An inexpensive electronic device for measuring electroantennogram responses to sex pheromone components with a voltmeter

ABSTRACT. An inexpensive, portable device which allows measurement of electroantennogram (EAG) maximum amplitudes with a voltmeter instead of an oscilloscope is described. Potential advantages of the device include more rapid recording, low-cost construction of additional EAG recording systems for a laboratory with several users, and portability allowing studies in the field and occasional bench top use. The device is intended for use in conventional EAG recording, where EAG signals with rapid depolarizations are being measured, and where the maximum amplitude of the EAG signal is the only parameter of interest.     

3D-biohybrid systems: applications in drug screening

Biotechnology demands powerful methods for the functional characterisation and monitoring of molecular alterations in tissues in response to various stimuli. Currently, cellular biosensors provide information about cell and tissue internal transduction pathways. In this article, recent biosensor systems are briefly described and the use of 3D tissue aggregates as recognition elements is discussed. An example of an innovative approach for drug testing using 3D heart muscle aggregates, as well as tumor models, positioned in capillary systems for electrical potential recording and impedance measurement is described. The effectiveness of drugs and therapies can be tested and monitored in a short time using such biohybrid sensors.     

Some laboratory methods for recording and displaying temporal patterns of locomotor activity in marine animals

Several methods of recording locomotor activity patterns in marine animals are described. Particular emphasis is given to the use of uniselectors as memory stores and the delivery of stored data periodically to an electric typewriter for display, either numerically or graphically. Actograph design should take into account the normal behaviour of the experimental animals.     

A recording procedure for chronic microelectrodes in the paralyzed cat.

A method is described for repeated recording sessions of cortical thalamic units in the unanaesthetized but paralyzed animal. Because the recording chamber is miniaturized, it is well tolerated by the subject between sessions. The system also permits painless and stable immobilization of the head without the use of earbars, avoiding surgical preparation during the actual recording sessions and allowing long periods of recording. Between sessions the animals always display normal behavior.     

A quantitative method for studying behaviour in small groups of monkeys in captivity

A method is described in which the behaviour of individual animals is recorded to minimise order effects and observer differences in studying a small group of captive monkeys. Gross activity profiles were obtained using time sampling and a modified event recording technique. The application of this simple and relatively unambiguous recording method to the study of social behaviour is indicated.     

A device for evaluation of the dominant component of the EEG activity.

A setup composed of a bioanalyser and additional electronic circuits is described allowing to measure the instantaneous frequency and amplitude of the dominant component of EEG activity. Besides recording the above values on paper by means of the EEG apparatus, functions of probability density of both the amplitude and the frequency of EEG activity are estimated on-line during preadjusted time intervals, and displayed on the screen of the bioanalyser. The mutual relationship between instantaneous EEG amplitude and frequency can be expressed in two-dimensional histograms displayed on a memory scope. The system described is suitable for laboratories having no possibility to use general purpose computer on-line.     

Long-term automatic video recording as a tool for analysing the time patterns of utilisation of predefined locations by wild animals

The design and application of automatic video recording systems for wild animals are described. Such systems enable continuous, long-time and repercussion-free surveillance of selected areas in the field. The performance characteristics of a conventional VHS video-tape system are compared to a digital video recording system. The recordings were used to develop daily and annual plots of occurrence for the different species and to display the preferences for darkness, twilight and light phase by the different species over the year. Absolute utilisation frequency as well as relative species composition can be obtained and compared between seasons or different places. The videos also were analysed for time budgets of basic behaviour patterns like feeding, walking, observing, social interaction, flight and comfort behaviour. Automatic video technique is a highly convenient tool for systematic long-term field research on occurrence of wild animal species, daily and annual activity rhythms, behaviour and area utilisation. Such systems can be applied especially to record animals at clearings, feeding or bait places, water sources, salt licks or traps. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Assessment of methanogenie activity in anaerobic digestion: Apparatus and method

An apparatus is described for the rapid measurement and recording of methanogenic activity in anaerobic fermentations, and its application is demonstrated in the evaluation of the anaerobic contact process, using pear waste. The method is based on recording the rate of manometer liquid displacement in a Warburgtype vessel by means of optical sensors, appropriate electronic circuitry, and an event marking recorder or time-interval printer. Optimum conditions for measuring methanogenic activity included a pH of 6.7–6.9, a final phosphate buffer concentration of 0.07–015M, and formic and acetic acid contents of over 500 and 200 mg/liter, respectively. In comparisons of fermenter liquid and settled effluent, methanogenic activity can be assumed to be proportional to the number of methane formers present. The apparatus should be generally useful in recording rates of gas production or consumption.     

A fluorometric assay for quantitating phenol sulfotransferase activities in homogenates of cells and tissues

A new, rapid, and sensitive method for assaying phenol sulfotransferase activity toward 2-naphthol is described. The product 2-naphthyl sulfate is quantitated fluorometrically. Optimal wavelengths for excitation and emission were determined by recording the three-dimensional fluorescence spectra of the substrate and the product. The new method is applicable to crude cell or tissue homogenates as well as to further purified preparations. A comparison to another widely used method is given to point out the advantages provided by the new procedure. In particular, sensitivity and accuracy of both methods are evaluated and the influence of interfering substances on both systems is compared. These results clearly indicate the superiority of the new method.     

Fabrication and Implantation of Miniature Dual-element Strain Gages for Measuring In Vivo Gastrointestinal Contractions in Rodents.

Gastrointestinal dysfunction remains a major cause of morbidity and mortality. Indeed, gastrointestinal (GI) motility in health and disease remains an area of productive research with over 1,400 published animal studies in just the last 5 years. Numerous techniques have been developed for quantifying smooth muscle activity of the stomach, small intestine, and colon. In vitro and ex vivo techniques offer powerful tools for mechanistic studies of GI function, but outside the context of the integrated systems inherent to an intact organism. Typically, measuring in vivo smooth muscle contractions of the stomach has involved an anesthetized preparation coupled with the introduction of a surgically placed pressure sensor, a static pressure load such as a mildly inflated balloon or by distending the stomach with fluid under barostatically-controlled feedback. Yet many of these approaches present unique disadvantages regarding both the interpretation of results as well as applicability for in vivo use in conscious experimental animal models. The use of dual element strain gages that have been affixed to the serosal surface of the GI tract has offered numerous experimental advantages, which may continue to outweigh the disadvantages. Since these gages are not commercially available, this video presentation provides a detailed, step-by-step guide to the fabrication of the current design of these gages. The strain gage described in this protocol is a design for recording gastric motility in rats. This design has been modified for recording smooth muscle activity along the entire GI tract and requires only subtle variation in the overall fabrication. Representative data from the entire GI tract are included as well as discussion of analysis methods, data interpretation and presentation.     

A Note on a Method for Demonstrating Yeast Catalases after Electrophoresis in Acrylamide Gels

S ummary : A method for demonstrating sites of catalase activity after electrophoresis of yeast cell extracts in acrylamide gel is described. The method yields permanent preparations of catalase patterns and thereby facilitates the recording of results.     

Evaluation of the sustainability of contrasted pig farming systems: breeding programmes

The sustainability of breeding activities in 15 pig farming systems in five European countries was evaluated. One conventional and two differentiated systems per country were studied. The Conventional systems were the standard systems in their countries. The differentiated systems were of three categories: Adapted Conventional with focus on animal welfare, meat quality or environment (five systems); Traditional with local breeds in small-scale production (three systems) and Organic (two systems). Data were collected with a questionnaire from nine breeding organisations providing animals and semen to the studied farming systems and from, on average, five farmers per farming system. The sustainability assessment of breeding activities was performed in four dimensions. The first dimension described whether the market for the product was well defined, and whether the breeding goal reflected the farming system and the farmers’ demands. The second dimension described recording and selection procedures, together with genetic change in traits that were important in the system. The third dimension described genetic variation, both within and between pig breeds. The fourth dimension described the management of the breeding organisation, including communication, transparency, and technical and human resources. The results show substantial differences in the sustainability of breeding activities, both between farming systems within the same category and between different categories of farming systems. The breeding activities are assessed to be more sustainable for conventional systems than for differentiated systems in three of the four dimensions. In most differentiated farming systems, breeding goals are not related to the system, as these systems use the same genetic material as conventional systems. The breeds used in Traditional farming systems are important for genetic biodiversity, but the small scale of these systems renders them vulnerable. It is hoped that, by reflecting on different aspects of sustainability, this study will encourage sustainable developments in pig production.     

Fasciola hepatica: a technique for monitoring in vitro motility

An apparatus utilizing a force and displacement transducer is described for the direct and long-term recording of the motility in vitro of Fasciola hepatica. Normal movement is typically rhythmical, with bursts of more powerful contractions alternating with periods of lesser activity. Such rhythms and the overall level of activity are maintained for more than 30 hr. The fluke remains active for much longer periods of time: recordings of fluke movements have been made for up to 4 days. Potential damage to the fluke caused by the attachment system within the recording apparatus has been determined by the Evans' Blue Technique and scanning electron microscopy. It is restricted to the attachment sites, and does not spread to other parts of the body over the 30-hr normal activity period. Transmission electron microscope studies have shown that the tegument retains its structural and functional integrity over this period of time. There are advantages of the recording apparatus over previous kymographic methods for studying fluke motility.     

Electromagnetic activity in the VLF range and take-off by locusts

The paper discusses insect activity, especially take-off activity in locusts, in relation to weather disturbances. A hypothesis is presented suggesting that atmospheric electromagnetic radiation in the VLF range acts as a take-off stimulus in locusts. A method of recording the spontaneous take-off rate in locusts is described, and two observation series onSchistocerca gregaria are discussed.     

A double-reporter splicing assay for determining splicing efficiency in mammalian cells

Changes in alternative splicing patterns can result from both inherited and acquired defects, and they are increasingly recognized as causes of human diseases. Hence, improvements in the understanding of alternative splicing regulation may provide opportunities for restoring productive patterns of splicing. The identification of factors (such as proteins, nucleic acids or small molecules) that modulate the splicing pattern would be facilitated by systems with which many samples can be screened. The absence of reliable systems prompted us to develop an assay system based on dual enzymatic activities. Two distinct signals derived from spliced and unspliced RNA are measured, providing the basis for a robust, rapid and convenient assay for investigating splicing. This protocol describes how to use this system; the time required for lysing the cells and recording enzymatic activity is about 2 hours.     

Progress in the study of the lichen flora of the British Isles

SEAWARD, M. R. D., 1987. Progress in the study of the lichen flora of the British Isles. Advances in our taxonomic, ecological and geographical knowledge of the lichen flora of the British Isles over the past three centuries are assessed. The growth of literature and the development of field recording are critically surveyed, complemented by numerical and cartographical analyses. The evolution of a comprehensive programme of network recording is described and evaluated. The present and future use of technological advances, particularly in respect of computer databases, is examined.     

Accuracy of the spatial localization of the sources of brain bioelectrical activity in a model homogeneous unrestricted environment

The possibility is considered of use of the model of homogeneous unlimited medium (HUM) for localization of sources of brain bioelectrical activity at recording of electric potentials on its surface. It is shown that when the recording electrodes are arranged in accordance with 10-20 system, the source localization error does not exceed 10% of the head radius practically in any position of the source. A significant dependence is revealed of the source localization error on the concrete electrodes system used in experiment. It demands careful treatment of the available general recommendations on correction of the position of the source found by HUM model without consideration of the concrete arrangement of recording electrodes.     

Schistosoma mansoni: new method for recording motor activity in vitro

A new method for recording the motility of Schistosoma mansoni in vitro is described. Spontaneous activity of the worm shows contraction similar to peristalsis. The worm responded to electrical stimulation with an immediate contraction that was voltage dependent. Oxamniquine produced an increase in the tonus and spontaneous activity of the worm. This method provides a new experimental model for the study of drugs that interfere with Schistosoma mansoni motility.     

Significance of Variability in Archaic Point Assemblages

Abstract

The analysis of a sample of Archaic points from , private collections led the author to question the effectiveness of traditional tool typologies to explain morphological variability. Causes of variations are discussed; time, space and functional specialization are estimated to contribute only part of the total variation. A systems model relating point manufacture and use to hunting strategies is presented. Chipping and retouching techniques are defined as elements of the system variety. Technical choices constitute the mechanisms maintaining the system in a state of equilibrium; technological change results from the introduction of new sets of techniques. The nature of the choices and the range of variations tolerated within the system are deduced from the analysis of the sample. The analysis relies on a recently developed method of recording morphological characteristics. More extensive methods of testing the model are briefly described.