1,879 research outputs found
Standardisation of Environmental Enrichment for Laboratory Mice and Rats: Utilisation, Practicality and Variation in Experimental Results
Rats and mice are the most commonly used species as laboratory animal models of diseases in biomedical research. Environmental factors such as cage size, number of cage mates and cage structure such as environmental enrichment can affect the physiology and behavioural development of laboratory animals and their well-being throughout their lives. Therefore compromising the animalsâ well-being due to inadequate environmental conditions would diminish the value of the research models. In order to improve laboratory animalsâ well-being and promote the quality of animal based biomedical research, it is fundamentally important that the environment of the animals meets the animalsâ species typical behavioural needs. Standardisation of environmental enrichment for laboratory rats and mice therefore should provide possibilities for the animals to engage in at least the essential behavioural needs such as social contact, nest building, exploring and foraging. There is a wide variety of environmental enrichment items commercially available for laboratory mice and rats. However, how these items are used by the animals, their practicality in the laboratory and whether these enrichments might lead to increased variation in experimental results have not been widely assessed. In this study, we implemented two standardised enrichment items (shelters, nesting materials) for rats and mice at different animal units. We instructed the animal care staff in monitoring the use of enrichment items by the animals by means of a daily score sheet system. The animal staff âs viewpoint on practicality of the standardised enrichment program was assessed with a monthly score sheet survey. Also we assessed whether the enriched environment affected breeding results and contributed to an increase in variation of experimental data from several participating current studies. Our results show that the animals readily used the provided enrichment items. A slight increase in workload for the animal staff was reported. However, the overall judgement was mainly reported as good. Breeding results and variation in experimental data did not reveal differences as compared to data from previous housing and/or non enriched housing conditions. Overall, the results indicate that standard environmental enrichment that is species appropriate may enhance the animalâs well-being without undesirable side effects on the experimental outcome and daily working routine of the animal care staff.
Long-term effects of husbandry procedures on stress-related parameters in male mice of two strains
In socially unstable groups of male laboratory mice, individuals may experience a chronic stress situation. Previous experiments have shown that the transfer of specific olfactory cues during cage cleaning, and the provision of nesting material decrease aggression and stress in group-housed male mice. In this study, the combined effect of these husbandry procedures were tested for their long-term effect on stress in groups of moderately aggressive (BALB/c) and severely aggressive (CD-1) male mice. The physiological and behavioural stress-related parameters used were body weight, food and water intake, spleen and thymus weight, adrenal tyrosine hydroxylase activity, urine corticosterone levels and behaviour in a cage emergence test. Long-term provision of nesting material and its transfer during cage cleaning was found to influence several stress-related physiological parameters. Mice housed in cages enriched with nesting material had lower urine corticosterone levels and heavier thymuses, and they consumed less food and water than standard-housed mice. Furthermore, marked differences were found between strains. CD-1 mice were less anxious in the cage emergence test, weighed more, ate and drank more, and had heavier thymuses but lighter spleens and lower corticosterone levels than BALB/c mice. We conclude that the long-term provision of nesting material, including the transfer of nesting material during cage cleaning, reduces stress and thereby enhances the welfare of laboratory mice.</p
Tree genetic resources at risk in South America: A spatial threat assessment to prioritize populations for conservation
Background
Humans threat the populations of tree species by overexploitation, deforestation, land use change, and climate change. We present a novel threat assessment at intraspecific level to support the conservation of genetic resources of 80 socioeconomically viable tree species in South America. In this assessment, we evaluate the threat status of Ecogeographic Range Segments (ERSs). ERSs are groups of populations of a specific species in a certain ecological zone of a particular grid cell of a speciesâ geographic occupancy.
Methods
We used species location records to determine the species distributions and speciesâspecific ERSs. We distinguished eight threat situations to assess the risk of extirpation of the ERSs of all 80 species. These threat situations were determined by large or little tree cover, low or high human pressure, and low or high climate change impact. Available layers of tree cover and threats were used to determine the levels of fragmentation and direct human pressure. Maxent niche modelling with two Global Circulation Models helped determining climate change impact by the 2050s.
Results
When all 80 species are considered, in total, 59% of the ERSs are threatened by little tree cover or high human pressure. When climate change is also considered, then 71â73% of the ERSs are threatened. When an increased risk of extirpation of populations outside protected areas is considered, then 84â86% of the ERSs are threatened. Seven species warrant special attention because all their ERSs are threatened across their whole distribution in South America: Balfourondendron riedelianum, Cariniana legalis, Dalbergia nigra, Handroanthus pulcherrimus, Pachira quintana, Prosopis flexuosa, and Prosopis pallida.
Conclusions
Our results confirm the urgency to set up a regional action plan for the conservation of tree genetic resources in South America. With this threat assessment, we aim to support governments and organizations who are taking up this task
Dynamics of OH(2Pi)-He collisions in combined electric and magnetic fields
We use accurate quantum mechanical calculations to analyze the effects of
parallel electric and magnetic fields on collision dynamics of OH(2Pi)
molecules. It is demonstrated that spin relaxation in 3He-OH collisions at
temperatures below 0.01 K can be effectively suppressed by moderate electric
fields of order 10 kV/cm. We show that electric fields can be used to
manipulate Feshbach resonances in collisions of cold molecules. Our results can
be verified in experiments with OH molecules in Stark decelerated molecular
beams and electromagnetic traps.Comment: 20 pages, 5 figures, submitted to Faraday Discuss. 142: Cold and
Ultracold Molecule
A20/TNFAIP3 heterozygosity predisposes to behavioral symptoms in a mouse model for neuropsychiatric lupus
Background: Neuropsychiatric lupus (NPSLE) refers to the neurological and psychiatric manifestations that are commonly observed in patients with systemic lupus erythematosus (SLE). An important question regarding the pathogenesis of NPSLE is whether the symptoms are caused primarily by CNS-intrinsic mechanisms or develop as a consequence of systemic autoimmunity. Currently used spontaneous mouse models for SLE have already contributed significantly to unraveling how systemic immunity affects the CNS. However, they are less suited when interested in CNS primary mechanisms. In addition, none of these models are based on genes that are associated with SLE. In this study, we evaluate the influence of A20, a well-known susceptibility locus for SLE, on behavior and CNS-associated changes in inflammatory markers. Furthermore, given the importance of environmental triggers for disease onset and progression, the influence of an acute immunological challenge was evaluated. Methods: Female and male A20 heterozygous mice (A20+/â) and wildtype littermates were tested in an extensive behavioral battery. This was done at the age of 10±2weeks and 24 â± â2 weeks to evaluate the impact of aging. To investigate the contribution of an acute immunological challenge, LPS was injected intracerebroventricularly at the age of 10±2weeks followed by behavioral analysis. Underlying molecular mechanisms were evaluated in gene expression assays on hippocampus and cortex. White blood cell count and blood-brain barrier permeability were analyzed to determine whether peripheral inflammation is a relevant factor. Results: A20 heterozygosity predisposes to cognitive symptoms that were observed at the age of 10 â± â2 weeks and 24 â± â2 weeks. Young A20+/â males and females showed a subtle cognitive phenotype (10±2weeks) with distinct neuroinflammatory phenotypes. Aging was associated with clear neuroinflammation in female A20+/â mice only. The genetic predisposition in combination with an environmental stimulus exacerbates the behavioral impairments related to anxiety, cognitive dysfunction and sensorimotor gating. This was predominantly observed in females. Furthermore, signs of neuroinflammation were solely observed in female A20+/â mice. All above observations were made in the absence of peripheral inflammation and of changes in blood-brain barrier permeability, thus consistent with the CNS-primary hypothesis. Conclusions: We show that A20 heterozygosity is a predisposing factor for NPSLE. Further mechanistic insight and possible therapeutic interventions can be studied in this mouse model that recapitulates several key hallmarks of the disease
APF-stal klaar voor onderzoek
Na ruim een jaar proefdraaien en meerdere technische aanpassingen functioneert de Air Pathogen Free-stal (APF-stal) technisch goed. De ventilatie en verwarming zijn goed te regelen en de in het hygiëneprotocol opgenomen maatregelen zijn goed uitvoerbaar
Selected nondigestible carbohydrates and prebiotics support the growth of probiotic fish bacteria mono-cultures in vitro
To search for nondigestible but fermentable (NDF) carbohydrates and prebiotics with a potency to promote the growth of selected bacteria in vitro.
The growth of three reference bacteria strains Bacillus subtilis LMG 7135(T), Carnobacterium piscicola LMG 9839, Lactobacillus plantarum LMG 9211 and one candidate probiotic bacteria Lactobacillus delbrueckii subsp. lactis was investigated over a minimum period of 48 h in the presence of beta-glucan, xylo-oligosaccharide, arabinoxylo-oligosaccharide, inulin, oligofructose and glucose. Besides the capability to grow on inulin and oligofructose containing media, a distinct high growth in beta-glucan based substrates and a low growth in (arabino)xylooligosaccharide containing media were evident for most bacteria tested. With the exception of B. subtilis and L. plantarum, other bacteria grew equally well or even better on different substrates than on glucose. The fermentation of studied carbohydrates by these micro-organisms was dominated by the production of acetic acid as the main short chain fatty acid.
Selected bacteria are able to ferment and grow on NDF and prebiotic carbohydrates but in a substrate dependent manner.
This study delivers a first screening of which NDF or prebiotic carbohydrates are the most promising for aquaculture feed supplementations
Four-channel System for Characterization of Josephson Parametric Amplifiers
The axion search experiments based on haloscopes at the Center for Axion and
Precision Physics Research (CAPP) of the Institute for Basic Science (IBS) in
South Korea are performed in the frequency range from 1 GHz to 6 GHz. In order
to perform the experiments in a strong magnetic field of 12 T and a
large-volume cavity of close to 40 liters, we use He wet dilution refrigerators
with immersed superconducting magnets. The measurements require continuous
operation for months without interruptions for microwave component
replacements. This is achieved by using different cryogenic engineering
approaches including microwave RF-switching. The critical components, defining
the scanning rate and the sensitivity of the setup, are the Josephson
parametric amplifiers (JPA) and cryogenic low noise amplifiers (cLNA) based on
high-electron-mobility-transistor (HEMT) technology. It is desirable for both
devices to have a wide frequency range and low noise close to the quantum limit
for the JPA. In this paper, we show a recent design of a 4-channel measurement
setup for JPA and HEMT measurements. The setup is based on a 4-channel wideband
noise source (NS) and is used for both JPA and HEMT gain and noise
measurements. The setup is placed at 20 mK inside the dry dilution
refrigerator. The NS is thermally decoupled from the environment using plastic
spacers, superconducting wires and superconducting coaxial cables. We show the
gain and noise temperature curves measured for 4 HEMT amplifiers and 2 JPAs in
one cool-downComment: to be published in JPS Conference Proceedings (LT29
CAPP Axion Search Experiments with Quantum Noise Limited Amplifiers
The axion is expected to solve the strong CP problem of quantum
chromodynamics and is one of the leading candidates for dark matter. CAPP in
South Korea has several axion search experiments based on cavity haloscopes in
the frequency range of 1-6 GHz. The main effort focuses on operation of the
experiments with the highest possible sensitivity. It requires maintenance of
the haloscopes at the lowest physical temperature in the range of mK and usage
of low noise components to amplify the weak axion signal. We report development
and operation of low noise amplifiers for 5 haloscope experiments targeting at
different frequency ranges. The amplifiers show noise temperatures approaching
the quantum limit.Comment: 6 pages, 7 figures, 29th International Conference on Low Temperature
Physics, August 18-24, 2022, Sapporo, Japa
Josephson Parametric Amplifier in Axion Experiments
The axion is a hypothetical particle, a promising candidate for dark matter,
and a solution to the strong CP problem. Axion haloscope search experiments
deal with a signal power comparable to noise uncertainty at millikelvin
temperature. We use a flux-driven Josephson parametric amplifier (JPA) with the
aim of approaching a noise level near the theoretically allowed limit of half
quanta. In our measurements to characterize the JPA we have found the added
noise to the system with a JPA as the first-stage amplifier to be lower than
110 mK at the frequencies from 0.938 GHz to 0.963 GHz.Comment: to be published in JPS Conference Proceedings (LT29
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