Wildlife of China "ciwei" or the "thorned creature". Porcupines are rodents and hedgehogs belong to a separate order. Three species of Old World porcupine are found in China: the Asiatic brush-tailed porcupine, Indian crested porcupine, and Malayan porcupine. Many parts of the porcupine including the brain, organs, fat, quills and even the feces can be used to make traditional Chinese medicine. Porcupines are raised on farms. In the early 20th century, the Eurasian beaver was hunted to near extinction for its fur and castoreum, a scent gland secretion used to make perfume and medicine. Though the global population has rebounded, the animal remains
Extracellular polymeric substance Extracellular polymeric substance Extracellular polymeric substances (EPSs) are natural polymers of high molecular weight secreted by microorganisms into their environment. EPSs establish the functional and structural integrity of biofilms, and are considered the fundamental component that determines the physiochemical properties of a biofilm. EPSs are mostly composed of polysaccharides (exopolysaccharides) and proteins, but include other macro-molecules such as DNA, lipids and humic substances. EPSs are the construction material of bacterial settlements and either remain attached to the cell's outer surface, or are secreted into its growth medium. These compounds are important in biofilm formation and cells attachment to surfaces. EPSs