Journal: Matters

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Publisher

Sciencematters

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ISSN

2297-8240

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Filters

2016 - 20175
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Publications 1 - 5 of 5
  • Particle concentration influences inertial focusing in Multiorifice Flow Fractionation microfluidic devices
    Item type: Journal Article
    Casadevall i Solvas, Xavier; deMello, Andrew J. (2016)
    Matters
    Multiorifice - Flow - Fractionation (MOFF) devices have been used for the separation of microparticles and cells according to their size and the degree of inertia (i.e. Re number). Herein an additional parameter, particle concentration; is reported to affect the performance of MOFF when the remaining conditions are unchanged. Particularly, at low concentrations focusing occurs efficiently at the center of these devices, while at higher concentrations particles tend to accumulate near the channel walls. This indicates that particle-particle interactions are a key components in the performances of these devices.
  • S-Sulfhydration of the Catalytic Cysteine in the Rhodanese Domain of YgaP is Complex Dynamic Process
    Item type: Journal Article
    Eichmann, Cédric; Tzitzilonis, Christos; Kwiatkowski, Witek; et al. (2016)
    Matters
    The S-sulfhydration of cysteine residues in proteins has emerged as a common modifi cation that can modulate the activity of a protein. The ubiquity of the rhodanese domain and its occurrence in a wide variety of protein families indicates that it has diverse roles in physiology. Contrary to common expectations, previous structural studies of several rhodanese domains concluded that S-sulfhydration does not induce a structural change in the protein. The presented x-ray structure of a thiosulfate- treated crystal of the rho danese domain of the E. coli integral membrane protein YgaP reveals two important findings: (1) The S-sulfhydrated catalytic cysteine C63 adopts an atypical conformation. (2) S-sulfhydration leads to a destabilization of the N-terminal part of the helix adjacent to the catalytic loop. These findings assert that S-sulfhydration is accompanied by a specific and complex dynamic process.
  • Lesions of a higher auditory brain area during a sensorimotor period do not impair birdsong learning
    Item type: Journal Article
    Canopoli, Alessandro; Zai, Anja T.; Hahnloser, Richard H.R. (2016)
    Matters
    One important function of the nervous system is to form and retrieve memories to direct behavior. A prime example of memorization occurs in songbirds when they imitate the songs of another bird heard early in life. Although many brain areas required for song learning have been identified, their separate roles in memory formation and retrieval remain unclear. In juvenile male zebra finches, we test the role of a higher auditory cortical area in memory retrieval. The Caudal Medial Nidopallium (NCM) has previously been shown to be necessary for song memory acquisition and is thus a likely location for holding the memory of tutor song necessary for learning. We extensively exposed young birds to tutor song after which we performed large bilateral lesions in NCM using injection of ibotenic acid. We observed successful song copying in lesioned animals, comparable to song behavior in untreated control birds. Our results show that intact NCM is not required to guide vocal learning based on a previously formed song memory
  • Using Tandem Behaviour-PET to Examine Dopaminergic Signalling Underlying Exploration
    Item type: Journal Article
    Müller Herde, Adrienne; Ioanas, Horea-Ioan; Boss, Silvan D.; et al. (2017)
    Matters
    Here, we examine the potential of positron emission tomography (PET), a non-invasive technique that detects the location of a small molecule within a subject in real-time with resolution in the micrometre range, in providing insight into the role of dopaminergic signalling in exploratory behaviours. Using a pilot of five adult mice, we recorded the behaviour of each subject during a 15-min free exploration period and then performed PET imaging with the F-labelled high affinity dopamine D2/D3 receptor antagonist 18 F- fallypride. A correlation matrix of behaviours and brain regions of interest revealed some interesting correlations. In particular, we find a decreased standardised uptake value (SUV) for 18 F-fallypride in the hippocampal formation and amygdala in subjects that exhibited high levels of unassisted rearing. This finding suggests that either a higher concentration of dopamine in these areas, or lower D2/D3 receptor availability, is associated with increased exploratory behaviour. In contrast, we found that high SUVs for 18 F-fallypride throughout the brain correlated most strongly with immobility and body grooming, suggesting these behaviours dominate during times of low global dopamine/dopamine receptor binding. This pilot study serves as an example of the potential for using tandem behaviour-PET to identify novel brain-behaviour interactions, but additional refinements to the methods are warranted before full-scale studies are engaged.
  • Bilateral neurotoxic lesions in NCM before tutoring onset do not prevent successful tutor song learning
    Item type: Journal Article
    Canopoli, Alessandro; Zai, Anja T.; Hahnloser, Richard H.R. (2017)
    Matters
    Sensorimotor learning crucially depends on the ability to acquire a sensory memory for shaping motor commands. Such learning is conveniently studied in young songbirds when they memorize the song of an adult singer and gradually transform their own vocalizations toward the memorized target song. Here we study the involvement of the Caudal Medial Nidopallium (NCM), a higher auditory cortical area, in acquisition of a song memory. NCM has previously been shown to be involved in tutor song memorization. To study the necessity of NCM in this process, we perform large irreversible NCM lesions using ibotenic acid injections in about 40-days old juvenile zebra finches, before their first exposure to tutor song. Surprisingly, NCM-lesioned juveniles successfully copied the tutor song at least as well as untreated control animals, showing that a fully intact NCM is not required for tutor song memory formation and normal song development.
Publications 1 - 5 of 5