A gene cadre orchestrates the normal development of sensory and non-sensory cells in the inner ear, segregating the cochlea with a distinct tonotopic sound frequency map, similar brain projection, and five vestibular end-organs. However, the role of genes driving the ear development is largely unknown. Here, we show double deletion of the Iroquois homeobox 3 and 5 transcription factors (Irx3/5 DKO) leads to the fusion of the saccule and the cochlear base. The overlying otoconia and tectorial membranes are absent in the Irx3/5 DKO inner ear, and the primary auditory neurons project fibers to both the saccule and cochlear hair cells. The central neuronal projections from the cochlear apex-base contour are not fully segregated into a dorsal and ventral innervation in the Irx3/5 DKO cochlear nucleus, obliterating the characteristic tonotopic auditory map. Additionally, Irx3/5 deletion reveals a pronounced cochlear-apex-vestibular "vestibular-cochlear" nerve (VCN) bilateral connection that is less noticeable in wild-type control mice. Moreover, the incomplete segregation of apex and base projections that expands fibers to connect with vestibular nuclei. The results suggest the mammalian cochlear apex is a derived lagena reminiscent of sarcopterygians. Thus, Irx3 and 5 are potential evolutionary branch-point genes necessary for balance-sound segregation, which fused into a saccule-cochlea organization.

• MeSH
• homeodoménové proteiny * genetika   metabolismus   MeSH
• kochlea * fyziologie   MeSH
• myši knockoutované * MeSH
• myši MeSH
• sakulus a utrikulus * fyziologie   MeSH
• sluchová dráha fyziologie   MeSH
• transkripční faktory * genetika   metabolismus   nedostatek   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Bilateral asymmetry is presumed to reveal the developmental variability of the fish in polluted aquatic environments. In these habitats, high-level asymmetry develops, and these fish expend more energy to balance their growth than fish that are not under an impact. A total of 210 specimens of Acanthopagrus bifasciatus, A. latus and Sparidentex hasta were collected from the marine waters of Iraq in the northwest part of the Arabian Gulf. The asymmetry was calculated for the sagittal otolith characters of length and width. Otolith width has lower asymmetry than otolith length for the three sparid fish species investigated. An increase in the value of fluctuating asymmetry with fish length was observed. This could be a pertinent indicator of pollution in the habitat.

• MeSH
• ekosystém MeSH
• otolitová membrána * MeSH
• Perciformes * MeSH
• ryby MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The endocrine disruptor Bisphenol A (BPA), a widely employed molecule in plastics, has been shown to affect several biological processes in vertebrates, mostly via binding to nuclear receptors. Neurodevelopmental effects of BPA have been documented in vertebrates and linked to neurodevelopmental disorders, probably because some nuclear receptors are present in the vertebrate brain. Similarly, endocrine disruptors have been shown to affect neurodevelopment in marine invertebrates such as ascidians, mollusks or echinoderms, but whether invertebrate nuclear receptors are involved in the mode-of-action is largely unknown. In this study, we assessed the effect of BPA on larval brain development of the ascidian Phallusia mammillata. We found that BPA is toxic to P. mammillata embryos in a dose-dependent manner (EC50: 11.8μM; LC50: 21μM). Furthermore, micromolar doses of BPA impaired differentiation of the ascidian pigmented cells, by inhibiting otolith movement within the sensory vesicle. We further show that this phenotype is specific to other two bisphenols (BPE and BPF) over a bisphenyl (2,2 DPP). Because in vertebrates the estrogen-related receptor gamma (ERRγ) can bind bisphenols with high affinity but not bisphenyls, we tested whether the ascidian ERR participates in the neurodevelopmental phenotype induced by BPA. Interestingly, P. mammillata ERR is expressed in the larval brain, adjacent to the differentiating otolith. Furthermore, antagonists of vertebrate ERRs also inhibited the otolith movement but not pigmentation. Together our observations suggest that BPA may affect ascidian otolith differentiation by altering Pm-ERR activity whereas otolith pigmentation defects might be due to the known inhibitory effect of bisphenols on tyrosinase enzymatic activity.

• MeSH
• benzhydrylové sloučeniny chemie   toxicita   MeSH
• buněčná diferenciace účinky léků   MeSH
• chemické látky znečišťující vodu toxicita   MeSH
• embryo nesavčí účinky léků   MeSH
• fenoly chemie   toxicita   MeSH
• larva účinky léků   metabolismus   MeSH
• mozek cytologie   embryologie   MeSH
• organogeneze * účinky léků   MeSH
• otolitová membrána cytologie   účinky léků   MeSH
• pigmentace * účinky léků   MeSH
• pohyb buněk účinky léků   MeSH
• receptory pro estrogeny antagonisté a inhibitory   metabolismus   MeSH
• testy toxicity MeSH
• Urochordata cytologie   embryologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The role of Sox2 in neurosensory development is not yet fully understood. Using mice with conditional Islet1-cre mediated deletion of Sox2, we explored the function of Sox2 in neurosensory development in a model with limited cell type diversification, the inner ear. In Sox2 conditional mutants, neurons initially appear to form normally, whereas late- differentiating neurons of the cochlear apex never form. Variable numbers of hair cells differentiate in the utricle, saccule, and cochlear base but sensory epithelium formation is completely absent in the apex and all three cristae of the semicircular canal ampullae. Hair cells differentiate only in sensory epithelia known or proposed to have a lineage relationship of neurons and hair cells. All initially formed neurons lacking hair cell targets die by apoptosis days after they project toward non-existing epithelia. Therefore, late neuronal development depends directly on Sox2 for differentiation and on the survival of hair cells, possibly derived from common neurosensory precursors.

• MeSH
• delece genu MeSH
• myši transgenní MeSH
• myši MeSH
• neurogeneze fyziologie   MeSH
• sakulus a utrikulus cytologie   embryologie   MeSH
• transkripční faktory SOXB1 genetika   metabolismus   MeSH
• vláskové buňky cytologie   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH

This study presents, for the first time, a comprehensive dataset that documents the range of inter- and intraspecific otolith variation in aplocheiloid killifish, based on a total of 86 individuals representing five extant species of Nothobranchius PETERS, 1868, from East Africa: the sympatric pairs N. rubripinnis SEEGERS, 1986 and N. ruudwildekampi COSTA, 2009 (Eastern Tanzania), and N. orthonotus (PETERS, 1844) and N. furzeri JUBB, 1971 (Southern Mozambique), and two isolated populations of N. korthausae MEINKEN, 1973 (Eastern Tanzania). Otolith characters were analysed based on SEM images, and otolith morphometry was conducted using uni- and multivariate statistics. Two ancient clades of probably Early to Middle Miocene age in eastern Tanzania and southern Mozambique can be recognized based on otolith morphologies, which is consistent with previous work based on molecular data. The distinctive sulcus morphologies in the otoliths of sympatric species may be linked to species-specific hearing capabilities, perhaps constituting a case of character displacement in an area of secondary sympatry. The otoliths of the studied species of Nothobranchius are diagnostic at the species level, even in the case of closely related species diagnosable otherwise only by minor differences in coloration. The two populations of N. korthausae also displayed some differences in their otolith characters. The new data may facilitate future recognition of fossil species of Nothobranchius. As no fossil remains of extant aplocheiloid killifishes have yet been described, the discovery of fossil otoliths of Nothobranchius would significantly advance understanding of the evolutionary history of this interesting group of fishes.

• MeSH
• Cyprinodontidae anatomie a histologie   klasifikace   MeSH
• databáze faktografické MeSH
• druhová specificita MeSH
• fylogeneze MeSH
• otolitová membrána anatomie a histologie   MeSH
• zkameněliny anatomie a histologie   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• východní Afrika MeSH

• MeSH
• Adenoviridae MeSH
• genetické vektory MeSH
• modely nemocí na zvířatech MeSH
• regenerace MeSH
• sekvenční homologie MeSH
• vestibulární vláskové buňky MeSH

• Konspekt
• Patologie. Klinická medicína
• NLK Obory
• otorinolaryngologie
• NLK Publikační typ
• studie

Úvod: Testy rovnováhy jsou běžnou součástí neurologického a otorhinolaryngologického vyšetření. Cílem této studie bylo prozkoumat vliv vertikální a horizontální vizuální stimulace na posturální reflexy měřené kraniokorpografií, za účelem podrobného ověření účinnosti kontroly rovnováhy při narušení vizuálně-vestibulární integrity. Cíl: Cílem studie bylo zjistit vliv vizuální, horizontální a vertikální optokinetické a sinusoidální stimulace na posturální reflexy. Metodologie: Testována byla skupina 40 zdravých jedinců (20 žen, 20 mužů) ve věku 18–52 bez patologické otoneurologické anamnézy nebo příznaků. Za účelem zjištění poruch rovnováhy měřených kraniokorpografií během Rombergova testu byla aplikována horizontální a vertikální optokinetická a sinusoidální stimulace. Výsledky: Zjistili jsme, že vizuální stimulace (optokinetická a sinusodiální) v horizontální rovině vyvolaly silnější posturální poruchy než vizuální stimulace ve vertikální rovině. Jak horizontální, tak vertikální optokinetická stimulace vedla k větším longitudinálním výkyvům těla. Laterální vychýlení těla bylo lépe kontrolováno během vertikální stimulace. Autoři zjistili rozdíly v posturálních reflexech v závislosti na směru jak horizontální, tak vertikální vizuální stimulace. Kontrola rovnováhy byla lepší, byla-li optokinetická stimulace směřována doleva a dolů. Zvýšená intenzita vizuální stimulace (cílová velocita) rovnováhu nezhoršovala.

Introduction: Tests of balance are routine elements of neurological and otolaryngological examination. What follows is a general study of the effectiveness of balance control when visual-vestibular integrity is disturbed, conducted by means of ascertaining the influence of vertical and horizontal visual stimulation on postural reflexes as measured by craniocorpography. Goal: The purpose of the study was to observe the effect of visual, horizontal and vertical optokinetic and sinusoidal stimulation on postural reflexes. Material and method: A group of 40 healthy subjects (20 female, 20 male) aged 18–52 with no pathological otoneurologial history or signs was tested. Horizontal and vertical optokinetic and sinusoidal stimulation was administered in order to observe balance disturbances, as measured by craniocorpography in the course of a R omberg test. Results: It was revealed that visual stimulation (optokinetic and sinusoidal) in the horizontal plane induced stronger postural disturbances than visual stimulation in the vertical plane. Both horizontal and vertical optokinetic stimulation resulted in high longitudinal body sway. Lateral body displacement was better controlled during vertical visual disturbances. The authors observed that the differences in postural reflexes were dependent on the direction of both horizontal and vertical visual stimulation. Balance control was better when the optokinetic incitement was directed to the left and downward. Increased intensity of visual stimulus (target velocity) did not worsen balance.

• Klíčová slova
• kraniokorpografie, vizuální stimulace, otolity,
• MeSH
• antropometrie MeSH
• experimenty na lidech MeSH
• kineziologie aplikovaná MeSH
• lidé MeSH
• otolitová membrána MeSH
• poruchy zraku komplikace   MeSH
• postura těla fyziologie   MeSH
• posturální rovnováha fyziologie   MeSH
• rehabilitace MeSH
• statistika jako téma MeSH
• světelná stimulace metody   přístrojové vybavení   MeSH
• výzkumné techniky MeSH
• zraková percepce fyziologie   MeSH
• Check Tag
• lidé MeSH

The age structures of populations of African annual Nothobranchius spp. were examined for the first time. Daily increments in sagittal otoliths of Nothobranchius furzeri, Nothobranchius kadleci, Nothobranchius orthonotus and Nothobranchius rachovii from southern and central Mozambique were used for age determination. Four hypotheses were tested: (1) timing of hatching is consistent with the calendar onset of the rainy season, (2) hatching is synchronized within a population in a pool, (3) there is a difference in hatching date between geographical regions differing in mean total annual precipitation and (4) sympatric Nothobranchius spp. hatch at the same time. The results show that daily increment analysis represents an applicable method for age determination in Nothobranchius spp. Despite a significant positive relationship between age and size of fishes, a pronounced variation in fish size at an age precluded the use of fish size as a valid age marker. Timing of hatching was not consistent with the calendar onset of the rainy season. Interpopulation variability was observed in the degree of hatching date synchronization within a population. Hatching dates were relatively uniform in some populations, while there was considerable variability in others. Differences in timing of hatching date were found in only 1 of 2 years within the three regions investigated (Chefu, lower Limpopo and Sofala regions), each of which differed in mean total annual rainfall. The hatching dates of sympatric Nothobranchius spp. were marginally different, but further testing on a larger sample is needed for conclusive results.

• MeSH
• Cyprinodontidae fyziologie   MeSH
• otolitová membrána anatomie a histologie   MeSH
• roční období MeSH
• rozmnožování fyziologie   MeSH
• velikost těla fyziologie   MeSH
• zvířata MeSH
• Check Tag
• mužské pohlaví MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Mosambik MeSH

• MeSH
• kaménky komplikace   patofyziologie   MeSH
• krystalizace MeSH
• lidé MeSH
• medicína založená na důkazech MeSH
• nemoci vnitřního ucha komplikace   patofyziologie   MeSH
• otolitová membrána MeSH
• postura těla MeSH
• primární zdravotní péče metody   MeSH
• semicirkulární kanálky patofyziologie   MeSH
• sloučeniny vápníku MeSH
• směrnice pro lékařskou praxi jako téma MeSH
• společnosti lékařské MeSH
• techniky fyzikální terapie MeSH
• vertigo etiologie   patofyziologie   terapie   MeSH
• Check Tag
• lidé MeSH

Atypická instabilita, která nejeví známky charakteristické pro klinicky nejčastější rotační závrať, může být projevem některé z forem otolitové poruchy. Standardní funkční diagnostika vestibulárního aparátu vyšetřuje pouze funkce polokruhových kanálků, a proto pacienti s poruchou otolitů mohou být mylně vedeni pod hlavičkou funkčního onemocnění. Tento přehledový článek obsáhle shrnuje současný pohled na problematiku patofyziologie a symptomatologie otolitových poruch. Snahou autorů je vysvětlit nejběžnější subjektivní obtíže, jakož i typické nálezy při klinickém vyšetření a to vše při objasnění patofyziologie jednotlivých výpadků. Článek předkládá rovněž anatomicko-fyzíologický popis otolitových struktur a výčet onemocnění zahrnujících otolitové poruchy. Uvedené skutečnosti mají usnadnit diagnostiku onemocnění otolitových struktur.

Atypical instability without signs characteristic of clinically most frequent rotatory vertigo may manifest some form of otolith disturbance. Standard functional diagnostics of the vestibular apparatus examines only functions of semicircular canals, therefore patients with a disorder of otoliths can be misdiagnosed and considered as suffering from a functional disease. This article has summed up the present view of the problems of pathophysiology and symptomatology of otolith disorders. The authors have tried to explain the most common subjective difficulties as well as typical findings revealed in the course of clinical examinations, and to elucidate the pathophysiology of each deficit. There is also given the anatomico-physiological description of otolith structures and a list of diseases involving otolith disorders. The mentioned facts should facilitate the diagnostics of diseases affecting otolith structures.

• MeSH
• finanční podpora výzkumu jako téma MeSH
• lidé MeSH
• nervové dráhy MeSH
• otolitová membrána patofyziologie   patologie   MeSH
• patologický nystagmus patofyziologie   MeSH
• vertigo etiologie   patofyziologie   MeSH
• vestibulární aparát patofyziologie   MeSH
• vestibulární nemoci diagnóza   etiologie   MeSH
• Check Tag
• lidé MeSH