Predicting evolutionary potential. I. Predicting the evolution of a lactose-PTS system in Escherichia coli.

Genomes contain not only information for current biological functions, but also information for potential novel functions that may allow the host to adapt to new environments. The field of experimental evolution studies that potential by selecting for novel functions and deducing the means by which the function evolved, but until now it has not attempted to predict the outcomes of such experiments. Here I present a model system that is being developed specifically to examine the issue of what kind of information is most useful in predicting how novel functions will evolve. The system is the evolution of a Lac-PTS transport system and a phospho-beta-galactosidase hydrolase system as a novel pathway for metabolism of lactose in Escherichia coli. Two kinds of information, sequence-based phylogenetic inference and biochemical activity, are considered as predictors of which E. coli genes will evolve the required new functions. Both biochemical data and phylogenetic inference predict that the cryptic celABC genes, which currently specify a PTS-beta-glucoside transport system, are most likely to evolve into a PTS-lactose transport system. Phylogenetic inference predicts that the bglA gene, which currently specifies a phospho-beta-glucosidase, is most likely to evolve into a phospho-beta-galactosidase. In contrast, biochemical data predict that the cryptic bglB gene, which also currently specifies a phospho-beta-glucosidase, is most likely to evolve into a phospho-beta-galactosidase.     

Rigorous and extended application of information theory to the afferent visual system of the cat. I. Basic concepts

Information theory is applied to data from microelectrode recordings of the cat's afferent visual system in a manner more general than hitherto usual. It is shown that it is not necessary to know the particular neuronal code for information calculations by taking the signal itself as the symbols. Uncontrollable errors thus can be avoided. It is further shown that by this approach the dynamical behaviour of the system is fully considered for information transfer. Quantities are defined to exhibit the time course of transmitted information.     

Synchronous and asynchronous brain-state-in-a-box information system neural models.

Synchronous and asynchronous information system neural models are proposed that are hybrids of Pawlak's information system and Brain-State-in-a-Box (BSB) neural models. The stability of the proposed models is studied using LaSalle's Invariance Principle. Applications to an analysis of the United Nations activities are presented as examples.     

Integration of a barcode reader with a commercial flow cytometer.

This report describes the application and installation of a barcode reader on a standard EPICS Elite flow cytometer. The barcode reader system eliminates keyboard entry of sample information on the cytometer. The system automates the transfer of sample information already present in our laboratory database to the cytometer at run time. The system uses a standard "off-the-shelf" bar code wand with a personal computer keyboard interface and requires no additional software at run time. No typing of sample information is required by the operator at any stage of normal sample operation at the cytometer. All operations are automatically coded into the cytometry software using the macro functions of the software. Tubes are inserted into the tube reader and sample information is transferred automatically into the cytometer. We have found that the system allows rapid and continuous operation of routine clinical and research samples. This automated data entry also reduces the possibility of data input errors.     

Comparative study of the stomatogastric system of the decapod crustacea. II. Musculature

The stomach musculature of several species of decapod Crustacea is described in detail. All species are sufficiently similar so that muscle homologies can be established. The Natantia have a simplified muscle system while the Reptantia are characterized by a more complex muscle system. Species can be arranged in a graded series of muscle system complexity which closely follows the evolution of the decapod Crustacea. The information presented here should provide the basis for consistent identification of the stomatogastric motor neurons throughout the decapod Crustacea.     

Organization of voluntary movement.

There have recently been a number of advances in our knowledge of the organization of complex, multi-joint movements. Promising starts have been made in our understanding of how the motor system translates information about the location of external targets into motor commands encoded in a body-based coordinate system. Two simplifying strategies for trajectory control that are discussed are parallel specification of response features and the programming of equilibrium trajectories. New insights have also been gained into how neural systems process sensory information to plan and assist with task performance. A number of recent papers emphasize the feedforward use of sensory input, which is mediated through models of the external world, the body's physical plant, and the task structure. These models exert their influence at both reflex and higher levels and permit the preparation of predictive default parameters of trajectories as well as strategies for resolving task demands.     

Development of an academic Internet resource.

Networked electronic publication is a relatively new development that has already begun to change the way in which medical information is exchanged. Electronic publications can present ideas that would be impossible in printed text, using multimedia components such as sound and movies. Physicians who use the World Wide Web (WWW) on a regular basis may recognize the value of electronic publication and decide to become information providers. Nearly anyone with a computer and modem can create a WWW resource on a Web server at a hospital or on a commercial hosting service. Medical publication on the Internet demands a high level of quality control because the information will be available to anyone who cares to look. Creating a peer-review system for electronic information may, therefore, help to enhance academic recognition of Internet medical resources. Resources containing medical information must be continually available and protected from system failures and unauthorized access. As Internet technology matures and these problems are solved, electronic publication may become the predominant method of communication between medical professionals.     

Examination of the Distinctive Awards System.

When they stopped secrecy, the consultants of an internationally-famous postgraduate teaching centre in psychiatry--not a designated teaching hospital--discovered that they had one-tenth the national average of distinction awards. Subsequent investigation of the whole system suggests that this is not an isolated case. Moreover, official figures are scanty and misleading. This paper explores the difficulties in understanding, investigating, and influencing the system. The composition of the committees involved, the de facto quota system, the method of collecting information, and the convention of secrecy are examined and critized.     

Information processing immunogenetic analysis. IV. Information amount and predictive power of different immunogenetic models.

Principles of information theory are imposed on immunogenetic information processing, whereby the 'information amount', simplicity, 'redundancy' and 'predicatability' of different encodings, models, theories or mappings can be objectively compared. As an example, the experimental observables emanating from the Rh system at its 10 reagent-8 haplotype level is shown to obtain an information amount of 140,120 and 78 bits when interpreted (encoded according to a simple-complex, complex-simple and complex-complex theory, model or program, respectively. The 'predictive' or 'accomodating' power of the simple-complex and complex-simple theories is shown to be 134, respectively 366 bits for a given set of experimental observables emanating from a S3 universe.     

The knowledge base of the oculomotor system.

In everyday life, eye movements enable the eyes to gather the information required for motor actions. They are thus proactive, anticipating actions rather than just responding to stimuli. This means that the oculomotor system needs to know where to look and what to look for. Using examples from table tennis, driving and music reading we show that the information the eye movement system requires is very varied in origin and highly task specific, and it is suggested that the control program or schema for a particular action must include directions for the oculomotor and visual processing systems. In many activities (reading text and music, typing, steering) processed information is held in a memory buffer for a period of about a second. This permits a match between the discontinuous input from the eyes and continuous motor output, and in particular allows the eyes to be involved in more than one task.     

Neural coding of gustatory information.

The nervous system encodes information relating chemical stimuli to taste perception, beginning with transduction mechanisms at the receptor and ending in the representation of stimulus attributes by the activity of neurons in the brain. Recent studies have rekindled the long-standing debate about whether taste information is coded by the pattern of activity across afferent neurons or by specifically tuned 'labeled lines'. Taste neurons are broadly tuned to stimuli representing different qualities and are also responsive to stimulus intensity and often to touch and temperature. Their responsiveness is also modulated by a number of physiological factors. In addition to representing stimulus quality and intensity, activity in taste neurons must code information about the hedonic value of gustatory stimuli. These considerations suggest that individual gustatory neurons contribute to the coding of more than one stimulus parameter, making the response of any one cell meaningful only in the context of the activity of its neighbors.     

The status of online Mendelian inheritance in man (OMIM) medio 1994.

During the last year many changes have been introduced into the system of maintaining OMIM. There are three major components of the reorganization. First, a distributed editorial system was introduced which provides a three-tiered editorial board with senior editors, science writers and subject editors. Second, MIM entries have been restructured to provide separate gene and phenotype information and to organize them into separate catalogs. The restructuring also establishes clearly defined sections for entering new information, converts old entries to the new structure, and establishes a file maintenance and editorial system in SGML format. Third, the entry numbering and naming system has been modified. In addition, the information has been made available through a variety of output media, including books, CD-ROM and online access based on the IRx, WAIS, Gopher and WWW formats.     

Sorting of proteins to the vacuoles of plant cells.

The secretory system of plant cells sorts a large number of soluble proteins that either are secreted or accumulate in vacuoles. Secretion is a bulk-flow process that requires no information beyond the presence of a signal peptide necessary to enter the endoplasmic reticulum. Many vacuolar proteins are glycoproteins and the glycans are often modified as the proteins pass through the Golgi complex. Vacuolar targeting information is not contained in glycans as it is in animal cells; rather, targeting information is in polypeptide domains as it is in yeast cells. Several such domains have now been identified, but these show little or no amino acid sequence homology. We discuss the possibilities that targeting of protein to plant vacuoles may involve receptors as well as aggregation of protein at low pH.     

Nutrient tasting and signaling mechanisms in the gut. IV. There is more to taste than meets the tongue

The tongue is the principal organ that provides sensory information about the quality and quantity of chemicals in food. Other information about the temperature and texture of food is also transduced on the tongue, via extragemmal receptors that form branches of the trigeminal, glossopharyngeal, and vagal nerves. These systems, together with information from the gastrointestinal (GI) system, interact to determine whether or not food is palatable. In this themes article, emphasis is placed on the integrative aspects of gustatory processing by showing the convergence of gustatory information with somatosensory, nociceptive, and visceral information (from the GI system) on the tongue and in the brain. Our thesis is that gustation should be thought of as an integral part of a distributed, interacting multimodal system in which information from other systems, including the GI system, can modulate the taste of food.     

Cloning simulation in the cage environment.

The CAGE/GEM(TM) software toolkit for genetic engineering is briefly described. The system functionally uses color graphics and is menu driven. It integrates genetics and features information ("Overlays") with information based on sequence analysis ("Representations"). The system is structured around CAD (Computer Aided Design) principles. The CAGE (Computer Aided Genetic Engineering) aspects of the software are emphasized and illustrated by a simulated cloning of the hepatitis B core antigen gene into the BAMHI site of plasmid pBR322.     

Informational aspects of telepathology in routine surgical pathology.

Application of computer and telecommunication technology calls serious challenges in routine diagnostic pathology. Complete data integration, fast access patients' data to usage of diagnosis thesaurus labeled with standardized codes and free text supplements, complex inquiry of the data contents, data exchange via teleconsultation and multilevel data protection are required functions of an integrated information system. Increasing requirement for teleconsultation transferring a large amount of multimedia data among different pathology information systems raises new questions in telepathology. Creation of complex telematic systems in pathology requires efficient methods of software engineering and implementation. Information technology of object-oriented modeling, usage of client server architecture and relational database management systems enables more compatible systems in field of telepathology. The aim of this paper is to present a practical example how to unify text based database, image archive and teleconsultation in a frame of an integrated telematic system and to discuss the main conceptual questions of information technology of telepathology.     

Computer evaluation of reference limits.

Reference limits are necessary for medical laboratory to provide objective information on health in concrete characteristics. With respect to changeability of some factors influencing upon homeostasis, reference limits must be determined and redetermined in each clinical laboratory with the high degree of the internal quality control system. The presented program computing reference limits and providing expert consultations facilitates solution.     

Analysis of complex physiological systems by information flow: a time scale-specific complexity assessment.

In the last two decades conventional linear methods for biosignal analysis have been substantially extended by non-stationary, non-linear, and complexity approaches. So far, complexity is usually assessed with regard to one single time scale, disregarding complex physiology organised on different time scales. This shortcoming was overcome and medically evaluated by information flow functions developed in our research group in collaboration with several theoretical, experimental, and clinical partners. In the present work, the information flow is introduced and typical information flow characteristics are demonstrated. The prognostic value of autonomic information flow (AIF), which reflects communication in the cardiovascular system, was shown in patients with multiple organ dysfunction syndrome and in patients with heart failure. Gait information flow (GIF), which reflects communication in the motor control system during walking, was introduced to discriminate between controls and elderly patients suffering from low back pain. The applications presented for the theoretically based approach of information flow confirm its value for the identification of complex physiological systems. The medical relevance has to be confirmed by comprehensive clinical studies. These information flow measures substantially extend the established linear and complexity measures in biosignal analysis.     

Medical data base system with an ability of automated diagnosis.

We carried out an experiment on a medical information system in which a clinical data base is combined organically with computer programs for automated diagnosis. In this system, the parameters for automated diagnosis are devised to be renewed as the contents of the data base (patient's information) increase. This system can be regarded as a data base possessing a kind of diagnosing ability which grows up with time. We have named this system "Intelligent Data Base". The algorithm for computer diagnosis used in this study is based on maximum likelihood method, and each likelihood is weighted with a prior probability of each disease. The discrimination efficiency of this method is logically equal to that of the Bayes rule. First 27 cases were learnt by the system and correct diagnosis was obtained in 78% of the cases. When cases for learning increased to 82, the percentage of correct diagnosis was improved to 95%.