Arthropods muscles

This dual activity against both nematode and arthropod parasites of animals was an unexpected bonus from a screen for anthelmintic agents. The reason for this broad activity lies in their mode of action. They act by interfering with y-aminobutyric acid (GABA) mediated neurotransmission. When treated with avermectin, the nematode Ascaris suum becomes paralyzed although it retains normal muscle tone (17). Picrotoxin, an antagonist of GABA, can reverse the effect of avermectin on neurotransmission vitro. 

Typhus fever B (Rickeffsia prowazekii) Insects— arthropods (primarily human lice) animals— flying squirrels in the US typically has been seen 1-2 weeb, typically 12 days No (but infected lice can be transferred) Standa d High fever, rash (w/in 6 days), muscle pain, hypotension, photophobia, delirium Typically 2 weeks in untreated pts hat recover Doxycycline, chloramphenicol... 

Avermectins are a group of closely related compounds isolated from the fungus Streptomyces avermitilis that are used to control the parasites of humans and animals, as well as arthropod pests in crops. They have fairly high mammalian toxicity, but their movement into treated leaves, oral activity against insect pests, and rapid breakdown in sunlight are all favorable properties. In insects and worms poisoned by avermectin, inactivity and flaccid paralysis occur from its relaxing effect on muscles. 

In mammals, 25% of the protein in the body is collagen it provides the scaffold that holds the entire body together. Movement is provided almost entirely by interactions of actin with myosin (making muscle) or of kinesin/dynein with microtubules (see also Chapter 21). Few animal materials have the chemical stability of cellulose probably only chitin (primarily in arthropods and fungi, but also part of the metabolic pathway of other animals including man) and elastin. 

The case of hemerythrin (see, for example, Stenkamp, 1994 Kurtz, 1999) is of particular interest for several reasons. It is clearly distinct from the other hemo-respiratory proteins and also occurs as analogous blood and muscle types (see, for example, Takagi and Cox, 1991). Intriguingly, its occurrence in animals (specifically the brachiopods, sipunculans, priapulids, and a number of annelids) makes no phylogenetic sense in terms of our current understanding of metazoan relationships. This is most obvious in terms of the placement of the priapulids in the ecdysozoans (i.e. related to arthropods), whereas the other three phyla are all lophotrochozoans. Even within this latter superclade, the distribution of hemerythrin does not seem to be phylogenetically informative. 

Avermectin Bia has been shown to stimulate chloride ion uptake into cockroach muscle ( 140 and block transmission at the arthropod neuromuscular junction by increasing GABA-mediated chloride ion permeability (15), (16). To extend our understanding of ion channel types present in the surface membrane of the synaptosome we examined the effects of ivermectin (22,23-dihydroavermectin B.) and some closely related milbemycins. Both ivermectin and the milbemycins examined, with the exception of milbemycin a9, were... 

The synapses using acetylcholine (ACh) as the transmitter substance are the target for a wide variety of pesticides and therefore need a more detailed description. Acetylcholine is used as a transmitter substance in nearly all animal phyla, but at different parts of the nervous system. It is also present in single-cell animals and even in plants. Enzymes that catalyze the hydrolysis of acetylcholine, the cholinesterases, are also present in various organisms not having a nervous system. In insects and other arthropods, ACh is the transmitter of messages from sensory neurons to the central nervous system (CNS) and within the CNS, but not from motor neurons to skeletal muscles, where the transmitter is glutamate. In annelids, the excitatory transmitter for the body wall muscles is acetylcholine, as at the neuromuscular junctions in vertebrates. 

Biological Weapon - An item of material that projects, disperses, or disseminates a biological agent including arthropod vectors. Blepharospasm - Uncontrollable winking caused by involuntary contraction of an eyelid muscle. BLPS - Ballistic / Laser Eye protection. Bradycardia - Abnormally slow heartbeat. Broken Arrows - An accident involving nuclear weapons. While it is almost impossible for the warhead to accidentally detonate, the accident may spread radioactive contamination over a wide area. 

Transmission of nervous impulses by way of acetylcholine release and action is widespread, occurring not only in higher animals but also important in arthropods. In higher animals acetylcholine is the most important neurohormonal transmitter. It functions in the autonomic system, in motor nerves, and in some parts of the central nervous system. It functions not only in synapses between neurons but also on muscles or glands that are controlled by the neurons. After its action the acetylcholine is removed rapidly through hydrolysis by the enzyme acetylcholine esterase. Drugs, including some alkaloids, can interact with this process at several levels ... 

Several antiparasitic drugs enhance GABA neurotransmission in nematodes and arthropods and cause muscle paralysis. These drugs include piperazirre, milbemycins, and avermectins (eg, ivermectirr). The answer is (B). 

The simplest mechanoreceptors are morphologically undifferentiated nerve endings found in the connective tissue of skin. In many mechanoreceptors there have evolved accessory structures whose function is the efficient conversion of mechanical energy to electrical energy in the receptor cell. Examples are Pacinian corpuscles, in which the sensitive ending is covered by a cap-sule, muscle stretch receptors, in which the mechanically sensitive endings are associated with specialized muscle fibers, and the hair-like sensilla in the exoskeletons of arthropods (Figure 45). Elaborated accessory structures used to detect and analyze sound waves are found in the vertebrate middle and inner ear. ... 

Budd, G.E. (1998) Arthropod body-plan evolution in the Cambrian with an example from anomalocaridid muscle , Lethaia, 31, 197-210. 

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