Polypeptide growth factors and angiogenesis.

Angiogenesis is the term used to describe the formation and development of blood vessels. The renewed interest in regulation and mechanistic aspects of angiogenesis depends on advances in the comprehension of metastatic dissemination of cancers, ischaemic heart disease and blood-brain barrier formation. Recently, many poly-peptide growth factors have been discovered which regulate the angiogenic process, most of them are stimulators and few inhibitors have been described. There is some evidence that many polypeptide growth factors employ prostanoids as second messengers. If this evidence will be extended to angiogenic factors, it will be possible to use inhibitors of prostaglandin H synthase and/or prostanoid receptor blockers in the control of tumour induced angiogenesis.     

Polypeptide nature of growth requirement in yeast extract for Thermoplasma acidophilum.

The active component(s) in yeast extract required by Thermoplasma acidophilum for growth is polypeptide in nature. A fraction from yeast extract was isolated and partially characterized as one or more peptides of molecular weight about 1,000 containing 8 to 10 amino acids. Although it was composed largely of basic and dicarboxylic amino acids, only one amino group per molecule was free. The polypeptide(s) appeared to bind avidly to cations. No other organic compounds except glucose were needed by Thermoplasma. Among several hundred known compounds tested, only glutathione plus Fe2+ or Fe3+, clostridial ferredoxin, and spinach ferredoxin elicited any growth response.     

Polypeptide growth factors in embryogenesis and tumor growth

Polypeptide growth factors, which belong to different families (epidermal growth factors, insulin-like growth factors, fibroblast growth factors, transforming growth factors-beta, and some others), were characterized regarding their specific role in embryogenesis and tumor growth. Differences and parallels of the functioning of growth factors in these processes have been noted. Potential significance of the described characteristics of growth factors for directed modulation of embryogenesis and tumor growth is discussed.     

Polypeptide growth factors in animal embryogenesis

Data about polypeptide growth factors in animal cells during embryogenesis and about the sensitivity of these cells to regulatory effect of the factors have been systematically reviewed. The conclusion was drawn that they play an important role in molecular mechanisms controlling cell proliferation and differentiation at the early embryonic stages. Information has also been provided about transforming growth factors and about the products of some proto-oncogenes, which are detected in the embryonic cells in amounts comparable with those in the transformed cells. However, this does not lead to malignant growth. Moreover, microenvironment of an intact embryo exerts an antitransforming influence on tumor cells. Studies of the "normalizing" effect of the embryonic cells may help in developing new methods of suppression of the malignant growth.     

Environmental biotechnology for sustainability.

In the post-industrial society, waste management is integrated in the concepts of responsibility, reliability and continuity. Therefore industry and public office are obliged to implement the concepts of structured environmental management systems more and more strictly. The endpoints are dependent on the type of wastes and on the priorities set by society. They will with time evolve towards more restriction of all kinds of emissions. This will require increasing inputs of labour, information technology and energy into waste treatment and overall waste management. Particularly for aqueous and gaseous wastes that are not contained, continuously improving treatment with maximum re-use and minimum dissipation in the ecosphere will be the trend of the future. Moreover, the public in general and the individual citizen in particular will request to have (bio)assays to monitor regularly and autonomously the quality of his environment. Such advanced waste management requires considerable energy input. It thus may come in conflict with current concerns about CO2-emissions and the Kyoto agreements. Innovative approaches to combine waste management and the International Climate Change Partnership (ICCP) directives, for instance by implementing biological carbon sequestration, are therefore warranted. Biotechnology has a major role to play particularly in terms of advanced treatment down to ng/l-levels and in terms of validating the quality of the environment by means of powerful and intelligent bio-monitoring devices.     

The greening of biotechnology: the growth of the US biotechnology industry

The growth and advancement of biotechnology worldwide has been the focus of many studies, and at the heart of this advancement has been a new industry of small biotechnology firms in the United States. Since the early 1970s more than 300 small companies have been founded in the United States to work with the new technologies of genetic engineering, monoclonal antibody production, and in related areas. In addition, many major corporations in the United States have sought entry into biotechnology. Hundreds of new companies have been founded to interact with the biotechnology firms and large corporations, supplying reagents, equipment, fermentation expertise and serving a variety of other ancillary functions. Nowhere else in the world has a biotechnology industry been initiated to such a large degree. Today, the average US biotechnology firm is six to seven years old. The current state of the US biotechnology industry, historical perspectives, major trends and some future outlooks will be described below.     

Polypeptide growth factors in gastroenteropancreatic neuroendocrine tumours

Polypeptide growth factors form a potent class of extracellular signal molecules in the regulation of cellular differentiation and proliferation. Disturbances in the expression of growth factors influence the normal pathway of differentiation and lead to cellular transformation and tumour progression. Contemporary medical studies report that various growth factors such as those for platelet-derived growth factor, vascular endothelial growth factor, epidermal growth factor, hepatocyte growth factor and insulin-like growth factor are expressed in gastroenteropancreatic neuroendocrine tumours (GEP/NET). Polypeptide growth factors have great significance in the growth, progression and development of metastases by various tumours. We describe the role of growth factors in GEP/NET on the basis of the available reports of medical research.     

Chemical biotechnology pharmaceutical biotechnology. Web alert

A selection of World Wide Web sites relevant to papers published in this issue of Current Opinion in Biotechnology.     

Stereochemical Criteria for Polypeptide and Protein Chain Conformations: III. Helical and Hydrogen-Bonded Polypeptide Chains

The previous study, for a pair of peptide units, of the conformations which are allowed on the basis of stereochemical criteria of van der Waals contacts has been extended to the analysis of possible conformations of helical polypeptide chains. Computer methods have been developed which select conformations on the basis of both satisfactory interatomic contacts as well as the formation of good intramolecular hydrogen bonds. Such programs have been used to map the allowed dihedral angle pairs (varphi, psi) for helical polypeptide chains. This survey has been made for values of the N-C(a)-C' angle (tau) of 105 degrees , 110 degrees , and 115 degrees , from which the significant influence of this angle in determining allowed helical conformations can be demonstrated. Calculations have also been carried out using potential energy functions for the interaction between nonbonded atoms. The potential energy contour maps obtained in this manner are basically similar to the conformational maps calculated by the first method.