Schon vor Einzug der Gentechnik wurden zahlreiche Enzyme industriell genutzt. Allerdings machen lediglich wenige Dutzend Enzyme über 90 % der industriellen Enzymnutzung aus. Einige der bekanntesten Beispiele sind in Tabelle 11.1 aufgelistet. Der Einsatz dieser Proteine erfolgt unter relativ rauen, oxidierenden Bedingungen, wie sie in lebenden Zellen nicht herrschen. Infolgedessen sind gerade diese Proteine außergewöhnlich robust und stabil und in dieser Hinsicht keineswegs repräsentativ für typische Enzyme. Auffallenderweise handelt es sich bei den meisten davon um Hydrolasen, die entweder Kohlenhydratpolymere oder Proteine abbauen.
Stem cells have ignited controversy among groups of politicians, religious leaders, and many people in the public. Whether scientists should study stem cells is hotly debated in the United States, but other parts of the world are also creating rules and regulations as to the use and study of stem cells. Many of the reports seen in the media provide a very negative slant to the use of stem cells in scientific research, but most of the reports do not explain the reason stem cells are so controversial. In addition, most of the accounts do not explain what a stem cell is and why scientists want to study them. One of the key goals for this chapter is to provide the answers to these questions and to describe the importance these cells have in your tissues and organs. Because of the key role stem cells play in our body, the idea of using stem cells to cure diseases and disabilities has evolved. This chapter explains the motive and current state of research for the use of stem cells in some therapies. Most importantly, the chapter distinguishes between the types of stem cells that are the focus of the heated political debates and the other types of stem cells, and the continuum of characteristics that range between these types of cells.
Biotechnology involves the use of living organisms in industrial processes—particularly in agriculture, food processing, and medicine. Biotechnology has been around ever since humans began manipulating the natural environment to improve their food supply, housing, and health. Biotechnology is not limited to humankind. Beavers cut up trees to build homes. Elephants deliberately drink fermented fruit to get an alcohol buzz. People have been making wine, beer, cheese, and bread for centuries. For wine, the earliest evidence of wine production has been dated to c. 6000 BC. All these processes rely on microorganisms to modify the original ingredients. Ever since the beginning of human civilization, farmers have chosen higher yielding crops by trial and error, so that many modern crop plants have much larger fruit or seeds than their ancestors.
Zwei wichtige Eigenschaften von lebenden Organismen sind die Reproduktion ihres eigenen Genoms und ein eigener Energiestoffwechsel. Um dieses bewerkstelligen zu können, muss ein Organismus auf der Basis der in seiner DNA codierten Information selbst Proteine synthetisieren. Proteine sind für den Aufbau der Zelle, die ihr die Gestalt und die Struktur verleihen, essenziell. Zu den Proteinen zählen auch Enzyme, die Reaktionen des Energiestoffwechsels katalysieren, und sie regulieren zelluläre Prozesse wie die Replikation. Proteine bilden membrandurchspannende Kanäle und stellen so die Kommunikation und den Austausch von Stoffwechselmetaboliten zwischen den Zellen sicher. Die Proteinsynthese ist einer der wichtigsten Prozesse in allen lebenden Organismen.
Proteomics has opened the door to identify more and more clinically relevant proteins. Once identified, these proteins need to be studied in detail, including expression of the protein in model organisms by using recombinant DNA techniques. Some proteins will become therapeutic agents, and large amounts of purified protein will be required.
The environment around us has always been a source of new products and stimulated our imagination in developing new technologies. Our species is very successful at harnessing the environment for our benefit. We are also good at destroying or harming the environment for immediate gains. The readily visible world has been charted and mapped, but areas under the ocean and in the deep recesses of jungles are still unknown. In fact, many parts of the visible world still harbor unknown life forms invisible to the naked eye, including bacteria and viruses. These are found in the air, water, and land. Many have unique metabolisms, and some have abilities never seen before. Many can live in extreme environments once thought too hot or too dry for life to exist.
