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Biology subjects

Ulrich, S.

Publications and source records attributed to Ulrich, S..

3 recordsLinked to original sources

Who gets lost and why: A representative cross-sectional survey on sociodemographic and vestibular determinants of wayfinding strategies

When we think of our family and friends, we probably know someone who is good at finding their way and someone else that easily get lost. We still know little about the biological and environmental factors that influence our navigational ability. Here, we investigated the frequency and sociodemographic determinants of wayfinding and their association with vestibular function in a representative cross-sectional sample (N = 783) of the adult German-speaking population. Wayfinding was assessed using the Wayfinding Strategy Scale, a self-report scale that produces two scores for each participant representing to what degree they rely on route-based or orientation (map-based) strategies. We were interested in the following research questions: (1) the frequency and determinants of wayfinding strategies in a population-based representative sample, (2) the relationship between vestibular function and strategy choice and (3) how sociodemographic factors influence general wayfinding ability as measured using a combined score from both strategy scores. Our linear regression models showed that being male, having a higher education, higher age and lower regional urbanization increased orientation strategy scores. Vertigo/dizziness reduced the scores of both the orientation and the route strategies. Using a novel approach, we grouped participants by their combined strategy scores in a multinomial regression model, to see whether individuals prefer one strategy over the other. The majority of individuals reported using either both or no strategy, instead of preferring one strategy over the other. Young age and reduced vestibular function were indicative of using no strategy. In summary, wayfinding ability depends on both biological and environmental factors; all sociodemographic factors except income. Over a third of the population, predominantly under the age of 35, does not successfully use either strategy. This represents a change in our wayfinding skills, which may result from the technological advances in navigational aids over the last few decades.

neuroscience

Identification of cereulide producing Bacillus cereus by MALDI-TOF MS

The Bacillus (B.) cereus group is genetically highly homogenous and consists of nine recognized species which are present worldwide. B. cereus sensu stricto play an important role in food-borne diseases by producing different toxins. Yet, only a small percentage of B. cereus strains are able to produce the heat stable depsipeptide cereulide, the causative agent of emetic food poisonings. To minimize the entry of emetic B. cereus into the food chain, food business operators are dependent on efficient and reliable methods enabling the differentiation between emetic and non-emetic strains. Currently, only time-consuming cell bioassays, molecular methods and tandem mass spectrometry are available for this purpose. Thus, the aim of the present study was to establish a fast and reliable method for the differentiation between emetic and non-emetic strains by MALDI-TOF MS. Selected isolates/strains of the B. cereus group (total n=110, i.e. emetic n=45, non-emetic n=65) were cultured on sheep blood agar for 48h.\n\nSubsequently, the cultures were directly analyzed by MALDI-TOF MS without prior extraction steps (direct smear method). The samples were measured in linear positive ionization mode in the mass range of m/z 800 - 1,800 Da. Using ClinProTools 3.0 statistical software and flex analyst, a differentiation between emetic and non-emetic isolates was possible with a rate of correct identification of 99.1 % by means of the evaluation of two specific biomarkers (m/z 1171 and 1187 Da).\n\nImportanceBacillus (B.) cereus plays an important role in food-borne diseases due to the production of different toxins, e.g. the heat stable depsipeptide cereulide. Only a small number of B. cereus strains are able to produce this toxin, the causative agent of emetic food poisonings. To minimize the entry of emetic B. cereus into the food chain, food business operators require efficient and reliable methods enabling the differentiation between emetic and non-emetic strains. The aim of the present study was to develop a fast and reliable method for the differentiation between emetic and non-emetic strains by MALDI-TOF MS. A differentiation between emetic and non-emetic isolates was possible with a rate of correct identification of 99.1 % by means of the evaluation of two specific biomarkers (m/z 1171 and 1187 Da).

microbiology

Ketogenic diet or BHB improves epileptiform spikes, memory, survival in Alzheimer’s model

Links between epilepsy and Alzheimers disease (AD) are seen in both human patients and mouse models. Human patients with AD may commonly have subclinical epileptiform spikes (EP spikes)1, and overt epilepsy is associated with more rapid cognitive decline2. Mechanistic studies in mouse models of Alzheimers disease (AD) have shown that altered network activity and epileptiform spikes stem from dysfunctional inhibitory interneurons3, which are key elements of cortical circuits underlying cognition4. Treatments that reduce epileptiform spikes improve cognition in these models5,6. Thus, targeting subclinical epileptiform activity may be a promising new therapeutic approach to AD7. Ketogenic diet (KD) has long been used to treat forms of epilepsy8, including Dravet syndrome, a childhood epilepsy caused by mutations in a gene that is critical for inhibitory interneuron function in mouse AD models5,9. However, the concurrent effects of a ketogenic diet on brain electrical activity, cognitive decline, and survival have not been tested, and the translational rationale and feasibility of such an intervention remain uncertain. Here we show that a ketogenic diet reduces epileptiform spikes in the hAPPJ20 mouse model of AD. Similar reduction of EP spikes is observed using a {beta}-hydroxybutyrate (BHB) ester in both AD and Dravet mice. A ketogenic diet improves context-dependent and visuo-spatial learning in hAPPJ20 mice. It also reduces the high seizure-related mortality observed in male mice of this model. Therapies derived from {beta}-hydroxybutyrate may have potential application in ameliorating cognitive dysfunction in AD through reducing subclinical epileptiform activity.

neuroscience