Biosynthesis chitin

Fermentation procedures for preparing uridine 5 -(2-acetamido-2-deoxy-a-D-glucopyranosyl pyrophosphate) have also been reported. One of them255 involves the cultivation of Helminthosporium sativum in the presence of 2-amino-2-deoxy-D-glucose and the antibiotic polyoxin the latter is an inhibitor of chitin biosynthesis. The other256 utilized the incubation of yeast cells with uridine 5 -phosphate in the presence of an excess of 2-amino-2-deoxy-D-glucose and inorganic phosphate.257... 

Insect growth regulation involving such processes as water balance or ecdysis (moulting) are processes that are insect specific but are also fundamental to insect survival. Another is chitin biosynthesis, as chitin is a major component of the insect cuticle. 

Polyoxins are inhibitors of chitin biosynthesis. Chitin is a component of fungal cell walls except in Phycomycete fungi these contain cellulose as their major cell wall constituent, hence polyoxins are inactive against Plasmopara, Pythium and Phytophthora. 

Another group of fungicides interferes with cell wall formation. Two examples of this group include 1) the polyoxines, which prevent chitin formation by competitively inhibiting chitin-synthase, the final enzyme involved in chitin biosynthesis, and 2) melanine biosynthesis inhibitors, especially in Pyricularia oryzae. Examples of... 

Three decades after the first IGRs were introduced in the mid-1970s, new chitin biosynthesis inhibitors, such as noviflumuron (Recruit III ) [190], were developed. Noviflumuron is particularly effective for the control of ants, termites, cockroaches, and fleas. 

Nikkomycins Z 94 and X 95, isolated as nucleoside antibiotics from Streptomyces tendae 221 inhibit chitin biosynthesis and have fungicidal and insecticidal properties. 

Cancer pagurus cuticle can be dispersed in hot, aqueous solutions of lithium thiocyanate and be reprecipitated without separating the chitin and protein components. The stability of the complex under these conditions would suggest the presence of primary bonding. Thus, some ehitin-protein bonding does exist in arthropod cuticle, but its exact nature and its physiological significance or its involvement in chitin biosynthesis (or both) remain uncertain. 

Uridine, 6- (2-acetamido-2-deoxy-n-glu-cosyl dihydrogen pyrophosphate), 208, 210, 211, 262 in chitin biosynthesis, 393... 

Insecticides Affecting Chitin Biosynthesis or Cuticle Sclerotization... 

Etoxazole and flufenoxuron are inhibitors of chitin biosynthesis. Spirodiclofen and spiromesifen are inhibitors of lipid biosynthesis. Spirodiclofen blocks the enzyme acetyl-coenzyme A carboxylase, which allows mites to synthesize important fatty acids. 

Insect cuticle Benzolphenylureas, buprofezin, etoxazole, flufenoxuron Cyromazine Boric acid, silica aerogels Pesticidal soaps Inhibition of chitin biosynthesis Molting disruption Abrasion of cuticle Disruption of cuticle and breakdown of cell membranes... 

Polyoxins polyoxin D (Chitin biosynthesis) 1 Reduced dipeptide pre-mease activity ... 

The mode of action is not clearly defined, but there are indications that it might be connected with cell division, as well as chitin biosynthesis. 

Chitin biosynthesis provides yet another target for drug design. The presence of chitin in membranes of young embryos of Onchocerca gibsoni [81] and the absence... 

The growth of insects can be controlled by the disruption of the molting process by inhibiting chitin biosynthesis [23, 24]. Since the mid-1970s several fluorinated... 

Kakiki et ai. (1969) reported that EBP inhibited the incorporation of glucosamine-into the cell wall of Piricularia orysae. This suggested that a mode of action of this compound might be the inhibition of chitin biosynthesis. According to the experiments of Akatsuka et al. (1977) and of Kodama et al. (1979) the specific inhibition of conversion from phosphatidylethanolamine to phos-phatidylcholin by the transmethylation of S-adenosylmethionine might be one of the modes of action of IBP. 

Chitin biosynthesis starts with the conversion of glucose into A-acetylglucosa-mine-1-phosphate, which requires a series of reactions. The A-acetylglucosamine-... 

A group of aminoacylamino- nucleoside antibiotics (more than 25 components) from cultures of Streptomyces tendae, see also polyoxins. The N. exhibit acar-icidal, insecticidal, and antifungal activities. The activity is based on an inhibition of chitin biosynthesis as a result of the structural analogy to UDP-Al-acetyl-... 

Polyoxins. Peptide nucleosides from cultures of Strep-tomyces species, including S. cacaoi. P. are soluble in water and, although of minor economic significance, are used as fungicides (against Pellicularia sasakii) in rice cultivation in Japan. They act as inhibitors of chitin biosynthesis in fungi. Examples are P. A... 

Inhibitors of chitin biosynthesis, type 1, Homopteran Buprofezin Buprofezin... 

Voltage gated sodium channel (vgSCh) y-aminobutyric add (GABA) receptor/chloride ionophore complex chitin biosynthesis pathways mitochondrial respiratory chain and ryanodine receptor for insedicides. 

Over the past three decades, the N-benzoyl-N -phenyl ureas (BPUs) have been developed and used as commercial IGRs acting by inhibiting chitin biosynthesis... 

The well-known insecticidal benzoyl phenyl ureas (BPUs), exemplified by diflubenzuron, are chitin biosynthesis disrupters, but at an uncharacterized site distinct from chitin synthase (2), Figure 1. The related bridge-cyclized oxazoline chemistries from DuPont and Yashima, represented by etoxazole, are also commercial or near-conunercial insecticides with the same mechanism of action (5), Figure 1. 

TBW larvae characterized by rapid feeding cessation and absence of tarry frass (as seen with the IDDs), with the cuticle not impaired. This unique phenotype was not similar to that produced by juvenile hormone agonists, ecdysone agonists or the chitin biosynthesis disruptor classes represented by the BPUs. 

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