Mammals boron

Boron is an essential trace element for plants, and may well turn out to be essential for mammals as well. The boron-containing polyether-macrolide antibiotic, boromycin, was isolated as a potent anti-HIV agent. 

No requirement for boron in mammals is proven, although evidence is accumulating suggesting that boron may be an essential nutrient. Boron is related to normal energy utilization, immune function, and metabolism of bone, minerals, and lipids (Penland 1998). Boron deficiency (<0.04... 

Table 29.9 Lethal and Sublethal Effects of Boron on Mammals...

Boron Unknown, but essential for green afeae and higher plants probably essential ultratrace element in animals/ Moderately toxic to plants Slightly toxic to mammals. ... 

No requirement for boron in mammals is proven, although evidence is accumulating suggesting that boron may be an essential nutrient. Boron is related to normal energy utilization, immune function, and metabolism of bone, minerals, and lipids. Boron deficiency (<0.04 mg B/kg ration of dams) impairs early embryonic development in rodents these effects were not observed at 2.0 mg B/kg ration. Boron deprivation in animals and humans results in decreased brain electrical activity similar to that observed in nonspecific malnutrition, and reduced cognitive and psychomotor function. Learning performance (manual dexterity, eye-hand coordination, memory, attention, perception) in humans was... 

In mammals, excessive boron consumption results in a reduced growth rate and sometimes loss in body weight these may not be entirely due to reduced feed and water consumption. Growth retardation has been reported in cattle given 150.0 mg B/L drinking water (about... 

Non-metallic trace nutrients include boron (for plants only), iodine and fluorine (for vertebrates), selenium, and silicon. Selenium forms an essential part of the important mammalian enzyme glutathione peroxidase which, in mammals, protects membranes from oxidation and is one of the microbiocidal enzymes in phagocytes (Stadtman, 1980). A selenium, iron, and molybdenum enzyme was described above under molybdenum . Silicon is thought to contribute to the architecture and resiliance of connective tissues of vertebrates. In rats, silicon is essential for growth and development. It seems to be present as a silanolate, with Si-O-R bridges to such polysaccharides as heparin and hyaluronic acid (Schwarz, 1973). 

Nevertheless, current knowledge of biochemical systems and synthetic techniques may allow us to explore them from a slightly different perspective. Namely, what would life look like with an expanded genetic code—that is, with additional amino acids added into the proteins of life. Indeed, over the past few years chemists have been able to utilize native biochemical systems as well as evolved tRNA molecules (which we will discuss in Chapter 25) to load many unique amino acids into proteins of interest at any specific point desired in a number of different cells, including those of yeast, some mammals, and bacteria like E. coli. Some of the unnatural amino acids are shown below. They include ones with unique metals (like selenium), reactive functional groups (such as a ketone and an azide) that can be used for additional chemistry, and a boronic acid that can be used to bind certain sugars covalently. These synthetic amino acids are all derivatives of phenylalanine, but many other amino acid parent structures can be used as well. 

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