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1.
Proc Natl Acad Sci U S A ; 120(23): e2219310120, 2023 06 06.
Article in English | MEDLINE | ID: mdl-37253014

ABSTRACT

Speech, as the spoken form of language, is fundamental for human communication. The phenomenon of covert inner speech implies functional independence of speech content and motor production. However, it remains unclear how a flexible mapping between speech content and production is achieved on the neural level. To address this, we recorded magnetoencephalography in humans performing a rule-based vocalization task. On each trial, vocalization content (one of two vowels) and production form (overt or covert) were instructed independently. Using multivariate pattern analysis, we found robust neural information about vocalization content and production, mostly originating from speech areas of the left hemisphere. Production signals dynamically transformed upon presentation of the content cue, whereas content signals remained largely stable throughout the trial. In sum, our results show dissociable neural representations of vocalization content and production in the human brain and provide insights into the neural dynamics underlying human vocalization.


Subject(s)
Brain , Speech Perception , Humans , Speech , Magnetoencephalography/methods , Brain Mapping
2.
FASEB J ; 38(2): e23411, 2024 01 31.
Article in English | MEDLINE | ID: mdl-38243766

ABSTRACT

Autism spectrum disorder is discussed in the context of altered neural oscillations and imbalanced cortical excitation-inhibition of cortical origin. We studied here whether developmental changes in peripheral auditory processing, while preserving basic hearing function, lead to altered cortical oscillations. Local field potentials (LFPs) were recorded from auditory, visual, and prefrontal cortices and the hippocampus of BdnfPax2 KO mice. These mice develop an autism-like behavioral phenotype through deletion of BDNF in Pax2+ interneuron precursors, affecting lower brainstem functions, but not frontal brain regions directly. Evoked LFP responses to behaviorally relevant auditory stimuli were weaker in the auditory cortex of BdnfPax2 KOs, connected to maturation deficits of high-spontaneous rate auditory nerve fibers. This was correlated with enhanced spontaneous and induced LFP power, excitation-inhibition imbalance, and dendritic spine immaturity, mirroring autistic phenotypes. Thus, impairments in peripheral high-spontaneous rate fibers alter spike synchrony and subsequently cortical processing relevant for normal communication and behavior.


Subject(s)
Autism Spectrum Disorder , Autistic Disorder , Mice , Animals , Brain-Derived Neurotrophic Factor/genetics , Hearing , Phenotype
3.
Proc Biol Sci ; 290(2007): 20231503, 2023 Sep 27.
Article in English | MEDLINE | ID: mdl-37752844

ABSTRACT

Human language follows statistical regularities or linguistic laws. For instance, Zipf's law of brevity states that the more frequently a word is used, the shorter it tends to be. All human languages adhere to this word structure. However, it is unclear whether Zipf's law emerged de novo in humans or whether it also exists in the non-linguistic vocal systems of our primate ancestors. Using a vocal conditioning paradigm, we examined the capacity of marmoset monkeys to efficiently encode vocalizations. We observed that marmosets adopted vocal compression strategies at three levels: (i) increasing call rate, (ii) decreasing call duration and (iii) increasing the proportion of short calls. Our results demonstrate that marmosets, when able to freely choose what to vocalize, exhibit vocal statistical regularities consistent with Zipf's law of brevity that go beyond their context-specific natural vocal behaviour. This suggests that linguistic laws emerged in non-linguistic vocal systems in the primate lineage.

4.
PLoS Pathog ; 17(7): e1009682, 2021 07.
Article in English | MEDLINE | ID: mdl-34293063

ABSTRACT

Current mass drug administration (MDA) programs for the treatment of human river blindness (onchocerciasis) caused by the filarial worm Onchocerca volvulus rely on ivermectin, an anthelmintic originally developed for animal health. These treatments are primarily directed against migrating microfilariae and also suppress fecundity for several months, but fail to eliminate adult O. volvulus. Therefore, elimination programs need time frames of decades, well exceeding the life span of adult worms. The situation is worsened by decreased ivermectin efficacy after long-term therapy. To improve treatment options against onchocerciasis, a drug development candidate should ideally kill or irreversibly sterilize adult worms. Emodepside is a broad-spectrum anthelmintic used for the treatment of parasitic nematodes in cats and dogs (Profender and Procox). Our current knowledge of the pharmacology of emodepside is the result of more than 2 decades of intensive collaborative research between academia and the pharmaceutical industry. Emodepside has a novel mode of action with a broad spectrum of activity, including against extraintestinal nematode stages such as migrating larvae or macrofilariae. Therefore, emodepside is considered to be among the most promising candidates for evaluation as an adulticide treatment against onchocerciasis. Consequently, in 2014, Bayer and the Drugs for Neglected Diseases initiative (DNDi) started a collaboration to develop emodepside for the treatment of patients suffering from the disease. Macrofilaricidal activity has been demonstrated in various models, including Onchocerca ochengi in cattle, the parasite most closely related to O. volvulus. Emodepside has now successfully passed Phase I clinical trials, and a Phase II study is planned. This Bayer-DNDi partnership is an outstanding example of "One World Health," in which experience gained in veterinary science and drug development is translated to human health and leads to improved tools to combat neglected tropical diseases (NTDs) and shorten development pathways and timelines in an otherwise neglected area.


Subject(s)
Antiparasitic Agents/therapeutic use , Depsipeptides/therapeutic use , Drug Development/methods , Onchocerciasis/drug therapy , Humans
5.
PLoS Pathog ; 17(3): e1009297, 2021 03.
Article in English | MEDLINE | ID: mdl-33720993

ABSTRACT

Parasitic nematodes cause a massive worldwide burden on human health along with a loss of livestock and agriculture productivity. Anthelmintics have been widely successful in treating parasitic nematodes. However, resistance is increasing, and little is known about the molecular and genetic causes of resistance for most of these drugs. The free-living roundworm Caenorhabditis elegans provides a tractable model to identify genes that underlie resistance. Unlike parasitic nematodes, C. elegans is easy to maintain in the laboratory, has a complete and well annotated genome, and has many genetic tools. Using a combination of wild isolates and a panel of recombinant inbred lines constructed from crosses of two genetically and phenotypically divergent strains, we identified three genomic regions on chromosome V that underlie natural differences in response to the macrocyclic lactone (ML) abamectin. One locus was identified previously and encodes an alpha subunit of a glutamate-gated chloride channel (glc-1). Here, we validate and narrow two novel loci using near-isogenic lines. Additionally, we generate a list of prioritized candidate genes identified in C. elegans and in the parasite Haemonchus contortus by comparison of ML resistance loci. These genes could represent previously unidentified resistance genes shared across nematode species and should be evaluated in the future. Our work highlights the advantages of using C. elegans as a model to better understand ML resistance in parasitic nematodes.


Subject(s)
Chloride Channels/drug effects , Haemonchus/drug effects , Ivermectin/analogs & derivatives , Nematode Infections/drug therapy , Animals , Anthelmintics/pharmacology , Caenorhabditis elegans/drug effects , Caenorhabditis elegans/genetics , Drug Resistance/genetics , Ivermectin/pharmacology
6.
PLoS Pathog ; 17(6): e1009601, 2021 06.
Article in English | MEDLINE | ID: mdl-34077488

ABSTRACT

Onchocerciasis (river blindness), caused by the filarial worm Onchocerca volvulus, is a neglected tropical disease mostly affecting sub-Saharan Africa and is responsible for >1.3 million years lived with disability. Current control relies almost entirely on ivermectin, which suppresses symptoms caused by the first-stage larvae (microfilariae) but does not kill the long-lived adults. Here, we evaluated emodepside, a semi-synthetic cyclooctadepsipeptide registered for deworming applications in companion animals, for activity against adult filariae (i.e., as a macrofilaricide). We demonstrate the equivalence of emodepside activity on SLO-1 potassium channels in Onchocerca volvulus and Onchocerca ochengi, its sister species from cattle. Evaluation of emodepside in cattle as single or 7-day treatments at two doses (0.15 and 0.75 mg/kg) revealed rapid activity against microfilariae, prolonged suppression of female worm fecundity, and macrofilaricidal effects by 18 months post treatment. The drug was well tolerated, causing only transiently increased blood glucose. Female adult worms were mostly paralyzed; however, some retained metabolic activity even in the multiple high-dose group. These data support ongoing clinical development of emodepside to treat river blindness.


Subject(s)
Cattle Diseases/drug therapy , Depsipeptides/therapeutic use , Filaricides/therapeutic use , Large-Conductance Calcium-Activated Potassium Channels/drug effects , Onchocerciasis/drug therapy , Onchocerciasis/veterinary , Animals , Cattle , Onchocerca/drug effects
7.
PLoS Biol ; 17(8): e3000375, 2019 08.
Article in English | MEDLINE | ID: mdl-31454343

ABSTRACT

Songbirds are renowned for their acoustically elaborate songs. However, it is unclear whether songbirds can cognitively control their vocal output. Here, we show that crows, songbirds of the corvid family, can be trained to exert control over their vocalizations. In a detection task, three male carrion crows rapidly learned to emit vocalizations in response to a visual cue with no inherent meaning (go trials) and to withhold vocalizations in response to another cue (catch trials). Two of these crows were then trained on a go/nogo task, with the cue colors reversed, in addition to being rewarded for withholding vocalizations to yet another cue (nogo trials). Vocalizations in response to the detection of the go cue were temporally precise and highly reliable in all three crows. Crows also quickly learned to withhold vocal output in nogo trials, showing that vocalizations were not produced by an anticipation of a food reward in correct trials. The results demonstrate that corvids can volitionally control the release and onset of their vocalizations, suggesting that songbird vocalizations are under cognitive control and can be decoupled from affective states.


Subject(s)
Crows/physiology , Vocalization, Animal/physiology , Volition/physiology , Acoustics , Animals , Cognition/physiology , Learning/physiology , Male , Neurons/physiology , Songbirds/physiology
8.
Public Health ; 195: 61-69, 2021 Jun.
Article in English | MEDLINE | ID: mdl-34058627

ABSTRACT

OBJECTIVE: The objective of this study was to synthesise evidence from primary care-based interventions for the treatment of obesity in adults and the elderly. STUDY DESIGN: Systematic review. METHODS: Eight electronic databases (MEDLINE, Lilacs, Embase, Psycinfo, Cochrane, WHOLIS, Open Gray and Scholar Google) were searched. There was no limitation on publication period; articles published in English, Portuguese or Spanish were included. The selection, data extraction and quality analyses were performed by three reviewers. RESULTS: A literature search retrieved 6464 publications, of which 5120 publications were excluded after reading the title/abstract and 293 after reading the full text. In total, 56 publications, representing 72 interventions were included. All studies were published between 2000 and 2020. Most studies were conducted in high-income countries. The mean duration of interventions was 11.5 months (SD: 7.5), ranging from 3 to 44 months. Most interventions were effective for body mass index reduction, weight loss and waist circumference change. CONCLUSION: Our study showed that most interventions were effective for outcomes analysed in adults and the elderly. We also found some literature gaps, such as the need to implement and evaluate obesity after intervention and the requirement to carry out more studies in low- and middle-income countries.


Subject(s)
Obesity , Weight Loss , Adult , Aged , Body Mass Index , Humans , Obesity/epidemiology , Obesity/therapy , Primary Health Care , Waist Circumference
9.
Eur J Neurosci ; 52(6): 3531-3544, 2020 09.
Article in English | MEDLINE | ID: mdl-32170972

ABSTRACT

Any transmission of vocal signals faces the challenge of acoustic interferences such as heavy rain, wind, animal or urban sounds. Consequently, several mechanisms and strategies have evolved to optimize signal-to-noise ratio. Examples to increase detectability are the Lombard effect, an involuntary rise in call amplitude in response to masking ambient noise, which is often associated with other vocal changes such as call frequency and duration, as well as the animals' capability of limiting calling to periods where noise perturbation is absent. Previous studies revealed vocal flexibility and various audio-vocal integration mechanisms in marmoset monkeys. Using acoustic perturbation triggered by vocal behaviour, we investigated whether marmosets are capable of exhibiting changes in call structure when perturbing noise starts after call onset or whether such effects only occur if noise perturbation starts prior to call onset. We show that marmosets are capable of rapidly modulating call amplitude and frequency in response to such noise perturbation. Vocalizations swiftly increased call frequency after noise onset indicating a rapid effect of perturbing noise on vocal motor production. Call amplitudes were also affected. Interestingly, however, the marmosets did not exhibit the Lombard effect as previously reported but decreased call intensity in response to noise. Our findings indicate that marmosets possess a general avoidance strategy to call in the presence of ambient noise and suggest that these animals are capable of counteracting a previously thought involuntary audio-vocal mechanism, the Lombard effect. These findings will pave the way to investigate the underlying audio-vocal integration mechanisms explaining these behaviours.


Subject(s)
Callithrix , Vocalization, Animal , Acoustics , Animals , Noise , Sound
10.
PLoS Pathog ; 14(10): e1007226, 2018 10.
Article in English | MEDLINE | ID: mdl-30372484

ABSTRACT

Benzimidazoles (BZ) are essential components of the limited chemotherapeutic arsenal available to control the global burden of parasitic nematodes. The emerging threat of BZ resistance among multiple nematode species necessitates the development of novel strategies to identify genetic and molecular mechanisms underlying this resistance. All detection of parasitic helminth resistance to BZ is focused on the genotyping of three variant sites in the orthologs of the ß-tubulin gene found to confer resistance in the free-living nematode Caenorhabditis elegans. Because of the limitations of laboratory and field experiments in parasitic nematodes, it is difficult to look beyond these three sites to identify additional mechanisms that might contribute to BZ resistance in the field. Here, we took an unbiased genome-wide mapping approach in the free-living nematode species C. elegans to identify the genetic underpinnings of natural resistance to the commonly used BZ, albendazole (ABZ). We found a wide range of natural variation in ABZ resistance in natural C. elegans populations. In agreement with known mechanisms of BZ resistance in parasites, we found that a majority of the variation in ABZ resistance among wild C. elegans strains is caused by variation in the ß-tubulin gene ben-1. This result shows empirically that resistance to ABZ naturally exists and segregates within the C. elegans population, suggesting that selection in natural niches could enrich for resistant alleles. We identified 25 distinct ben-1 alleles that are segregating at low frequencies within the C. elegans population, including many novel molecular variants. Population genetic analyses indicate that ben-1 variation arose multiple times during the evolutionary history of C. elegans and provide evidence that these alleles likely occurred recently because of local selective pressures. Additionally, we find purifying selection at all five ß-tubulin genes, despite predicted loss-of-function variants in ben-1, indicating that BZ resistance in natural niches is a stronger selective pressure than loss of one ß-tubulin gene. Furthermore, we used genome-editing to show that the most common parasitic nematode ß-tubulin allele that confers BZ resistance, F200Y, confers resistance in C. elegans. Importantly, we identified a novel genomic region that is correlated with ABZ resistance in the C. elegans population but independent of ben-1 and the other ß-tubulin loci, suggesting that there are multiple mechanisms underlying BZ resistance. Taken together, our results establish a population-level resource of nematode natural diversity as an important model for the study of mechanisms that give rise to BZ resistance.


Subject(s)
Benzimidazoles/pharmacology , Caenorhabditis elegans/genetics , Drug Resistance/genetics , Genetic Loci , Helminth Proteins/genetics , Immunity, Innate/genetics , Tubulin/genetics , Animals , Anthelmintics/pharmacology , Caenorhabditis elegans/drug effects , Gene Frequency , Genetic Variation , Genetics, Population
11.
Am J Emerg Med ; 37(10): 1864-1870, 2019 10.
Article in English | MEDLINE | ID: mdl-30639128

ABSTRACT

OBJECTIVE: Emergency Department Observation Units (Obs Units) provide a setting and a mechanism for further care of Emergency Department (ED) patients. Our hospital has a protocol-driven, type 1, complex 20 bed Obs Unit with 36 different protocols. We wanted to understand how the different protocols performed and what types of care were provided. METHODS: This was an IRB-approved, retrospective chart review study. A random 10% of ED patient charts with a "transfer to observation" order were selected monthly from October 2015 through June 2017. This database was designed to identify high and low functioning protocols based on length of stays (LOS) and admission rates. RESULTS: Over 20 months, a total of 984 patients qualified for the study. The average age was 49.5 ±â€¯17.2 years, 57.3% were women, and 32.3% were non-Caucasian. The admission rate was 23.5% with an average LOS in observation of 13.7 h [95% CI 13.3-14.1]. Thirty day return rate was 16.8% with 5.3% of the patients returning to the ED within the first 72 h. Thirty six different protocols were used, with the most common being chest pain (13.9%) and general (13.2%). Almost 70% received a consultation from another service, and 7.2% required a procedure while in observation. Procedures included fluoroscopic-guided lumbar punctures, endoscopies, dental extractions, and catheter replacements (nephrostomy, gastrostomy, and biliary tubes). CONCLUSIONS: An Obs Unit can care for a wide variety of patients who require multiple consultations, procedures, and care coordination while maintaining an acceptable length of stay and admission rate.


Subject(s)
Clinical Observation Units/organization & administration , Emergency Service, Hospital/organization & administration , Adult , Aged , Aged, 80 and over , Clinical Observation Units/statistics & numerical data , Clinical Protocols , Emergency Service, Hospital/statistics & numerical data , Female , Humans , Length of Stay/statistics & numerical data , Male , Middle Aged , Outcome and Process Assessment, Health Care , Patient Admission/statistics & numerical data , Practice Patterns, Physicians'/statistics & numerical data , Quality Improvement/organization & administration , Quality Improvement/statistics & numerical data , Quality Indicators, Health Care/statistics & numerical data , Retrospective Studies
12.
Phys Chem Chem Phys ; 20(23): 16266-16275, 2018 Jun 13.
Article in English | MEDLINE | ID: mdl-29863201

ABSTRACT

The hydrogen absorption properties of metal closo-borate/metal hydride composites, M2B10H10-8MH and M2B12H12-10MH, M = Li or Na, are studied under high hydrogen pressures to understand the formation mechanism of metal borohydrides. The hydrogen storage properties of the composites have been investigated by in situ synchrotron radiation powder X-ray diffraction at p(H2) = 400 bar and by ex situ hydrogen absorption measurements at p(H2) = 526 to 998 bar. The in situ experiments reveal the formation of crystalline intermediates before metal borohydrides (MBH4) are formed. On the contrary, the M2B12H12-10MH (M = Li and Na) systems show no formation of the metal borohydride at T = 400 °C and p(H2) = 537 to 970 bar. 11B MAS NMR of the M2B10H10-8MH composites reveal that the molar ratio of LiBH4 or NaBH4 and the remaining B species is 1 : 0.63 and 1 : 0.21, respectively. Solution and solid-state 11B NMR spectra reveal new intermediates with a B : H ratio close to 1 : 1. Our results indicate that the M2B10H10 (M = Li, Na) salts display a higher reactivity towards hydrogen in the presence of metal hydrides compared to the corresponding [B12H12]2- composites, which represents an important step towards understanding the factors that determine the stability and reversibility of high hydrogen capacity metal borohydrides for hydrogen storage.

13.
Theor Appl Genet ; 130(9): 1801-1817, 2017 Sep.
Article in English | MEDLINE | ID: mdl-28567664

ABSTRACT

KEY MESSAGE: Genetic diversity in elite rye germplasm as well as F 2:3 testcross design enables fast QTL mapping to approach genes controlling grain yield, grain weight, tiller number and heading date in rye hybrids. Winter rye (Secale cereale L.) is a multipurpose cereal crop closely related to wheat, which offers the opportunity for a sustainable production of food and feed and which continues to emerge as a renewable energy source for the production of bioethanol and biomethane. Rye contributes to increase agricultural crop species diversity particularly in Central and Eastern Europe. In contrast to other small grain cereals, knowledge on the genetic architecture of complex inherited, agronomic important traits is yet limited for the outbreeding rye. We have performed a QTL analysis based on a F2:3 design and testcross performance of 258 experimental hybrids in multi-environmental field trials. A genetic linkage map covering 964.9 cM based on SSR, conserved-orthologous set (COS), and mixed-phase dominant DArT markers allowed to describe 22 QTL with significant effects for grain yield, heading date, tiller number, and thousand grain weight across seven environments. Using rye COS markers, orthologous segments for these traits have been identified in the rice genome, which carry cloned and functionally characterized rice genes. The initial genome scan described here together with the existing knowledge on candidate genes provides the basis for subsequent analyses of the genetic and molecular mechanisms underlying agronomic important traits in rye.


Subject(s)
Genome, Plant , Quantitative Trait Loci , Secale/genetics , Chromosome Mapping , Crops, Agricultural/genetics , Crops, Agricultural/growth & development , Genetic Linkage , Phenotype , Secale/growth & development
14.
J Neurosci ; 35(18): 7030-40, 2015 May 06.
Article in English | MEDLINE | ID: mdl-25948255

ABSTRACT

Complex audio-vocal integration systems depend on a strong interconnection between the auditory and the vocal motor system. To gain cognitive control over audio-vocal interaction during vocal motor control, the PFC needs to be involved. Neurons in the ventrolateral PFC (VLPFC) have been shown to separately encode the sensory perceptions and motor production of vocalizations. It is unknown, however, whether single neurons in the PFC reflect audio-vocal interactions. We therefore recorded single-unit activity in the VLPFC of rhesus monkeys (Macaca mulatta) while they produced vocalizations on command or passively listened to monkey calls. We found that 12% of randomly selected neurons in VLPFC modulated their discharge rate in response to acoustic stimulation with species-specific calls. Almost three-fourths of these auditory neurons showed an additional modulation of their discharge rates either before and/or during the monkeys' motor production of vocalization. Based on these audio-vocal interactions, the VLPFC might be well positioned to combine higher order auditory processing with cognitive control of the vocal motor output. Such audio-vocal integration processes in the VLPFC might constitute a precursor for the evolution of complex learned audio-vocal integration systems, ultimately giving rise to human speech.


Subject(s)
Acoustic Stimulation/methods , Auditory Pathways/physiology , Auditory Perception/physiology , Prefrontal Cortex/physiology , Vocalization, Animal/physiology , Animals , Brain Mapping/methods , Haplorhini , Macaca mulatta , Male , Photic Stimulation/methods , Psychomotor Performance/physiology
15.
J Exp Biol ; 219(Pt 11): 1744-9, 2016 06 01.
Article in English | MEDLINE | ID: mdl-27252457

ABSTRACT

The evolutionary origins of human language are obscured by the scarcity of essential linguistic characteristics in non-human primate communication systems. Volitional control of vocal utterances is one such indispensable feature of language. We investigated the ability of two monkeys to volitionally utter species-specific calls over many years. Both monkeys reliably vocalized on command during juvenile periods, but discontinued this controlled vocal behavior in adulthood. This emerging disability was confined to volitional vocal production, as the monkeys continued to vocalize spontaneously. In addition, they continued to use hand movements as instructed responses during adulthood. This greater vocal flexibility of monkeys early in ontogeny supports the neoteny hypothesis in human evolution. This suggests that linguistic capabilities were enabled via an expansion of the juvenile period during the development of humans.


Subject(s)
Aging/physiology , Cognition/physiology , Vocalization, Animal/physiology , Animals , Macaca mulatta , Male , Reaction Time/physiology , Time Factors
16.
Proc Natl Acad Sci U S A ; 110(10): 4063-8, 2013 Mar 05.
Article in English | MEDLINE | ID: mdl-23431172

ABSTRACT

The Lombard effect, an involuntary rise in call amplitude in response to masking ambient noise, represents one of the most efficient mechanisms to optimize signal-to-noise ratio. The Lombard effect occurs in birds and mammals, including humans, and is often associated with several other vocal changes, such as call frequency and duration. Most studies, however, have focused on noise-dependent changes in call amplitude. It is therefore still largely unknown how the adaptive changes in call amplitude relate to associated vocal changes such as frequency shifts, how the underlying mechanisms are linked, and if auditory feedback from the changing vocal output is needed. Here, we examined the Lombard effect and the associated changes in call frequency in a highly vocal mammal, echolocating horseshoe bats. We analyzed how bandpass-filtered noise (BFN; bandwidth 20 kHz) affected their echolocation behavior when BFN was centered on different frequencies within their hearing range. Call amplitudes increased only when BFN was centered on the dominant frequency component of the bats' calls. In contrast, call frequencies increased for all but one BFN center frequency tested. Both amplitude and frequency rises were extremely fast and occurred in the first call uttered after noise onset, suggesting that no auditory feedback was required. The different effects that varying the BFN center frequency had on amplitude and frequency rises indicate different neural circuits and/or mechanisms underlying these changes.


Subject(s)
Chiroptera/physiology , Echolocation/physiology , Acoustic Stimulation , Animals , Female , Hearing/physiology , Male , Noise , Perceptual Masking/physiology , Signal-To-Noise Ratio , Vocalization, Animal/physiology
17.
Proc Natl Acad Sci U S A ; 110(3): E250-9, 2013 Jan 15.
Article in English | MEDLINE | ID: mdl-23271804

ABSTRACT

How diversity evolves and persists in biofilms is essential for understanding much of microbial life, including the uncertain dynamics of chronic infections. We developed a biofilm model enabling long-term selection for daily adherence to and dispersal from a plastic bead in a test tube. Focusing on a pathogen of the cystic fibrosis lung, Burkholderia cenocepacia, we sequenced clones and metagenomes to unravel the mutations and evolutionary forces responsible for adaptation and diversification of a single biofilm community during 1,050 generations of selection. The mutational patterns revealed recurrent evolution of biofilm specialists from generalist types and multiple adaptive alleles at relatively few loci. Fitness assays also demonstrated strong interference competition among contending mutants that preserved genetic diversity. Metagenomes from five other independently evolved biofilm lineages revealed extraordinary mutational parallelism that outlined common routes of adaptation, a subset of which was found, surprisingly, in a planktonic population. These mutations in turn were surprisingly well represented among mutations that evolved in cystic fibrosis isolates of both Burkholderia and Pseudomonas. These convergent pathways included altered metabolism of cyclic diguanosine monophosphate, polysaccharide production, tricarboxylic acid cycle enzymes, global transcription, and iron scavenging. Evolution in chronic infections therefore may be driven by mutations in relatively few pathways also favored during laboratory selection, creating hope that experimental evolution may illuminate the ecology and selective dynamics of chronic infections and improve treatment strategies.


Subject(s)
Biofilms/growth & development , Burkholderia cenocepacia/genetics , Burkholderia cenocepacia/pathogenicity , Bacterial Adhesion , Base Sequence , Burkholderia Infections/etiology , Burkholderia Infections/microbiology , Burkholderia cenocepacia/isolation & purification , Burkholderia cenocepacia/physiology , Chronic Disease , Cyclic GMP/analogs & derivatives , Cyclic GMP/metabolism , Cystic Fibrosis/complications , Cystic Fibrosis/microbiology , DNA, Bacterial/genetics , Directed Molecular Evolution , Ecosystem , Genome, Bacterial , Humans , Lung Diseases/etiology , Lung Diseases/microbiology , Mannose/metabolism , Metagenome , Mutation , Opportunistic Infections/etiology , Opportunistic Infections/microbiology , Phylogeny , Selection, Genetic
18.
J Exp Biol ; 217(Pt 14): 2440-4, 2014 Jul 15.
Article in English | MEDLINE | ID: mdl-24855671

ABSTRACT

One of the most efficient mechanisms to optimize signal-to-noise ratios is the Lombard effect - an involuntary rise in call amplitude due to ambient noise. It is often accompanied by changes in the spectro-temporal composition of calls. We examined the effects of broadband-filtered noise on the spectro-temporal composition of horseshoe bat echolocation calls, which consist of a constant-frequency component and initial and terminal frequency-modulated components. We found that the frequency-modulated components became larger for almost all noise conditions, whereas the bandwidth of the constant-frequency component increased only when broadband-filtered noise was centered on or above the calls' dominant or fundamental frequency. This indicates that ambient noise independently modifies the associated acoustic parameters of the Lombard effect, such as spectro-temporal features, and could significantly affect the bat's ability to detect and locate targets. Our findings may be of significance in evaluating the impact of environmental noise on echolocation behavior in bats.


Subject(s)
Chiroptera/physiology , Echolocation/physiology , Perceptual Masking , Signal-To-Noise Ratio , Vocalization, Animal/physiology , Acoustic Stimulation , Animals , Noise
19.
Behav Brain Sci ; 37(6): 529-46, 2014 Dec.
Article in English | MEDLINE | ID: mdl-24827156

ABSTRACT

Any account of "what is special about the human brain" (Passingham 2008) must specify the neural basis of our unique ability to produce speech and delineate how these remarkable motor capabilities could have emerged in our hominin ancestors. Clinical data suggest that the basal ganglia provide a platform for the integration of primate-general mechanisms of acoustic communication with the faculty of articulate speech in humans. Furthermore, neurobiological and paleoanthropological data point at a two-stage model of the phylogenetic evolution of this crucial prerequisite of spoken language: (i) monosynaptic refinement of the projections of motor cortex to the brainstem nuclei that steer laryngeal muscles, presumably, as part of a "phylogenetic trend" associated with increasing brain size during hominin evolution; (ii) subsequent vocal-laryngeal elaboration of cortico-basal ganglia circuitries, driven by human-specific FOXP2 mutations.;>This concept implies vocal continuity of spoken language evolution at the motor level, elucidating the deep entrenchment of articulate speech into a "nonverbal matrix" (Ingold 1994), which is not accounted for by gestural-origin theories. Moreover, it provides a solution to the question for the adaptive value of the "first word" (Bickerton 2009) since even the earliest and most simple verbal utterances must have increased the versatility of vocal displays afforded by the preceding elaboration of monosynaptic corticobulbar tracts, giving rise to enhanced social cooperation and prestige. At the ontogenetic level, the proposed model assumes age-dependent interactions between the basal ganglia and their cortical targets, similar to vocal learning in some songbirds. In this view, the emergence of articulate speech builds on the "renaissance" of an ancient organizational principle and, hence, may represent an example of "evolutionary tinkering" (Jacob 1977).


Subject(s)
Animal Communication , Biological Evolution , Communication , Primates/physiology , Speech/physiology , Animals , Humans , Social Behavior
20.
Article in English | MEDLINE | ID: mdl-38805129

ABSTRACT

PURPOSE: In addition to molar incisor hypomineralisation, the occurrence of enamel hypomineralisation in the primary dentition has become increasingly important in recent years. Hypomineralised second primary molar (HSPM) is defined as hypomineralisation of systemic origin affecting from one to all four second primary molars. Some years ago, the "Würzburg concept" was introduced, which proposed a grading of MIH findings (MIH treatment need index) in combination with an appropriate treatment plan depending on the severity of the affected tooth. Recently, this concept was updated and new treatment approaches have been added. However, currently, the concept solely addresses the treatment plan for permanent teeth. As there is a need to expand its scope to encompass primary teeth and, consequently, HSPM, this paper seeks to develop the second component of the Würzburg concept, the treatment plan, for the primary dentition in response to the increased focus on the disease in recent years. Although the evidence base for the different treatment options is still weak, there is a need for guidance for clinicians in their day-to-day practice. METHODS: The authors conducted a comprehensive review of the literature, encompassing clinical and laboratory studies along with published guidelines. RESULTS: The treatment plan of the HSPM Würzburg concept contains prophylactic and regenerative aspects, non-invasive interventions, temporary and permanent restorative techniques, and extraction. CONCLUSIONS: The intention is to provide practical guidance to practitioners, acknowledging the necessity for further validation through clinical trials.

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