sulawesi, Moluccas) * '' H. hieroglyphica'' (Thorell, 1887) ( type) — China, Myanmar * '' H. insulana'' (Thorell, 1891) — India (Nicobar Is.) * '' H. pupulus'' (Thorell, 1890) — Indonesia (Nias Is.) * '' H. severa'' (Thorell, 1895) — Myanmar, Indonesia (Lombok) * '' H. signifera'' (Doleschall, 1859) — Indonesia (Java) * '' H. sikkimensis'' (Tikader, 1970) — India, Bangladesh, China * '' H. superba'' (Thorell, 1887) — Myanmar, Thailand, Indonesia (Borneo) ''Hamataliwa'' '' Hamataliwa'' Keyserling, 1887 * '' H. albibarbis'' (Mello-Leitão, 1947) — Brazil * '' H. argyrescens'' Mello-Leitão, 1929 — Brazil * '' H. aurita'' Zhang, Zhu & Song, 2005 — China * '' H. banksi'' (Mello-Leitão, 1928) — Mexico to ... [...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] |
Oxyopes Lineatus
''Oxyopes lineatus'' is a species of spider in the family Oxyopidae, the so-called lynx spiders. They are ambush hunting spiders and do not trap their prey in webs, but subdue their victims with their venomous fangs (chelicerae). They are harmless to humans and larger animals and are not aggressive. Description The body colour of ''Oxyopes lineatus'' is yellowish to light-brown with a pattern of white markings. Like most spiders the species is sexually dimorphic, the males being distinctly smaller than the females. The body length of the adult male is about 4–5 mm, while that of the female is 6–8 mm. They have eight eyes in total, a pair of two large eyes in front and below them a smaller pair. One pair of medium-sized eyes are high up on the side of the head and another pair of large eyes looks above and backward. This combination of eyes gives these spiders an almost 360o view. As in the Oxyopidae in general, there are long spines on their legs in a basket-like ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
Amino Acid Residue
Protein structure is the molecular geometry, three-dimensional arrangement of atoms in an amino acid-chain molecule. Proteins are polymers specifically polypeptides formed from sequences of amino acids, the monomers of the polymer. A single amino acid monomer may also be called a ''residue'' indicating a repeating unit of a polymer. Proteins form by amino acids undergoing condensation reactions, in which the amino acids lose one water molecule per chemical reaction, reaction in order to attach to one another with a peptide bond. By convention, a chain under 30 amino acids is often identified as a peptide, rather than a protein. To be able to perform their biological function, proteins fold into one or more specific spatial conformations driven by a number of non-covalent interactions such as hydrogen bonding, ionic interactions, Van der Waals forces, and hydrophobic packing. To understand the functions of proteins at a molecular level, it is often necessary to determine their Pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disulfide Bridges
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&nbs ... [...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] |
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 consumers. Insecticides are claimed to be a major factor behind the increase in the 20th-century's agricultural productivity. Nearly all insecticides have the potential to significantly alter ecosystems; many are toxic to humans and/or animals; some become concentrated as they spread along the food chain. Insecticides can be classified into two major groups: systemic insecticides, which have residual or long term activity; and contact insecticides, which have no residual activity. The mode of action describes how the pesticide kills or inactivates a pest. It provides another way of classifying insecticides. Mode of action can be important in understanding whether an insecticide will be toxic to unrelated species, such as fish, birds and mammals. Insecticides may be repellent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage Sensitive Calcium Channel
Voltage-gated potassium channels (VGKCs) are transmembrane channels specific for potassium and sensitive to voltage changes in the cell's membrane potential. During action potentials, they play a crucial role in returning the depolarized cell to a resting state. Classification Alpha subunits Alpha subunits form the actual conductance pore. Based on sequence homology of the hydrophobic transmembrane cores, the alpha subunits of voltage-gated potassium channels are grouped into 12 classes. These are labeled Kvα1-12. The following is a list of the 40 known human voltage-gated potassium channel alpha subunits grouped first according to function and then subgrouped according to the Kv sequence homology classification scheme: Delayed rectifier slowly inactivating or non-inactivating *Kvα1.x - Shaker-related: Kv1.1 (KCNA1), Kv1.2 (KCNA2), Kv1.3 (KCNA3), Kv1.5 (KCNA5), Kv1.6 (KCNA6), Kv1.7 ( KCNA7), Kv1.8 (KCNA10) *Kvα2.x - Shab-related: Kv2.1 (KCNB1), Kv2.2 (KCNB2) *Kvα3.x - ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spodoptera Litura
''Spodoptera litura'', otherwise known as the tobacco cutworm or cotton leafworm, is a nocturnal moth in the family Noctuidae. ''S. litura'' is a serious polyphagous pest in Asia, Oceania, and the Indian subcontinent that was first described by Johan Christian Fabricius in 1775. Its common names reference two of the most frequent host plants of the moth. In total, 87 species of host plants that are infested by ''S. litura'' are of economic importance. The species parasitize the plants through the larvae vigorous eating patterns, oftentimes leaving the leaves completely destroyed. The moth's effects are quite disastrous, destroying economically important agricultural crops and decreasing yield in some plants completely. Their potential impact on the many different cultivated crops, and subsequently the local agricultural economy, has led to serious efforts to control the pests. ''S. litura'' is often confused with its close relative, ''Spodoptera littoralis''. These two species ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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