Highly accurate synthesis of the fully 2′-fluoro-modified oligonucleotide by Therminator DNA polymerases

Oligonucleotides composed of natural nucleotides are inapplicable for biotechnical and therapeutic use due to its instability under biological conditions. Therminator DNA polymerases, mutant DNA polymerases of thermophilic marine archaea, show that they can efficiently synthesize fully 2′-fluoro-modified (2′F-) oligonucleotides. Furthermore, the sequence analysis reveals that the oligonucleotide sequence is highly accurate, especially the fidelity of a 2′F-oligonucleotide synthesized by Therminator II is more accurate than that of natural RNA synthesized by conventional RNA polymerase. These finding would be helpful for the synthesis of chemically modified oligonucleotides, for the use of biotechnical or medical applications.     

Fuels and industrial chemicals through biotechnology. 2

An overview of research on the biotechnical production of fuels and industrial chemicals during the two-year period of 1983-1984 is presented. Ethanol fermentation has continued to be the subject of major interest. A considerable amount of work has been directed to alternative feedstocks such as pentose sugars and lactose, and to bacterial fermentations. Reports on extrusion cooking as a continuous pretreatment method for subsequent ethanol fermentation, and on novel alternative downstream processing techniques have been published. In addition to ethanol fermentation, much attention has been paid to the biotechnical production of 2,3-butanediol, and of a number of organic and amino acids. In general, there appears to be a growing interest in the application of biocatalysis for the production of specialty chemicals, although only a few examples will be discussed in this paper. The construction of a demonstration plant to produce ethanol from molasses by a two 10 kL bed-volume immobilized yeast bioreactors at the Kyowa Hakko Kogyo Company Hofu plant, the announcement by Nitto Chemical Industries Company to begin the biotechnical production of acrylamide, and the French decision to construct pilot plants for the biotechnical production of acetone-butanol-ethanol cosolvent and of ethanol from renewable resources represent major scale-up developments.     

Statistische analyse eines nichtlinearen systems mit mehreren eingängen durch optimale linearisierung

As compared to linear systems for which well-proven standardised procedures exist, the analysis of nonlinear systems based on random signals cannot be handled in a similar manner because of the lack of a nonlinear systems theory. A number of different procedures has been published, the most popular of them based on the application of the Volterra series, but also procedures based on the optimal linearisation of a given nonlinearity. This paper applies the procedure of optimal linearisation to a system with several imputs and one output. It is possible to extend the procedure to systems having several outputs. As an example, the parameters of the coupling function of a one-stage nerve-network will be computed. The practicability of the procedure and associated errors will be investigated.

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Der Autor dankt Herrn Prof. Dr.-Ing. W. v. Seelen, Universität Mainz für wertvolle Diskussionen und die kritische durchsicht des Manuskripts     

Informationsverarbeitung in homogenen Netzen von Neuronenmodellen

Summary The interconnection structures of the peripheral part of the nervous system, which are considered here, are two-dimensional homogeneous networks with time and space dependent inputs and outputs. The principles of connection under consideration comprise lateral inhibition and facilitation. The transfer functions of those linear networks as well as the stability problem are investigated on a digital computer using different system parameters. A closed form solution is given for an infinitely large element density which describes the network properties. In this case an inhibition system acts as high pass filter on the spatial frequencies of the input, whereas a facilitation network acts as low pass filter. The properties of the networks and the transformations in case of moving patterns are analysed using the methods of systems theory.

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Auszug aus einer Dissertation an der Fakultät für Maschinenwesen der Technischen Universität Hannover, Institut für Theoretische Elektrotechnik (Prof. Dr.-Ing. habil. H. Tischner).

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Herrn Prof. Dr.-Ing. habil. H. Tischner danke ich für die Anregung zu dieser Arbeit und seine ständige Unterstützung. Mein Dank gilt ferner der Firma Brown, Boveri & Cie. AG, Mannheim, für die finanzielle Förderung. Den Mitarbeitern im Institut für Schwingungsforschung, insbesondere Herrn Direktor Dr.-Ing. A. Schief bin ich für wertvolle Diskussionen verpflichtet.     

A construction of pooling designs with some happy surprises.

The screening of data sets for "positive data objects" is essential to modern technology. A (group) test that indicates whether a positive data object is in a specific subset or pool of the dataset can greatly facilitate the identification of all the positive data objects. A collection of tested pools is called a pooling design. Pooling designs are standard experimental tools in many biotechnical applications. In this paper, we use the (linear) subspace relation coupled with the general concept of a "containment matrix" to construct pooling designs with surprisingly high degrees of error correction (detection.) Error-correcting pooling designs are important to biotechnical applications where error rates often are as high as 15%. What is also surprising is that the rank of the pooling design containment matrix is independent of the number of positive data objects in the dataset.     

On identification of separable kernel systems

An identification procedure for special separable kernel systems is presented. The suitable definition of adequateness of a signal leads to a systematic treatment of the choice of inputs for identification.This work was supported by the Stiftung Volkswagenwerk grant number II/35 111. Prof. Dr.-Ing. W. v. Seelen was in charge of the project     

Pollenanalytische Untersuchungen zur Frage der natürlichen Waldgrenze und des natürlichen Fichtenanteils im Stuhleckgebiet (Fischbacher Alpen)

Ohne ZusammenfassungDie Anregung zur vorliegenden Arbeit verdanke ich Herrn Prof. Dr.Hannes Mayer. Bei der Probengewinnung unterstützte mich Herr Dipl.-Ing. Dr.Kurt Zukrigl, der mich auf die beiden Moore hinwies und mir auch Angaben über die gegenwärtigen Bewaldungsverhältnisse — zum Teil auf Grund seiner noch unveröffentlichten Vegetationsaufnahmen — in dankenswerter Weise zur Verfügung stellte.     

A chemical method for investigating disulfide-coupled peptide and protein folding

Investigations of protein folding have largely involved studies using disulfide-containing proteins, as disulfide-coupled folding of proteins permits the folding intermediates to be trapped and their conformations determined. Over the last decade, a combination of new biotechnical and chemical methodology has resulted in a remarkable acceleration in our understanding of the mechanism of disulfide-coupled protein folding. In particular, expressed protein ligation, a combination of native chemical ligation and an intein-based approach, permits specifically labeled proteins to be easily produced for studies of protein folding using biophysical methods, such as NMR spectroscopy and X-ray crystallography. A method for regio-selective formation of disulfide bonds using chemical procedures has also been established. This strategy is particularly relevant for the study of disulfide-coupled protein folding, and provides us not only with the native conformation, but also the kinetically trapped topological isomer with native disulfide bonds. Here we review recent developments and applications of biotechnical and chemical methods to investigations of disulfide-coupled peptide and protein folding. Chemical additives designed to accelerate correct protein folding and to avoid non-specific aggregation are also discussed.     

Über die Erkennungszeit beim Lesen

Ohne ZusammenfassungDiese Arbeit wurde unter der Leitung von Herrn Prof. Dr.-Ing. E. h. K. Kupfmüller durchgeführt, dem ich für Hinweise und Anregungen herzlich danke. Besonderer Dank gebührt der Akademie der Wissenschaften und der Literatur, Mainz, für die gewährte finanzielle Unterstützung.     

反义肽及其在生化分离中的应用

反义肽是由反义RNA编码和翻译的肽．它可与其正义肽分子发生专一性相互作用．近年反义肽的这种特异性结合实例研究,已为其在生化分离领域应用奠定了基础,尤其是在色谱亲和配基的选择方面,可以预见不久以反义肽为配基的亲和色谱将是生物工程产品分离的一种有效手段．     

Tangential flow microfiltration and ultrafiltration for human influenza A virus concentration and purification

Large scale purification of viruses and viral vectors for gene therapy applications and viral vaccines is a major separation challenge. Here tangential flow microfiltration and ultrafiltration using flat sheet membranes has been investigated for concentration of human influenza A virus. Ultrafiltration membranes with molecular weight cutoffs of 100 and 300 kDa as well as 0.1, 0.2 and 0.45 microm microfiltration membranes have been tested. The results indicate that use of 300 kDa membranes not only concentrate the virus particles but also lead to a significant removal of host cell proteins and DNA in the permeate. Tangential flow filtration may be used to fractionate virus particles. Human influenza A virus particles are spherical with an average size of 100 nm. Use of a 0.1 microm membrane leads to passage of virus particles less than 100 nm into the permeate and an increase of larger particles in the retentate. These results suggest that control of the transmembrane pressure, membrane pore size and pore size distribution could enable isolation of intact virus particles from damaged virions. Isolation of the virus particles of interest from viral fragments and other particulate matter could result in simplification of subsequent purification steps. Larger pore size membranes such as 0.45 microm that allow the passage of all virus particles may be used to remove host cell fragments. In addition virus particles attached to these fragments will be removed. Careful selection of membrane morphology and operating conditions will be essential in order to maximize the benefit of tangential flow filtration steps in the purification of viral products from cell cultures.     

Epitope‐specificity of recombinant antibodies reveals promiscuous peptide‐binding properties

Protein–peptide interactions are a common occurrence and essential for numerous cellular processes, and frequently explored in broad applications within biology, medicine, and proteomics. Therefore, understanding the molecular mechanism(s) of protein–peptide recognition, specificity, and binding interactions will be essential. In this study, we report the first detailed analysis of antibody–peptide interaction characteristics, by combining large‐scale experimental peptide binding data with the structural analysis of eight human recombinant antibodies and numerous peptides, targeting tryptic mammalian and eukaryote proteomes. The results consistently revealed that promiscuous peptide‐binding interactions, that is, both specific and degenerate binding, were exhibited by all antibodies, and the discovery was corroborated by orthogonal data, indicating that this might be a general phenomenon for low‐affinity antibody–peptide interactions. The molecular mechanism for the degenerate peptide‐binding specificity appeared to be executed through the use of 2–3 semi‐conserved anchor residues in the C‐terminal part of the peptides, in analogue to the mechanism utilized by the major histocompatibility complex–peptide complexes. In the long‐term, this knowledge will be instrumental for advancing our fundamental understanding of protein–peptide interactions, as well as for designing, generating, and applying peptide specific antibodies, or peptide‐binding proteins in general, in various biotechnical and medical applications.     

Review of computational fluid dynamics applications in biotechnology processes

Computational fluid dynamics (CFD) is well established as a tool of choice for solving problems that involve one or more of the following phenomena: flow of fluids, heat transfer,mass transfer, and chemical reaction. Unit operations that are commonly utilized in biotechnology processes are often complex and as such would greatly benefit from application of CFD. The thirst for deeper process and product understanding that has arisen out of initiatives such as quality by design provides further impetus toward usefulness of CFD for problems that may otherwise require extensive experimentation. Not surprisingly, there has been increasing interest in applying CFD toward a variety of applications in biotechnology processing in the last decade. In this article, we will review applications in the major unit operations involved with processing of biotechnology products. These include fermentation,centrifugation, chromatography, ultrafiltration, microfiltration, and freeze drying. We feel that the future applications of CFD in biotechnology processing will focus on establishing CFD as a tool of choice for providing process understanding that can be then used to guide more efficient and effective experimentation. This article puts special emphasis on the work done in the last 10 years.     

Microbial biofilms in biotechnological processes

This review summarizes the information concerning the following applications of microbial biofilms in biotechnology: the biodegradation of organic substances and other contaminants during wastewater treatment, biosynthesis, and biocatalysis. The main types of reactors for implementing biotechnical processes based on microbial biofilms are discussed. The advantages and drawbacks of biocatalysts in the form of microbial biofilms for the biotransformation of organic substances are examined.     

New tools for the genetic manipulation of filamentous fungi

Filamentous fungi have a long-standing tradition as industrial producers of primary and secondary metabolites. Initially, industrial scientists selected production strains from natural isolates that fulfilled both microbiological and technical requirements for economical production processes. Subsequently, genetically modified strains with novel properties were obtained through traditional strain improvement programs relying mostly on random mutagenesis. In recent years, however, recombinant technologies have contributed significantly to improve the capacities of production and have also allowed the design of genetically manipulated strains. These major advances were only made possible by basic research bringing deeper and novel insights into cellular and molecular fungal processes, thus allowing the design of genetically manipulated strains. This better understanding of fundamental genetic processes in model organisms has resulted in the design and generation of new experimental transformation strategies to manipulate specifically gene expression and function in diverse filamentous fungi, including those having a biotechnical significance. In this review, we summarize recent developments in the application of homologous DNA recombination and RNA interference to manipulate fungal recipients for further improvement of physiology and development in regards to biotechnical and pharmaceutical applications.     

Processing visual signals with nonlinear spatial filters

Summary The properties of nonlinear spatial filters as a major part of the peripheral nervous system are investigated with respect to processing of two types of signals: a deterministic stepfunction and Gaussian noise. The nonlinearity of the nerve cell is treated as a threshold element. It is shown that certain unfavorable characteristics of linear filters do not occur in such nonlinear filters. The basic nonlinear effects of combined space-time-filtering are demonstrated by using bandpass filters.Time- and space-dependent noise is applied to the nonlinear bandpass. The two subsystems formed by the linear bandpass section and the threshold are treated separately.Two examples for the application of nonlinear spatial filtering are given.This paper contains results of a thesis submitted to the Fachbereich Biologie der Johannes Gutenberg-Universität, Mainz, in partial fulfillment of the requirements for the degree of a Dr. rer. nat.The author is grateful to Prof. Dr.-Ing. W. v. Seelen for his continual guidance and support.     

Frustrated by lack of job opportunities in Canada,MD moves to US space-medicine program

A Canadian physician-engineer who had difficulty finding suitable work in Canada is now employed by an American company that is helping develop the medical systems that will serve astronauts. Dr. Douglas Hamilton thinks research in space medicine will have applications on earth.     

Über ein Äquivalenzgesetz für Intervalle akustischer Empfindungsgrö\en

Summary Psychoacoustic experiments are reported in which the subjects had to state which one of two aural sensations had been varied predominantly. The sensations investigated are loudness, pitch and roughness of amplitude modulated tones. Proper analysis of the subjects' responses results in those intervals of these three sensations that are equivalent to each other. The results can be uniformly described by a simple law which means that equivalent intervals of sensations include the same number of just noticeable differences of each sensation.

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Herrn Prof. Dr.-Ing. E. Zwicker sei für die Anregung dieser Untersuchungen sowie für ihre Förderung durch wertvolle Hinweise herzlicher Dank ausgesprochen. Die Untersuchungen wurden durch die Deutsche Forschungsgemeinschaft unterstüzt.     

Nonhuman primates and teratological research

Nonhuman primates were first recognized as models for the study of developmental toxicity (teratology) following the thalidomide tragedy. Since that time they have played important roles in both testing of drugs for human safety and as models for studying specific malformations commonly seen in children. Although in vitro and alternative test systems using lower animal forms or simplified test systems have been incorporated into developmental toxicity studies, whole animal testing will be required for the foreseeable future because of the complex relationship of the maternal/embryofetal/placental unit. The nonhuman primate will be particularly valuable where equivocal results are experienced in other commonly used laboratory species, when the drug/chemical is likely to be used during pregnancy, and for human-derived biotechnical products which often are not bioactive in nonprimate species.     

代谢工程在核黄素生产上的应用

核黄素(维生素B2)为天然水溶性的B族维生素,是维持机体代谢所必须的营养物质。目前核黄素的工业化生产主要有微生物发酵法和化学半合成法两种,其中微生物发酵法以生产工艺简单、原料廉价、环境友好以及资源可再生等优点而倍受世界核黄素生产商的青睐。代谢工程是近二十年来发展起来的新型学科,主要利用分子生物学技术对细胞进行遗传修饰,从而改进产物生成或细胞特性。为进一步提高核黄素产量,通过代谢工程手段构建出了核黄素高产菌株,其中尤以枯草芽孢杆菌最为成功。要得到较高的核黄素产率,必须保证碳架、能量等价物以及氧化还原辅(酶)因子在细胞代谢过程中处于适当的比率。以枯草芽孢杆菌进行核黄素生产为例,主要从增强碳源和能源利用效率、增强核黄素生物合成途径代谢流以及解除核黄素生物合成过程中的反馈调节方面综述了代谢工程在指导核黄素生产方面的应用,并讨论了其未来的发展方向。