Sugar sensitivity

Different from the situation on the labellum (see later), not all tarsal sensilla contain a sugar-sensitive sensory neuron (Meunier et al. 2000). Also, the response spectra of the tarsal sensory neurons differ from those of labellar sensilla. That is, labellar contact chemosensory neurons are classically called S, W, LI or L2 neurons (Ishimoto and Tanimura. 2004), on the basis of their electrophysiological response spectra. The L neurons are activated by salt, in the case of LI with a low threshold (typically no electrophysiological responses are seen for concentrations below 10 mM Fujishiro et al. 1984) and in the case of L2 neurons with a high threshold L2 neurons can in some cases also be activated by bitter compounds. 

Silver IA, Erecinska M. 1998. Glucose-induced intracellular ion changes in sugar-sensitive hypothalamic neurons. J Neurophysiol 79 1733-1745. 

It is this compound which breaks down into alcohol and carbon dioxide and regenerates the sodium phosphate. The latter can then again combine repeatedly with the sugar, sensitizing it to the breaking down action of the enzyme until the fermentation is complete. It has been shown by careful experiments that during the period of increased fermentation the amounts of alcohol and carbon dioxide produced are stcrchimetrically related to the... 

You can see why complex carbs are so much better for your moods. They re also better for your brain, which much prefers to get a relatively constant supply of glucose. So switching from refined to complex carbs will immediately help you to feel calmer, fuller, and more in control of your appetite—especially if you re sugar-sensitive. 

Restrict your intake of refined sugar to 10 percent or less of your total calories. If you re sugar-sensitive, consider entirely eliminating sugar and refined carbohydrates (white rice and foods made from white flour, including most breads, pastas, and processed foods). 

Receptor cells sensitive to host plant compounds that stimulate feeding have also been identified in several species of Yponomeuta moths. Y. cagnagellus feeding on Euonymus has one dulcitol (sugar)-sensitive cell in the medial and one in the lateral sensillum styloconicum (van Drongelen, 1979,1980). Another species, Y. evonymellus, is also stimulated by dulcitol at the sensory and behavioral level even though the compound does not occur in its host plant. This contradictory result may be explained by the possible presence of dulcitol in an ancestral host plant (van Drongelen, 1979,1980). 

Mitchell, B. K. and Gregory, P. (1979) Physiology of the maxillary sugar sensitive cell in the red turnip beetle, Entomoscelis americana, J, comp. Physiol, 132, 167-78. 

B. (2004) Thermoresponsive properties of sugar sensitive copolymer of N-isopropylacrylamide and... 

Formation of silver mirror or precipitate of silver indicates reducing agent. (This is often a more sensitive test than I (a) above, and some compounds reduce ammoniacal silver nitrate but are without effect on Fehling s solution.) Given by aldehydes and chloral hydrate formates, lactates and tartrates reducing sugars benzoquinone many amines uric acid. 

Hydrogen chloride in air can also be a phytotoxicant (88). Tomatoes, sugar beets, and fmit trees of the Pmnus family are sensitive to HCl in air. Exposure of concentrated hydrochloric acid to the skin can cause chemical bums or dermatitis. Whereas the irritation is noticed readily, the acid can be water flushed from the exposed area. Copious use of miming water is the only recommended safety procedure for any external exposure. Ingestion is seldom a problem because hydrochloric acid is a normal constituent of the stomach juices. If significant quantities are accidentally swallowed, it can be neutrali2ed by antacids. 

Sucrose quantitation has also been performed by colorimetric methods. However, in recent years, automated enzymatic analyzers and instmmental methods (eg, ion chromatography and hplc) have become increasingly popular, as they provide greater sensitivity and accuracy. Near infrared (nir) spectroscopy is currendy under evaluation as a tool for sucrose quantitation in sugar mills and food processing operations. 

Colorimetric Methods. Numerous colorimetric methods exist for the quantitative determination of carbohydrates as a group (8). Among the most popular of these is the phenol—sulfuric acid method of Dubois (9), which rehes on the color formed when a carbohydrate reacts with phenol in the presence of hot sulfuric acid. The test is sensitive for virtually all classes of carbohydrates. Colorimetric methods are usually employed when a very small concentration of carbohydrate is present, and are often used in clinical situations. The Somogyi method, of which there are many variations, rehes on the reduction of cupric sulfate to cuprous oxide and is appHcable to reducing sugars. 

The system shown is heavily used in food processing applications such as milk or chocolate crumb production, sugar substitutes, modified starch, and alginates. In addition to food processing applications, such a system is used in the processing of heat-sensitive pharmaceuticals, polymer suspensions like latex, in processing pigments and dyestuffs, and pesticides. 

Note The reagent can be employed on cellulose layers. Sodium acetate-buffered kieselguhr layers are less suitable [6]. Only a few sugars are detectable and those with lower sensitivity if acid is not added to the reagent [7]. 

When used at room temperature in the presence of an active platinum catalyst in an inert solvent, e.g., acetone or ethyl acetate, oxygen will oxidize nonhindered, saturated hydroxyl groups and exposed allylic alcohols. This reagent has found extensive use in sugar chemistry and is particularly suited for the selective oxidation of either 3a- or 3j -alcohols of steroids. Other hydroxyl groups on the steroid skeleton are much less sensitive to oxidation. As a result, this reaction has been used extensively in research on polyhydroxy cardiac-active principles, e.g., the cardenolides and bufadienolides, where the 3-hydroxyl group is easily oxidized without extensive oxidation or dehydration of other hydroxyl groups. The ordinarily difficult selective oxidation of the... 

This is the basis of the very sensitive Fehling s test for sugars and other reducing agents. A solution of a copper(H) salt dissolved in alkaline tartrate solution is added to the substance in question. If this is a reducing agent then a characteristic red precipitate is produced. 

When carbon tetrabromide is used, the alkyl bromide is formed. Providing moisture is excluded from the reaction mixture (HX is formed otherwise), the reaction conditions are completely neutral, affording a convenient preparation of the halides of acid-sensitive substrates (for example, sugars). 

---