Responses to the change in the environment in pairs of male rats genetically selected for activity level

Laboratory Wistar strain rats were genetically selected for high (+A) and low (-A) activity level. In thirteen pairs of adult males of the 23rd filial generation reactions to changes in the external environment were studied. The animals were housed in breeding cages four each. Two parallel studies were conducted: in pairs simultaneously placed into a novel environment (NOV), empty cages of the same dimensions as the home cage (HC), in the second, behaviour of the second pair that remained in the HC, after removal of two cage-mates, was tested. Once a minute, for a period of one hour, the type of activity was recorded and noted whether it was an element effected in contact with the partner or without any contact. The animals +A and -A differed in the frequency of various types of activity and immobility, in the ratio between behavioural manifestations shown in or without contact as well as in the response to the type of modified environment. To changes in the situation, whether removed cage-mates from the HC or placed into NOV +A animals reacted with a high wave of environment exploration which gradually habituated. -A rats equally responded with exploration but on a lower level. In +rats we recorded more frequently exploration without contact with the partner in HC and NOV in comparison with -A, more frequent grooming, less immobility in contact and with no contact. Between +A partners there was a greater number of contacts in NOV than in HC whereas in the -A group the incidence of contact did not differ between HC and NOV. ANOVA revealed the influence of factors of genetics and environment and interaction in several behavioural categories. The simple and in time economical method demonstrated the possibility of use for the detection of differences between +A and -A lines even at relatively small changes in the external stimulatory situation.     

Improving housing conditions for laboratory mice: a review of "environmental enrichment"

Laboratory animal facilities have been designed to provide a standard environment where animals can be kept in good physical health at the same time as economic and ergonomic considerations are met. Recognizing the potential welfare problem associated with behavioural restriction in such housing systems, a number of attempts have been made to improve this environment, generally described under the term "environmental enrichment". Modifications of cages for mice usually consist of providing material for nest building and structures which can serve as hiding places and/or for climbing. We have reviewed 40 studies carried out between 1987 and 2000, in which preferences as well as the effect of housing modifications have been studied. Mice will work for access to nesting material and make use of this material to make nests in which they rest. They prefer a more complex cage to the standard cage and will also work for access to cages with shelter and raised platforms. On the basis of present knowledge, it is recommended that mice should have access to nesting material. Strategies for future research are outlined in the article.     

Cage enrichment with paper tissue, but not plastic tunnels, increases variability in mouse model of asthma

Environmental enrichment, besides having a great impact on animal welfare, can also be a potential variable in experimental research. Thus, we investigated whether enrichment of cages with paper tissues or plastic tunnels affects scientific outcome in the well-described mouse model of allergic asthma. BALB/cJ mice were introduced to paper tissues as nesting material, transparent plastic tunnels serving as shelters or kept in non-enriched cages. Afterwards, mice were sensitized to chicken egg ovalbumin (OVA) precipitated in aluminium sulphate and then intranasally challenged with OVA to induce allergic lung inflammation. Mice housed in cages enriched with paper tissues, but not with plastic tunnels, had increased total cell number, eosinophil number and IL-13 concentration in bronchoalveolar lavage fluid in comparison with the non-enriched control group. These results indicate that the effect of environmental enrichment on mice asthma models depends on the type of enrichment used. Therefore, it is important to consider the potential effects of any environmental enrichment on animal welfare and more importantly, on research results in order to standardize and obtain more accurate data from rodent studies.     

Levitation and movement of human tumor cells using a printed circuit board device based on software-controlled dielectrophoresis

In this study we describe an original, efficient, and innovative printed circuit board (PCB) device able to generate dielectrophoresis-based, software-controlled cages that can be moved to any place inside a microchamber. Depending on their dielectrophoretic properties, eukaryotic cells can be "entrapped" in cages and moved under software control. The main conclusion gathered from the experimental data reported is that the PCB device based on dielectrophoresis permits levitation and movement of different tumor cells at different dielectrophoresis conditions. The results presented herein are therefore the basis for experiments aimed at forced interactions or separation of eukaryotic cells using "lab-on-a-chip." In fact, because many cages can be controlled at the same time, and two or more cages can be forced to share the same or a different location, it is possible, in principle, either to bring in contact cells of a differing histotype or to separate them.     

Monte Carlo Simulations of Proteins in Cages: Influence of Confinement on the Stability of Intermediate States

We study the folding of small proteins inside confining potentials. Proteins are described using an effective potential model that contains the Ramachandran angles as degrees of freedom and does not need any a priori information about the native state. Hydrogen bonds, dipole-dipole-, and hydrophobic interactions are taken explicitly into account. An interesting feature displayed by this potential is the presence of metastable intermediates between the unfolded and native states. We consider different types of confining potentials to describe proteins folding inside cages with repulsive or attractive walls. Using the Wang-Landau algorithm, we determine the density of states and analyze in detail the thermodynamical properties of the confined proteins for different sizes of the cages. We show that confinement dramatically reduces the phase space available to the protein and that the presence of intermediate states can be controlled by varying the properties of the confining potential. Cages with strongly attractive walls destabilize the intermediate states and lead to a two-state folding into a configuration that is less stable than the native structure. However, cages with slightly attractive walls enhance the stability of native structure and induce a folding process, which occurs through intermediate configurations.     

Dynamic torquemeter calibration of bicycle ergometers

Bicycle ergometers as widely used in both clinical testing and exercise physiology studies are mechanical, hydraulic, or electromechanical devices. They are thus subject to change and error, creating a need for repeated calibration. We have developed a compact inexpensive torquemeter that permits dynamic calibration of the entire range of an ergometer. The torquemeter continuously measures the input torque at the pedal shaft of the ergometer and thus includes all work done in the drivetrain. It also permits adjustment of electrically braked ergometers to a specified torque using internal adjustments to give correct scale readings. The torquemeter depends on a high carbon steel torsion spring whose ends are rotated in angular deflection by increasing applied torque. Relative rotation is sensed through a multiturn potentiometer, the resistance of which is measured externally through a slip ring contact.     

AUDRI, an instrument for the automated performance of kinetic and toxicity experiments with cultured cells.

A device for automatic manipulation of culture dishes has been developed to facilitate the execution of long-term cell culture experiments involving repetitive measurement of either cell killing or labeled precursor incorporation, or both. Solutions are added and withdrawn from 35 or 60 mm plastic culture dishes maintained under growth conditions, according to a preprogrammed schedule that can continue for an essentially indefinite period. Both fixed- and variable-volume addition of up to four different solutions can be specified, the former to a maximum of 5 ml and the latter to 444 μl in 3.5-μl increments. Provision is made for up to 48 pairs of cultures, the dishes of each pair receiving identical treatment. As many as 13 different treatments can be specified for a given experiment; these can be scheduled as closely as 1 min apart. The device is controlled by a minicomputer which is programmed with the experimental protocol by means of a punched paper tape prepared on a large computer. Some examples of its application are presented.     

Maintenance of mice in automatic rearing system. I. Rearing tests with ICR mice (author's transl)

Female ICR:JCL mice were reared in wire-mesh cages with nozzles for automatic water supply on a battery with an automatic washing system, and the evaluation of this system was made in comparison with the conventional feeding system with water bottles, alumite cages and changes of the bedding. In weight gains, feed intakes, water consumption, leucocyte and erythrocyte counts, hematocrit values or vaious organ weights during the period from 3 to 14 weeks of age, animals maintained by the automatic rearing system showed no significant difference as compared with those maintained by the conventional system, providing evidence for a conspicuous labor saving with the automatic control system.     

A machine vision system to detect and count laying hens in battery cages

Manually counting hens in battery cages on large commercial poultry farms is a challenging task: time-consuming and often inaccurate. Therefore, the aim of this study was to develop a machine vision system that automatically counts the number of hens in battery cages. Automatically counting hens can help a regulatory agency or inspecting officer to estimate the number of living birds in a cage and, thus animal density, to ensure that they conform to government regulations or quality certification requirements. The test hen house was 87 m long, containing 37 battery cages stacked in 6-story high rows on both sides of the structure. Each cage housed 18 to 30 hens, for a total of approximately 11 000 laying hens. A feeder moves along the cages. A camera was installed on an arm connected to the feeder, which was specifically developed for this purpose. A wide-angle lens was used in order to frame an entire cage in the field of view. Detection and tracking algorithms were designed to detect hens in cages; the recorded videos were first processed using a convolutional neural network (CNN) object detection algorithm called Faster R-CNN, with an input of multi-angular view shifted images. After the initial detection, the hens’ relative location along the feeder was tracked and saved using a tracking algorithm. Information was added with every additional frame, as the camera arm moved along the cages. The algorithm count was compared with that made by a human observer (the ‘gold standard’). A validation dataset of about 2000 images achieved 89.6% accuracy at cage level, with a mean absolute error of 2.5 hens per cage. These results indicate that the model developed in this study is practicable for obtaining fairly good estimates of the number of laying hens in battery cages.     

Responses of tsetse to ox sebum: a video study in the field

The behaviour of tsetse (mainly Glossina pallidipes Austen) around odour-baited targets, with or without a coating of ox sebum, was recorded in the field using video. The addition of sebum increased the total time a fly was in contact with the target, as well as the time spent flying around and landing on it. When carbon dioxide was released as part of the attractant odour plume, the presence of sebum on the target increased the number of landings made by each fly, but did not significantly affect the duration of each contact. When carbon dioxide was absent from the odour plume, sebum did not affect the number of landings made by flies but the duration of each contact with the target did increase. Evidence for an interactive effect of sebum and carbon dioxide was obtained. In addition, the presence of sebum on the target increased the percentage of landed flies which walked on its surface; such behaviour may represent an 'inspection' of the artificial host. The potential tsetse control application of the current findings are discussed.     

Methods of measuring the prevalence of pathogenic fungi on potato tubers

Methods are described whereby the prevalence of pathogenic fungi on seed potato tubers can be measured quickly and quantitatively. Eye-bearing plugs of tuber tissue, 8 mm diameter by 10 mm long, are excised, incubated over water at 15 °C for 5 days and then examined microscopically. The occurrence of fungi and macroscopic tuber symptoms are recorded directly on punched tape and tabulated by computer.     

Sequentiality of Daily Life Physiology: An Automatized Segmentation Approach

Based on the hypotheses that (1) a physiological organization exists inside each activity of daily life and (2) the pattern of evolution of physiological variables is characteristic of each activity, pattern changes should be detected on daily life physiological recordings. The present study aims at investigating whether a simple segmentation method can be set up to detect pattern changes on physiological recordings carried out during daily life. Heart and breathing rates and skin temperature have been non-invasively recorded in volunteers following scenarios made of “daily life” steps (13 records). An observer, undergoing the scenario, wrote down annotations during the recording time. Two segmentation procedures have been compared to the annotations, a visual inspection of the signals and an automatic program based on a trends detection algorithm applied to one physiological signal (skin temperature). The annotations resulted in a total number of 213 segments defined on the 13 records, the best visual inspection detected less segments (120) than the automatic program (194). If evaluated in terms of the number of correspondences between the times marks given by annotations and those resulting from both physiologically based segmentations, the automatic program was better than the visual inspection. The mean time lags between annotation and program time marks remain <60 s (the precision of annotation times marks). We conclude that physiological variables time series recorded in common life conditions exhibit different successive patterns that can be detected by a simple trends detection algorithm. Theses sequences are coherent with the corresponding annotated activity.     

BirdOriTrack: a new video‐tracking program for orientation research with migratory birds

Experimental research on the orientation of migratory songbirds is traditionally conducted using orientation funnels or automatic registration cages that record the directional activity of individual birds on paper or a computer. Most traditionally used funnel and cage designs do not permit investigators to observe detailed behavior of the birds and, therefore, we have gained little insight into the actual behavior of birds while they are exhibiting migratory restlessness and making directional choices. Such behavior can only be studied by direct observation or by video filming. Here, we present BirdOriTrack, a video‐tracking program for extracting time‐resolved, positional data of birds (and potentially other animal species) to determine their orientation relative to the center of a circular cage/funnel. With relatively inexpensive cameras, recording equipment, and cages, orientation experiments can easily be conducted and analyzed using BirdOriTrack. The program is designed to be flexible, allowing analysis of orientation behavior of birds of any size in different cage designs and in both controlled laboratory settings and field‐based studies. To demonstrate the program's utility, we show the results of preliminary field experiments on several species of migratory birds captured at a migration monitoring station. BirdOriTrack is freely available at http://canmove.lu.se/birdoritrack .     

Robust Triboelectric Nanogenerator Achieved by Centrifugal Force Induced Automatic Working Mode Transition

Material abrasion in contact‐based freestanding mode‐triboelectric nanogenerators (FS‐TENGs) seriously deteriorates device mechanical durability and electrical stability, which causes TENGs to be only applicable in the harvesting of mechanical energy at low‐frequency. Here, a wide‐frequency and ultra‐robust rotational TENG is reported that is composed of a built‐in traction rope structure and capable of transforming from contact mode to non‐contact mode automatically as driven by the centrifugal force. With optimizing the fixed x and y position on slider and center shaft, respectively, the mode transition threshold speed can be reduced to 225 rpm. Additionally, the automatic working mode transition TENG exhibits excellent electrical stability, which can maintain 90% electric output after over 24 h of continuous operation, while the contact and non‐contact mode TENGs only retain 30% and 2% output, respectively. The high stability and large output density ensure its usage in the fast and effective charging of commercial capacitors or electronics. This work provides a prospective strategy for rotational TENGs to extend the frequency operation region and mechanical durability for practical applications.     

The influence of environmental change on the behaviour of sheltered dogs

The majority of sheltered dogs are overlooked for purchase because they are considered undesirable by potential buyers. Many factors may determine a dog's appeal, although of interest here are the dog's behaviour and cage environment which can influence its desirability. People prefer dogs which are at the front rather than the back of the cage, quiet as opposed to barking, and alert rather than non-alert. Potential buyers also prefer dogs which are held in complex as opposed to barren environments. This study examined the behaviour of sheltered dogs in response to environmental change, to determine whether it influenced dog behaviour in ways that could be perceived as desirable to potential dog buyers, and/or had any effect upon the incidence of dogs purchased from the shelter. One hundred and twenty dogs sheltered by the Ulster Society for the Prevention of Cruelty to Animals were studied over a 4-h period. The dogs' position in the cage, vocalisation, and activity were investigated in response to increased human social stimulation, moving the dog's bed to the front of the cage, or suspending a toy from the front of the dog's cage. Social stimulation resulted in dogs spending more time at the front of the enclosure, more time standing, and slightly more time barking. Moving the bed to the front of the cage encouraged dogs to this position, but did not influence activity or vocalisation. Suspending a toy at the front of the pen exerted no effect on dog behaviour, although its presence in the pen may help to promote more positive perceptions of dog desirability. The incidence of dogs purchased from the rescue shelter increased whenever the dogs' cages were fitted with a bed at the front of the pen, whenever the dogs were subjected to increased regular human contact, and whenever a toy was placed at the front of the enclosure. Findings highlight the important role that cage environment can play in shaping the behaviour of sheltered dogs and influencing whether or not an animal will become purchased.     

Receptor potentials and action potentials in Drosera tentacles

Summary Voltage fluctuations identified as receptor potentials can be detected with electrodes applied to the mucilage surrounding the head of a tentacle of Drosera intermedia if the head is stimulated by contact with a live insect, by the touch of a clean, inert object, or by application of salt solutions. Associated with a low receptor potential are action potentials, which occur at a frequency dependent on the magnitude of the receptor potential. These action potentials can be detected with electrodes applied to any region of the stalk of the tentacle. Inflection of the lower stalk follows the occurrence of action potentials. Inflection is minute for isolated action potentials but large and rapid when several occur within a brief interval.The apparent amplitude of action potentials recorded from the stalk is independent of receptor potential amplitude, but that of action potentials recorded from the mucilage commonly decreases as the receptor potential deviates from the baseline and increases as it returns. It is suggested that variation of apparent amplitude of the action potentials may result from postulated variation in the resistance of receptor membranes.     

Small heat shock protein as a multifunctional scaffold: integrated tumor targeting and caspase imaging within a single cage

Protein cages have the potential to serve as biomaterials for the targeted therapeutic and imaging systems. As an effort to exploit small heat shock protein (Hsp) cages as multifunctional biomaterials, we demonstrate that chemically and genetically modified Hsp cages permeate the cells via cancer cell binding and subsequent endocytic internalization and can image caspase activity in the live cells. Moreover, we report here that these functional Hsp cages can be specifically accumulated to tumor tissues of tumor-bearing mice when administered intravenously through the lateral tail vein. These tumor-targeting properties could be explained by the prolonged in vivo circulation and enhanced permeability and retention (EPR) effect as well as the ligand-mediated binding to cancer cells. Furthermore, when combined with the caspase sensing ability, our Hsp cage allows us to monitor the therapeutic evaluation after anticancer drug treatment by imaging the caspase activity within tumors. Therefore, we demonstrate that the Hsp cages have multifunctional scaffolds amenable to genetic and chemical modifications without loss of the cagelike architecture and can be exploited as biomedical materials including drug or imaging agent carriers.     

Response characteristics of neurons in chick forebrain slices

Coronal sections were taken from the forebrains of domestic chicks, aged 1-20 days, and maintained in vitro. Extracellular recordings of neural activity were made from the intermediate part of the medial hyperstriatum ventrale (IMHV). Spontaneous activity was rarely recorded, but neuronal responses could be evoked by stimulation of various sites. Each recording point was surrounded by an arc of sites which, when stimulated, typically elicited a short-latency field potential. These 'local responses' could be recorded in slices from chicks of any age. Stimulation of more distant sites failed to evoke field potentials from the IMHV. Instead, trains of large, unit action potentials appeared on an undisturbed baseline. Such 'unit' responses could only be evoked by stimuli delivered at specific frequencies. They required facilitation, were of variable latency, and often finally decayed. The number of sites capable of evoking a 'unit' response from the IMHV fell dramatically in slices taken from chicks older than 4 days.     

An analysis of the nesting behaviour of Geotrupes spiniger Marsham (Coleoptera, Scarabaeidae)

Abstract. 1. Female G.spiniger adults working alone made nests each consisting of a vertical shaft leading to a series of horizontal brood chambers filled with dung brood masses. Oviposition near the tip of the brood mass occurred while the egg cell was being completed over the expanded ovipositor. The shaft above each brood mass was filled with soil excavated from the next brood chamber. A similar response also filled artificial diverticula. An avoidance reaction towards buried dung prevented damage to pre-existing brood masses. 2. Virgin females did not make nests and did not avoid buried dung, but after mating (at about 4 weeks after eclosion) both types of behaviour were released within a few hours. 3. The presence of dung was required to initiate but not to maintain nesting behaviour. If dung was removed after oviposition the chamber was filled with soil produced by renewed excavation. Cellulose pulp could substitute for dung in brood mass formation. 4. Beetles interchanged between burrows at different stages before oviposition readily repeated all pre-oviposition behaviour. They appeared to respond to the length of the shaft and of the brood chamber since they extended short shafts and short brood chambers considerably more than those of normal length. After oviposition the beetles continued to make brood masses even under abnormal conditions. 5. Tilting the cage through 90° caused beetles before oviposition to re-orientate their burrowing direction, but tilting just after oviposition caused them to make vertical brood masses. Placing the shaft in a horizontal position towards the end of brood mass formation postponed the termination of this phase. 6. Beetles repeatedly excavated shafts and chambers when transferred to new cages. Conversely they repeatedly made brood masses when maintained in preformed plaster-of-Paris burrows. 7. This nesting behaviour can be described as a reaction chain in which each action generates its own terminating stimulus and initiates the subsequent response. The behaviour before oviposition could be omitted or repeated as required by the environment, but after oviposition there was little response to external interference. These characteristics have direct relevance to the survival of the larvae.     

Thermoelectrically Cooled Temperature-Gradient Apparatus for Comparative Cell and Virus Temperature Studies

Establishment of a near-linear temperature gradient in an incubator has been accomplished by the application of heat to one terminus of a conducting body, normally a metal bar, and the removal of heat from the other terminus of the conducting body. Such incubators have been complex and unwieldy because of the need for mechanical refrigeration. We have described a simplified temperature gradient incubator which uses thermoelectric module cooling coupled with electric heating. Along the gradient, 20 stations in two parallel rows of 10, each accommodating a 30-ml plastic cell culture flask, were continually monitored by an electronic thermometer, and the temperatures were recorded. By manipulation of two simple potentiometer controls, any temperature gradient between 0 and 50 C could be obtained. Minor deviations which occurred between theoretically perfect and obtained temperature gradients were reproducible and readily measured. The gradient incubator was particularly applicable to (i) simultaneously studying a given biological activity over the entire temperature range supporting the growth of a given cell, virus, or microorganism, or (ii) precisely defining the upper or lower temperature limits of a biological system by 10-point determinations. Preliminary experiments have demonstrated the usefulness of the apparatus in characterizing the temperature limits for growth in vitro of cells of reptilian cell lines. The gradient incubator was also successfully utilized for the characterization of the effect of temperature on the efficiency of plating of amphibian viruses and possible temperature variants of those viruses.