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In electroreceptive jawed vertebrates, embryonic lateral line placodes give rise to electrosensory ampullary organs as well as mechanosensory neuromasts. Previous reports of shared gene expression suggest that conserved mechanisms underlie electroreceptor and mechanosensory hair cell development and that electroreceptors evolved as a transcriptionally related "sister cell type" to hair cells. We previously identified only one transcription factor gene, Neurod4, as ampullary organ-restricted in the developing lateral line system of a chondrostean ray-finned fish, the Mississippi paddlefish (Polyodon spathula). The other 16 transcription factor genes we previously validated in paddlefish were expressed in both ampullary organs and neuromasts. Here, we used our published lateral line organ-enriched gene-set (arising from differential bulk RNA-seq in late-larval paddlefish), together with a candidate gene approach, to identify 25 transcription factor genes expressed in the developing lateral line system of a more experimentally tractable chondrostean, the sterlet (Acipenser ruthenus, a small sturgeon), and/or that of paddlefish. Thirteen are expressed in both ampullary organs and neuromasts, consistent with conservation of molecular mechanisms. Seven are electrosensory-restricted on the head (Irx5, Irx3, Insm1, Sp5, Satb2, Mafa and Rorc), and five are the first-reported mechanosensoryrestricted transcription factor genes (Foxg1, Sox8, Isl1, Hmx2 and Rorb). However, as previously reported, Sox8 is expressed in ampullary organs as well as neuromasts in a catshark (Scyliorhinus canicula), suggesting the existence of lineage-specific differences between cartilaginous and ray-finned fishes. Overall, our results support the hypothesis that ampullary organs and neuromasts develop via largely conserved transcriptional mechanisms, and identify multiple transcription factors potentially involved in the formation of electrosensory versus mechanosensory lateral line organs. [ABSTRACT FROM AUTHOR]

In electroreceptive jawed vertebrates, embryonic lateral line placodes give rise to electrosensory ampullary organs as well as mechanosensory neuromasts. Previous reports of shared gene expression suggest that conserved mechanisms underlie electroreceptor and mechanosensory hair cell development and that electroreceptors evolved as a transcriptionally related “sister cell type” to hair cells. We previously identified only one transcription factor gene, Neurod4, as ampullary organ-restricted in the developing lateral line system of a chondrostean ray-finned fish, the Mississippi paddlefish (Polyodon spathula). The other 16 transcription factor genes we previously validated in paddlefish were expressed in both ampullary organs and neuromasts. Here, we used our published lateral line organ-enriched gene-set (arising from differential bulk RNA-seq in late-larval paddlefish), together with a candidate gene approach, to identify 25 transcription factor genes expressed in the developing lateral line system of a more experimentally tractable chondrostean, the sterlet (Acipenser ruthenus, a small sturgeon), and/or that of paddlefish. Thirteen are expressed in both ampullary organs and neuromasts, consistent with conservation of molecular mechanisms. Seven are electrosensory-restricted on the head (Irx5, Irx3, Insm1, Sp5, Satb2, Mafa and Rorc), and five are the first-reported mechanosensory-restricted transcription factor genes (Foxg1, Sox8, Isl1, Hmx2 and Rorb). However, as previously reported, Sox8 is expressed in ampullary organs as well as neuromasts in a catshark (Scyliorhinus canicula), suggesting the existence of lineage-specific differences between cartilaginous and ray-finned fishes. Overall, our results support the hypothesis that ampullary organs and neuromasts develop via largely conserved transcriptional mechanisms, and identify multiple transcription factors potentially involved in the formation of electrosensory versus mechanosensory lateral line organs.

Highlights • Spatial preferences of Iberian barbel depended on non-uniform flow scenarios. • The relative importance of hydrodynamic variables varied between scenarios. • Near-wall regions were dominant in the spatial usage. • Vertical slot fishways using standard dimensions may produce adverse conditions when non-uniformity is not considered. Abstract Fish require access to multiple habitats to persist. Therefore, obstacles blocking a fish's volitional ability to move between habitats can lead to its decline. A common way of addressing this problem is the construction of fishways. The design criteria of fishways are based on steady, uniform flows with the assumption that the water levels remain the same across the fishway. However once constructed, fishways are fundamentally dynamic systems exhibiting different hydrodynamic scenarios. These scenarios are classified as uniform and non-uniform water level profiles and are driven by changes in the up- and downstream water levels caused by operational and hydrological variability. In this paper, we demonstrate the need to consider a wider range of fishway hydrodynamic scenarios for an integral assessment of fishways. To do this, the spatial distribution of Iberian barbel (Luciobarbus bocagei) in a full-scale model of a vertical slot fishway under three different hydrodynamic scenarios is investigated. Video tracking was used to analyze the fish's spatial distribution, and an acoustic Doppler velocimeter and lateral line probe were applied to characterize the local hydrodynamic conditions of each scenario. Spatial differences were tested using Syrjala's test and the relation with hydrodynamic variables analyzed by means of zero-inflated Poisson models. This study revealed three significant findings: 1) Fish made broader use of the fishway pool in scenarios with lower water drops, which are highly correlated with regions of overall lower turbulence and velocity magnitude. 2) The relative importance of physical variables varied between scenarios. Specifically, the protection offered by walls was found to be a determining factor in the spatial usage. 3) It is shown that a vertical slot fishway designed with the standard dimensions for fish passage under the assumption of uniform flow conditions may result in an adverse hydrodynamic environment for fish swimming under non-uniform conditions. [ABSTRACT FROM AUTHOR]

Background The production of a new lateral root from parental root primary tissues has been investigated extensively, and the most important regulatory mechanisms are now well known. A first regulatory mechanism is based on the synthesis of small peptides which interact ectopically with membrane receptors to elicit a modulation of transcription factor target genes. A second mechanism involves a complex cross-talk between plant hormones. It is known that lateral roots are formed even in parental root portions characterized by the presence of secondary tissues, but there is not yet agreement about the putative tissue source providing the cells competent to become founder cells of a new root primordium. Scope We suggest models of possible regulatory mechanisms for inducing specific root vascular cambium (VC) stem cells to abandon their activity in the production of xylem and phloem elements and to start instead the construction of a new lateral root primordium. Considering the ontogenic nature of the VC, the models which we suggest are the result of a comparative review of mechanisms known to control the activity of stem cells in the root apical meristem, procambium and VC. Stem cells in the root meristems can inherit various competences to play different roles, and their fate could be decided in response to cross-talk between endogenous and exogenous signals. Conclusions We have found a high degree of relatedness among the regulatory mechanisms controlling the various root meristems. This fact suggests that competence to form new lateral roots can be inherited by some stem cells of the VC lineage. This kind of competence could be represented by a sensitivity of specific stem cells to factors such as those presented in our models. [ABSTRACT FROM AUTHOR]

Highlights • Dairy cows demonstrate lateralised passing of a person situated in a lane, depending on their behaviour. • Cows passing on the right exited a crush faster, indicated behavioural arousal and rarely viewed the person while passing. • High yielding cows were more likely to pass on the right side, possibly because they are more anxious. Abstract Dairy cows’ emotional state can sometimes be inferred from their behaviour, for example previous studies have suggested that those passing a novel person to the right are more likely to be anxious than those passing to the left. We undertook two studies of cow behaviour as they passed a novel person, to validate these behaviours as emotional indicators, in addition to determining correlations to other indices of emotional state. Cows passing to the right were more likely to have a raised or tucked tail, sniff the ground, walk slowly and a faster exit when put in a crush, compared with those passing to the left, which had their ears held forwards. From a principal component analysis, it was determined that cows passing on the right side were also most likely to pass without turning their head towards the person, pass singly and defecate whilst passing. However, those passing to the left side were most likely to turn to look at the person and pass in pairs. Cows with high milk yields were more likely to pass on the right side. Measurements of side of passage were repeatable between experiments but those of ear position were not. It is concluded that side of passage past a person correlates with other behavioural indicators of the cow’s emotional state, with those passing to the right (i.e. left eye/right brain hemisphere) apparently more anxious. Evidence was also provided that high yielding cows are more anxious, as assessed by right side passage. With further validation, side of passage past a person could be developed as a simple measure of emotional state in dairy cows that can be conducted under field conditions. [ABSTRACT FROM AUTHOR]

The architecture of the cephalic lateral line canal system, with distinct lines for the supraorbital, infraorbital, and mandibular canals, is highly conserved among fish species. Because these canals lay on a cranial platform, the sensory input they receive is expected to change based on how flow interacts with the head and how the canal pores are spatially distributed. In this study, we explore how head width, a trait that can vary greatly between species and across ontogeny, affects flow sensing. We inserted pressure sensors into physical fish head models of varying widths (narrow, intermediate, and wide) and placed these models in steady and vortical flows. We measured sensory performance in terms of detecting flow parameters (flow speed, vortex shedding frequency, and cylinder diameter), sensitivity, (change in pressure gradient as a function of flow speed) and signal-to-noise ratio (strength of vortex shedding frequency with respect to background). Our results show that in all model heads the amount of hydrodynamic information was maximized at the anterior region regardless of what metric we used to evaluate the sensory performance. In addition, we discovered that all model heads had the highest signal-to-noise ratios (SNR) for vortices at the intermediate flow speeds but that each head width passively optimized the SNR for different sized vortices, which may have implications for refuge and prey seeking. Our results provide insight into the sensory ecology of fishes and has implications for the design of autonomous underwater vehicles. [ABSTRACT FROM AUTHOR]

Fishes inhabiting the deep sea are notable for the production of bioluminescence and specializations of their visual systems. However, they are also equipped with non-visual sensory systems that probably mediate critical behaviours as they do in other fishes, but they are not well-studied. The mechanosensory lateral line system of fishes in the order Stomiiformes, the largest and most diverse order of deep-sea fishes, was studied in detail in 28 species (in 17 of 52 genera, in all four stomiiform families) using several morphological methods. Some or all of the narrow cranial lateral line canals are partially reduced or absent in representatives of all genera examined. In addition, hundreds to thousands of small superficial neuromasts were found on the head and body in 17 species in 11 genera of sternoptychids, gonostomatids and stomiids. Reported here for the first time, this feature of the lateral line system would enhance sensitivity to the velocity component of water flows (probably of biotic origin) and is hypothesized to be an adaptation in the low-light environment of the deep sea. These observations require that we think beyond vision when considering the behaviour and sensory ecology of these critically important and globally distributed deep-sea fishes. [ABSTRACT FROM AUTHOR]

Summary: The mechanosensory lateral line system of fish is responsible for several functions such as balance, hearing, and orientation in water flow and is formed by neuromast receptor organs distributed on head, trunk and tail. Superficial and canal neuromasts can be distinguished for localization and morphological differences. Several information is present regarding the superficial neuromasts of zebrafish and other teleosts especially during larval and juvenile stages, while not as numerous data are so far available about the ultrastructural characteristics of the canal neuromasts in adult zebrafish. Therefore, the aim of this study was to investigate by transmission electron microscopy the ultrastructural aspects of cells present in the canal neuromasts. Besides the typical cellular aspects of the neuromast, different cellular types of hair cells were observed that could be identified as developing hair cells during the physiological turnover. The knowledge of the observed cellular types of the canal neuromasts and their origin could give a contribution to studies carried out on adult zebrafish used as model in neurological and non‐neurological damages, such as deafness and vestibular disorders. [ABSTRACT FROM AUTHOR]

A taxonomic review of the northwestern Pacific Ocean members of the Ostichthys japonicus complex (Holocentridae: Myripristinae), defined by 3.5 scale rows between the lateral line and spinous dorsal-fin base, recognized three valid species: Ostichthys alamai sp. nov., Ostichthys hypsipterygion Randall, Shimizu and Yamakawa 1982 and Ostichthys japonicus (Cuvier in Cuvier and Valenciennes 1829). Ostichthys alamai, based on 10 specimens (118-179 mm SL) from Panay Island, the Philippines and Sulawesi, Indonesia, is similar to O. hypsipterygion in having longitudinal rows of white spots laterally on the body, but has 17 or 18 (modally 17) pectoral-fin rays [vs. 15 or 16 (15) in the latter], the last dorsal-fin spine fused to the first dorsal-fin soft ray (vs. spine and ray separated), and no white blotch on the pectoral-fin base (vs. white blotch present). It differs from O. japonicus, also occurring in the Philippines, in having relatively longer dorsal- and anal-fin spines, a greater number of well-developed long spinules on the body scales, and rows of white spots laterally on the body (vs. generally absent). Detailed comparisons of O. alamai with other members of the complex are made, and revised diagnoses given for O. hypsipterygion and O. japonicus. Ostichthys sheni Chen, Shao and Mok 1990 and Holotrachys major Whitley 1950 are both regarded as junior synonyms of O. japonicus. [ABSTRACT FROM AUTHOR]

The neuromast is the morphological unit of the lateral line of fishes and is composed of a cluster of central sensory cells (hair cells) surrounded by support and mantle cells. Heavy metals exposure leads to disruption of hair cells within the neuromast. It is well known that the zebrafish has the ability to regenerate the hair cells after damage caused by toxicants. The process of regeneration depends on proliferation, differentiation and cellular migration of sensory and non-sensory progenitor cells. Therefore, our study was made in order to identify which cellular types are involved in the complex process of regeneration during heavy metals exposure. For this purpose, adult zebrafish were exposed to various heavy metals (Arsenic, cadmium and zinc) for 72 h. After acute (24 h) exposure, immunohistochemical localization of S100 (a specific marker for hair cells) in the neuromasts highlighted the hair cells loss. The immunoreaction for Sox2 (a specific marker for stem cells), at the same time, was observed in the support and mantle cells, after exposure to arsenic and cadmium, while only in the support cells after exposure to zinc. After chronic (72 h) exposure the hair cells were regenerated, showing an immunoreaction for S100 protein. At the same exposure time to the three metals, a Sox2 immunoreaction was expressed in support and mantle cells. Our results showed for the first time the regenerative capacity of hair cells, not only after, but also during exposure to heavy metals, demonstrated by the presence of different stem cells that can diversify in hair cells. [ABSTRACT FROM AUTHOR]

The purpose of this study was to determine whether women demonstrate decreased rate of torque development (RTD) of the hip and knee extensors and altered onset timing of the vastus lateralis and gluteus maximus during a drop-jump task when compared with men. On average, women demonstrated significantly lower normalized RTD of the hip extensors (women: 11.6 ± 1.3 MVT.s-1, men: 13.1 ± 0.9 MVT.s-1; p ≤ .01); however, there was no significant difference in knee extensor RTD. Women also demonstrated significantly earlier activation of their vastus lateralis (women: 206.0 ± 130.6 ms, men: 80.9 ± 69.6 ms; p ≤ .01) and gluteus maximus (women: 85.7 ± 58.6 ms, men: 54.5 ± 35.4 ms; p = .02). In both men and women, there was a significant negative correlation between the hip extensor RTD and the vastus lateralis electromyographic onset time (men: r = -.386, p = .046; women: r = -.531, p = .008). The study findings suggest that women may utilize a feedforward control strategy in which they activate their knee extensors earlier than men to compensate for deficits in hip extensor RTD. The impaired capacity to rapidly stabilize the hip and knee joints during dynamic maneuvers may contribute to the increased risk of anterior cruciate ligament injury observed in women. [ABSTRACT FROM AUTHOR]

Mormyrid fish rely on reafferent input for active electrolocation. Their electrosensory input consists of phase and amplitude information. These are encoded by differently tuned receptor cells within the Mormyromasts, A- and B-cells, respectively, which are distributed over the animal’s body. These convey their information to two topographically ordered medullary zones in the electrosensory lateral line lobe (ELL). The so-called medial zone receives only amplitude information, while the dorsolateral zone receives amplitude and phase information. Using both sources of information, Mormyrid fish can disambiguate electrical impedances. Where and how this disambiguation takes place is presently unclear. We here investigate phase-sensitivity downstream from the electroreceptors. We provide first evidence of phase-sensitivity in the medial zone of ELL. In this zone I-cells consistently decreased their rate to positive phase-shifts (6 of 20 cells) and increased their rate to negative shifts (11/20), while E-cells of the medial zone (3/9) responded oppositely to I-cells. In the dorsolateral zone the responses of E- and I-cells were opposite to those found in the medial zone. Tracer injections revealed interzonal projections that interconnect the dorsolateral and medial zones in a somatotopic manner. In summary, we show that phase information is processed differently in the dorsolateral and the medial zones. This is the first evidence for a mechanism that enhances the contrast between two parallel sensory channels in Mormyrid fish. This could be beneficial for impedance discrimination that ultimately must rely on a subtractive merging of these two sensory streams. [ABSTRACT FROM AUTHOR]

The duration of sleep varies dramatically between species, yet little is known about the genetic basis or evolutionary factors driving this variation in behavior. The Mexican cavefish, Astyanax mexicanus, exists as surface populations that inhabit rivers, and multiple cave populations with convergent evolution on sleep loss. The number of Hypocretin/Orexin (HCRT)-positive hypothalamic neurons is increased significantly in cavefish, and HCRT is upregulated at both the transcript and protein levels. Pharmacological or genetic inhibition of HCRT signaling increases sleep in cavefish, suggesting enhanced HCRT signaling underlies the evolution of sleep loss. Ablation of the lateral line or starvation, manipulations that selectively promote sleep in cavefish, inhibit hcrt expression in cavefish while having little effect on surface fish. These findings provide the first evidence of genetic and neuronal changes that contribute to the evolution of sleep loss, and support a conserved role for HCRT in sleep regulation. [ABSTRACT FROM AUTHOR]

Objective To investigate the effects of repetitive peripheral magnetic stimulation (rPMS) on the vastus lateralis (VL) in the early stage after hip replacement surgery. Methods Twenty-two patients who underwent hip replacement after proximal femur fracture were included in this study. After hip surgery, the experimental group was applied with 15 sessions of 10 Hz rPMS over the VL 5 times per week for 3 weeks, while the control group took sham stimulation. All patients were also given conventional physical therapy. The VL strength was measured with the root mean square (RMS) value of the VL with surface electromyography technique. The ratio of RMS values between fractured and unfractured legs and tandem stand test were used to assess standing balance. Usual gait speed was measured to evaluate gait function. Pain in two groups was assessed with visual analog scale (VAS). Results Both RMS value of the VL and the ratio of RMS values after rPMS were significantly improved (p<0.05). Also, tandem standing time and usual gait speed in rPMS group were dramatically increased (p<0.05). However, no significant difference in VAS was found between the two groups after 3 weeks. Conclusion rPMS on the VL improved muscle strength, standing balance and gait function in the early stage after hip surgery. Therefore, rPMS could be applied to patients who cannot take electrical stimulation due to pain and an unhealed wound. [ABSTRACT FROM AUTHOR]

The caddisfly species Micropterna lateralis is an abundant representative of limnephilids in intermittent streams. Yet, its basic life history characteristics and adaptations related to environmental factors, such as stream drying, are comparatively understudied. Here, we investigated larval growth and metabolic energy reserves (glycogen, triglycerides) through development in their natural habitat. We concentrated on the larval development because this period represents the important phase of energy accumulation necessary for growth, metamorphosis and embryogenesis. Besides larval physiology, female adults were studied in terms of ovarian maturation. Our results indicate that adult females lack an imaginal diapause, which is otherwise often observed in intermittent stream-inhabiting Limnephilidae. Further, M. lateralis is univoltine and exhibits a relatively fast larval development with five distinct instars, of which four are characterised here (instars II-V). Accrual of biomass occurs in final instars, where a high amount of glycogen is accumulated. Lipid concentrations, on the other hand, are kept constant in final stages and slightly lower than in preceding instars. This dominance of glycogen in final instars found in M. lateralis is highly unusual in insects and of potential adaptive significance for the species' ability to exploit intermittent habitats. [ABSTRACT FROM AUTHOR]

Lateralisation of cognitive function is a common phenomenon found throughout the animal kingdom. In fish, lateralisation is involved in visually mediated behaviours such as schooling, predator avoidance and foraging. This study sought to quantify visual laterality in yellow-eyed mullet (Aldrichetta forsteri), to determine visual asymmetries and the significance of lateralisation, and the factors which influence functional behaviours in schooling fish. Tank-based experiments investigated individual and population level lateralisation, schooling behaviour, and optic lobe asymmetry. Variation in direction and strength of lateralisation in individuals was found in juveniles, but at a population level significant bias was found in adults. Right eye biased fish had a larger right optic lobe than control fish. Strongly lateralised fish showed a tendency to occupy positions of safety within the school more frequently than control fish. In combination with observed differences in schooling behaviour, the possibility of ontogenetic plasticity in behavioural lateralisation and optic lobe morphology is suggested. [ABSTRACT FROM AUTHOR]

The introduction of non-native animals occasionally results in the co-introduction of their microbial symbionts or parasites. The trade of exotic pets and zoo animals has inadvertently introduced several parasitic species to countries where they are non-native. Both the presence of suitable native hosts and opportunity for dispersal determine whether these non-native species become naturalized. During our studies dealing with species of Herpomyces (Ascomycota, Laboulbeniomycetes), fungi that are exclusively ectoparasitic on cockroaches (Hexapoda, Blattodea), we make use of artificial colonies. Most of our specimens originate from pet stores and laboratory populations. Although they were originally intended for transmission studies, we discovered that some cockroaches from artificial colonies carried fruiting bodies of Herpomyces. We screened a total 292 cockroaches from 11 populations that we maintained after purchase. Sources were different pet stores, a toxicological laboratory, and a biological supply company. In eight populations, we found at least some Herpomyces-infected cockroaches. Parasite prevalence varied between 8.77% and 86.33%. Host associations were Blatta orientalis with Herpomyces stylopygae, Blattella germanica with H. ectobiae, Periplaneta americana with H. periplanetae, Phoetalia pallida with H. leurolestis, and Shelfordella lateralis with an undescribed species of Herpomyces. Apart from the new reports, host associations, and consequences for taxonomy (a new species based on morphological and molecular characters), we started to think about the geographic distributions of these fungi and how we, humans, shape them through spreading hosts and through international pet trade. We reviewed the currently known records of Herpomyces-associated cockroaches and host-parasite relationships. Based on the available data, on a global scale, at least half of the currently known species of Herpomyces are spread by globally invasive host species and through international pet trade. This indicates that the distribution and host range of these obscure and often unnoticed fungi are affected by human activities. [ABSTRACT FROM AUTHOR]

The trunk canal of fishes is contained within a series of lateral line ( LL) scales. To categorise LL scale structural types, and determine their distribution, an analysis of original data was undertaken using light and scanning electron microscopy in combination with a literature survey from over 1,000 species representative of most orders of bony fishes. Our categorisation of LL scales is based on the relationship between the tube, or ossified trunk canal segment, and associated scale. Tubular-Scalar LL scales consist of a distinguishable tube and elasmoid scale in scale pockets. Four types occur only in species with elasmoid scales. Integrated LL scales do not develop in scale pockets, and their tube is enclosed or extended by a non-elasmoid scale or spines. Integrated 1 and 2 LL scales co-occur with ganoid and calcidermoid scales, and Integrated 3 LL scales occur when common scales are absent or elasmoid. Tubular LL scales are tubes only, occurring mainly in scaleless species or with calcidermoid and elasmoid scales. Non-Tubular LL scales are composed only of a scale, co-occurring mainly with cycloid scales. There is consistency of LL scale type in many orders, families and genera and the presence of different types within taxa can be meaningful. [ABSTRACT FROM AUTHOR]

Coloration in three of four species of the genus Neurergus including N. microspilotus is characterized by the presence of yellow spots on a dark skin, but there is no available information about changes in spot configuration, speed of development and degree of association between melanophore-free region and the lateral line. In this study, spot numbers, spot circularity, spot size and spot asymmetry were studied during larval to adult growth in N. microspilotus during July 2012 to June 2015. The mean numbers of spots increased during the late larval stage till postmetamorphic period from 13.33 ± 3.77 to 22.53 ± 4.09 and reached 42.62 ± 4.06 in adults. At the same time, the extent of spots gradually decreased in size from 5.80 ± 1.00 to 3.57 ± 0.97 mm2 and reached 3.55 ± 1.42 mm2 in adults, but the spot circularity increased from 0.48 ± 0.23 to 0.78 ± 0.49 and reached 0.80 ± 0.15 in adults. In adults, the numbers, circularity, size and asymmetry of spots remain stable with little but non-significant changes during the study period. Histological study shows that formation of a melanophore-free region correlates with the development of the lateral line receptors. This study demonstrates that the effects of lateral line on chromatophores persist through middle larval stages but diminish as metamorphosis completes. [ABSTRACT FROM AUTHOR]

Abudefduf caudobimaculatus Okada and Ikeda 1939, having long been regarded as a junior synonym of Abudefduf vaigiensis (Quoy and Gaimard 1825), is herein redescribed as a valid species on the basis of the holotype and 77 additional specimens. Abudefduf caudobimaculatus can be distinguished from A. vaigiensis in having 11-13 (modally 12) dorsal-fin soft rays, 4 scale rows above the lateral line, 2½ scale rows between the middle of the spinous portion of the dorsal-fin base and lateral line, 3-4 (4) scale rows on the cheek, scales always present on the anteroventral region of the head, eleventh and last dorsal-fin spines and pectoral-fin length 15.5-18.4%, 17.1-20.6%, and 33.5-39.9% of SL, respectively, two black spots on the caudal-fin base, anteriormost bar descending to behind the pectoral-fin base, 0-1 tubed lateral-line scales on the fourth vertical bar, and third to seventh (usually fifth or sixth) dorsal-fin soft ray base at the anterior margin of the fourth vertical bar. Synonymies of A. vaigiensis are discussed with designations of lectotypes for Glyphisodon vaigiensis and Glyphisodon rahti. [ABSTRACT FROM AUTHOR]

Three new species of Acropoma are described from the Indian Ocean. These species have been identified as ' A. japonicum Günther 1859' by many authors, but clearly differ from A. japonicum in the shape and length of the luminous gland, counts of pectoral-fin rays and scales between first dorsal-fin base and lateral line, and other diagnostic characters. Acropoma heemstrai sp. nov. is described on the basis of 17 specimens (53.1-121.0 mm standard length: SL) collected from South Africa and Mozambique. It is distinguished from other congeners by its unique moderate Y-shaped luminous gland, extending from the throat to midway between the origins of the pelvic and anal fins, (luminous gland length 23.1-27.0% SL) and a pointed protrusion on the symphysis of lower jaw. Acropoma lacrima sp. nov. is described on the basis of 6 specimens (64.1-77.9 mm SL) collected from the Arabian Sea. Also, this species has been previously reported as ' A. argentistigma Okamoto and Ida 2002' from the Bay of Bengal. It is characterized by having a vertical line on the cheek, short U-shaped luminous gland (luminous gland length 15.0-16.0% SL), and weakly ctenoid and cycloid scales on the side of the body. Acropoma neglectum sp. nov. is described on the basis of 5 specimens (105.3-168.5 mm standard length: SL) collected from the Gulf of Aqaba, northern Red Sea. It is similar to A. japonicum in having a short U-shaped luminous gland, but differs in having a shorter luminous gland (12.0-13.4% SL vs. 17.0-20.8% SL in A. japonicum), 3 scales between first dorsal-fin base and lateral line (vs. 4 scales in A. japonicum), and 16-17 pectoral-fin rays [vs. 14-16 (modally 15) in A. japonicum]. [ABSTRACT FROM AUTHOR]

Background: Ecological research often requires monitoring of a specific individual over an extended period of time. To enable non-invasive re-identification, consistent external marking is required. Treefrogs possess lateral lines for crypticity. While these patterns decrease predator detection, they also are individual specific patterns. In this study, we tested the use of lateral lines in captive and wild populations of Dryophytes japonicus as natural markers for individual identification. For the purpose of the study, the results of visual and software assisted identifications were compared. Results: In normalized laboratory conditions, a visual individual identification method resulted in a 0.00 rate of false-negative identification (RFNI) and a 0.0068 rate of false-positive identification (RFPI), whereas Wild-ID resulted in RFNI = 0.25 and RFNI = 0.00. In the wild, female and male data sets were tested. For both data sets, visual identification resulted in RFNI and RFPI of 0.00, whereas the RFNI was 1.0 and RFPI was 0.00 with Wild-ID. Wild-ID did not perform as well as visual identification methods and had low scores for matching photographs. The matching scores were significantly correlated with the continuity of the type of camera used in the field. Conclusions: We provide clear methodological guidelines for photographic identification of D. japonicus using their lateral lines. We also recommend the use of Wild-ID as a supplemental tool rather the principal identification method when analyzing large datasets. [ABSTRACT FROM AUTHOR]

Lateral flow assays (LFAs) have promising potentials for point-of-care applications. Recently, many LFAs have been reported that are based on hybridization of oligonucleotide strands. Mostly, biotinylated capture DNAs are immobilized on the surface of a nitrocellulose membrane via streptavidin interactions. During the assay, stable colorful complexes get formed that are visible by naked eyes. Here, we present an inexpensive and unique design of LFA that applies unmodified oligonucleotides at capture lines. The presented LFA do not utilize streptavidin or any other affinity protein. We employ structural switch of molecular beacons (MB) in combination with base stacking hybridization (BSH) phenomenon. The unique design of the reported LFA provided high selectivity for target oligonucleotides. We validated potential applications of the system for detection of DNA mimics of two microRNAs in multiplex assays. [ABSTRACT FROM AUTHOR]

The lateral line system is a useful model for studying the embryonic and evolutionary diversification of different organs and cell types. In jawed vertebrates, this ancestrally comprises lines of mechanosensory neuromasts over the head and trunk, flanked on the head by fields of electrosensory ampullary organs, all innervated by lateral line neurons in cranial lateral line ganglia. Both types of sense organs, and their afferent neurons, develop from cranial lateral line placodes. Current research primarily focuses on the posterior lateral line primordium in zebrafish, which migrates as a cell collective along the trunk; epithelial rosettes form in the trailing zone and are deposited as a line of neuromasts, within which hair cells and supporting cells differentiate. However, in at least some other teleosts (e.g. catfishes) and all non-teleosts, lines of cranial neuromasts are formed by placodes that elongate to form a sensory ridge, which subsequently fragments, with neuromasts differentiating in a line along the crest of the ridge. Furthermore, in many non-teleost species, electrosensory ampullary organs develop from the flanks of the sensory ridge. It is unknown to what extent the molecular mechanisms underlying neuromast formation from the zebrafish migrating posterior lateral line primordium are conserved with the as-yet unexplored molecular mechanisms underlying neuromast and ampullary organ formation from elongating lateral line placodes. Here, we report experiments in an electroreceptive non-teleost ray-finned fish, the Mississippi paddlefish Polyodon spathula , that suggest a conserved role for Notch signaling in regulating lateral line organ receptor cell number, but potentially divergent roles for the fibroblast growth factor signaling pathway, both between neuromasts and ampullary organs, and between paddlefish and zebrafish. [ABSTRACT FROM AUTHOR]

Background: Decreases in patellofemoral pain symptoms with bracing treatment have been established; but, the mechanisms remain unclear. The purpose of this study was to determine the immediate and long-term effects of the patellar bracing on electromyography (EMG) activity of the Vastus Medialis (VM) and Lateralis (VL), Rectus Femoris, lateral Gastrocnemius, Biceps Femoris and Semitendinosus (ST) muscles during level walking.Methods: 12 eligible women aged 20-30 years with diagnosis of patellofemoral pain participated in the before and after study. Intervention consisted of 8 weeks of patellar bracing. First, patients were tested without brace, then with a brace, and finally eight weeks later without a brace. Surface EMG activation of the selected muscles during level walking was recorded.Results: After eight weeks of patellar bracing, EMG activity of VM muscle was significantly higher when compared to first session without brace (p=0.011) at mid-stance sub-phase. Additionally, EMG activity of ST muscle during first session with brace was significantly lower when compared to first session without brace at mid-stance sub-phase (without brace) (p=0.012). EMG activity of VM muscle after eight weeks of patellar bracing was significantly higher than the first session without brace at late stance and preswing sub-phase (p=0.013).Conclusion: Long-term wearing of patellar bracing increases EMG activity of VM during mid-stance and late stance and preswing sub-phases of gait and immediate effect of patellar brace is decrease of EMG activity of ST muscle during mid-stance. [ABSTRACT FROM AUTHOR]

Detection of motion is a feature essential to any living animal. In vertebrates, mechanosensory hair cells organized into the lateral line and vestibular systems are used to detect external water or head/body motion, respectively. While the neuronal components to detect these physical attributes are similar between the two sensory systems, the organizational pattern of the receptors in the periphery and the distribution of hindbrain afferent and efferent projections are adapted to the specific functions of the respective system. Here we provide a concise review comparing the functional organization of the vestibular and lateral line systems from the development of the organs to the wiring from the periphery and the first processing stages. The goal of this review is to highlight the similarities and differences to demonstrate how evolution caused a common neuronal substrate to adapt to different functions, one for the detection of external water stimuli and the generation of sensory maps and the other for the detection of self-motion and the generation of motor commands for immediate behavioral reactions. [ABSTRACT FROM AUTHOR]

The lateral line system and its innervation were examined in a generalized perch-like species, Lateolabrax japonicus (Percoidei incertae sedis), and compared with those in two species of Apogonidae ( Fowleria variegata in Apogonichthyini and Ostorhinchus doederleini in Ostorhinchini) characterized by proliferated superficial neuromasts (SNs) on the head, trunk lateral line scales and caudal fin. The total number of SNs differed greatly between the two groups, being 271 in the former, and 2,403 and 4,088 in the latter. The mandibular ramus (MDR) was extensively ramified in the head of the apogonids, with three additional branches that were absent in L. japonicus, innervating 1,117 SNs in F. variegata and 1,928 in O. doederleini. In the apogonids, the additional anterodorsal branch of the MDR coursed parallel to the buccal ramus anteriorly (on the interorbital space) and to the supratemporal ramus posteriorly (on the temporal region). The two parallel portions supplied numerous SN rows forming a characteristic crosshatch pattern, the branch and two rami distributing to transverse and longitudinal rows, respectively. In the two groups, the trunk lateral line scales each housed a canal neuromast (CN; partly replaced by an SN in F. variegata). In addition, one to four (in L. japonicus) and three to 55 (in the apogonids) SNs occurred on each lateral line scale, the pattern of SN innervation being identical in having two types of branches; one innervated a CN and SNs, and the other SN(s) only. The latter type extended only to a limited number of scales in L. japonicus, but to nearly all or all scales in the apogonids. Compared with F. variegata, branches of the respective types were more finely ramified with greater number of SNs in O. doederleini. [ABSTRACT FROM AUTHOR]

Presents the table of contents for this issue of the publication. [ABSTRACT FROM PUBLISHER]

Studies have shown that many behavioral decisions of fish are facilitated by the lateral line system which provides hydrodynamic information about the surrounding fluid. Inspired by the functionality of the system, a distributed pressure sensory system is developed. The system is intended for use on autonomous underwater vehicles to aid station keeping and accurate maneuvering by allowing the vehicle to react to the changes in the fluid environment before they result in body perturbation. The system can also be used for mission level decision making such as obstacle detection. This paper presents a prototype sensory system using differential, as opposed to absolute or gauge, pressure sensors as the sensing elements, which allows for higher measurement precision. Experimental tests are designed to characterize the system's ability to estimate the hydrodynamic force and to detect the presence of a wall. The hydrodynamic force estimated by the system is validated with an independent force measuring apparatus. The impending wall could also be detected by analyzing the pressure distribution obtained from the sensory system. Particularly, it is found that the wall distance and angle may be inferred by comparing the amplitude and phase of the Fourier components in the pressure distribution against those without the obstacle. [ABSTRACT FROM AUTHOR]

The anamniote lateral line system, comprising mechanosensory neuromasts and electrosensory ampullary organs, is a useful model for investigating the developmental and evolutionary diversification of different organs and cell types. Zebrafish neuromast development is increasingly well understood, but neither zebrafish nor Xenopus is electroreceptive and our molecular understanding of ampullary organ development is rudimentary. We have used RNA-seq to generate a lateral line-enriched gene-set from late-larval paddlefish (Polyodon spathula). Validation of a subset reveals expression in developing ampullary organs of transcription factor genes critical for hair cell development, and genes essential for glutamate release at hair cell ribbon synapses, suggesting close developmental, physiological and evolutionary links between non-teleost electroreceptors and hair cells. We identify an ampullary organ-specific proneural transcription factor, and candidates for the voltage-sensing L-type Cav channel and rectifying Kv channel predicted from skate (cartilaginous fish) ampullary organ electrophysiology. Overall, our results illuminate ampullary organ development, physiology and evolution. [ABSTRACT FROM AUTHOR]

The morphology and distribution of lateral line neuromasts vary between ecomorphological types of anuran tadpoles, but little is known about how this structural variability contributes to differences in lateral-line mediated behaviors. Previous research identified distinct differences in one such behavior, positive rheotaxis towards the source of a flow, in two tadpole species, the African clawed frog (Xenopus laevis; type 1) and the American bullfrog (Rana catesbeiana; type 4). Because these two species had been tested under different flow conditions, we re-evaluated these findings by quantifying flow-sensing behaviors of bullfrog tadpoles in the same flow field in which X. laevis tadpoles had been tested previously. Early larval bullfrog tadpoles were exposed to flow in the dark, in the presence of a discrete light cue, and after treatment with the ototoxin gentamicin. In response to flow, tadpoles moved downstream, closer to a side wall, and higher in the water column, but they did not station-hold. Tadpoles exhibited positive rheotaxis, but with long latencies, low to moderate accuracy, and considerable individual variability. This is in contrast to the robust, stereotyped station-holding and accurate rheotaxis of X. laevis tadpoles. The presence of a discrete visual cue and gentamicin treatment altered spatial positioning and disrupted rheotaxis in both tadpole species. Species differences in lateral-line mediated behaviors may reflect differences in neuromast number and distribution, life history, or perceptual salience of other environmental cues. [ABSTRACT FROM AUTHOR]

Manual tasks are an important goal-directed ability. In this EEG work, we studied how handedness affects the hemispheric lateralisation patterns during performance of visually-driven movements with either hand. The neural correlates were assessed by means of EEG coherence whereas behavioural output was measured by motor error. The EEG data indicated that left- and right-handers showed distinct recruitment patterns. These involved local interactions between brain regions as well as more widespread associations between brain systems. Despite these differences, brain-behaviour correlations highlighted that motor efficiency depended on left-sided brain regions across groups. These results suggest that skilled hand motor control relies on different neural patterns as a function of handedness whereas behavioural efficiency is linked with the left hemisphere. In conclusion, the present findings add to our understanding about principles of lateralised organisation as a function of handedness. [ABSTRACT FROM AUTHOR]

Exposure to aminoglycoside antibiotics can lead to the generation of toxic levels of reactive oxygen species (ROS) within mechanosensory hair cells of the inner ear that have been implicated in hearing and balance disorders. Better understanding of the origin of aminoglycoside-induced ROS could focus the development of therapies aimed at preventing this event. In this work, we used the zebrafish lateral line system to monitor the dynamic behavior of mitochondrial and cytoplasmic oxidation occurring within the same dying hair cell following exposure to aminoglycosides. The increased oxidation observed in both mitochondria and cytoplasm of dying hair cells was highly correlated with mitochondrial calcium uptake. Application of the mitochondrial uniporter inhibitor Ru360 reduced mitochondrial and cytoplasmic oxidation, suggesting that mitochondrial calcium drives ROS generation during aminoglycoside-induced hair cell death. Furthermore, targeting mitochondria with free radical scavengers conferred superior protection against aminoglycoside exposure compared with identical, untargeted scavengers. Our findings suggest that targeted therapies aimed at preventing mitochondrial oxidation have therapeutic potential to ameliorate the toxic effects of aminoglycoside exposure. [ABSTRACT FROM AUTHOR]

Fishes use multimodal signals during both inter- and intra-sexual displays to convey information about their sex, reproductive state, and social status. These complex behavioral displays can include visual, auditory, olfactory, tactile, and hydrodynamic signals, and the relative role of each sensory channel in these complex multi-sensory interactions is a common focus of neuroethology. The mechanosensory lateral line system of fishes detects near-body water movements and is implicated in a variety of behaviors including schooling, rheotaxis, social communication, and prey detection. Cobalt chloride is commonly used to chemically ablate lateral line neuromasts, thereby eliminating water-movement cues to test for mechanosensory-mediated behavioral functions. However, cobalt acts as a nonspecific calcium channel antagonist and could potentially disrupt function of all superficially located sensory receptor cells, including those for chemosensing. Here, we examined whether CoCl2 treatment used to ablate the lateral line system also impairs olfaction in three freshwater fishes, the African cichlid fish Astatotilapia burtoni, goldfish Carassius auratus, and the Mexican blind cavefish Astyanax mexicanus. To examine the impact of CoCl2 on the activity of peripheral receptors, we quantified DASPEI fluorescence intensity of the olfactory epithelium from fish exposed to control and CoCl2 solutions. In addition, we examined brain activation in olfactory processing regions of A. burtoni immersed in either control or cobalt solutions. All three species exposed to CoCl2 had decreased DASPEI staining of the olfactory epithelium, and in A. burtoni, cobalt treatment caused reduced neural activation in olfactory processing regions of the brain. To our knowledge this is the first empirical evidence demonstrating that the same CoCl2 treatment used to ablate the lateral line system also impairs olfactory function. These data have important implications for the use of CoCl2 in future research and suggest that previous studies using CoCl2 should be reinterpreted in the context of both impaired mechanoreception and olfaction. [ABSTRACT FROM AUTHOR]

Realistic simulation of the dynamic effects of walking pedestrians on structures is still a considerable challenge. This is mainly due to the inter- and intrasubject variability of humans and their bodies and difficult-to-predict loading scenarios, including multipedestrian walking traffic and unknown human-structure interaction (HSI) mechanisms. Over the past three decades, several attempts have been made to simulate walking HSI in the lateral direction. However, research into the mechanisms of this interaction in the vertical direction, despite its higher likelihood and critical importance, is fragmented and incoherent. It is, therefore, difficult to apply and codify. This paper critically reviews the efforts to date to simulate walking HSI in the vertical direction and highlights the key areas that need further investigation. [ABSTRACT FROM AUTHOR]

The ability to locate and discriminate water surface waves that impinge simultaneously from multiple directions was studied in the clawed frog, Xenopus laevis . Monofrequency waves of 5-30 Hz were presented from point sources at a distance of 10 cm from the frog, unless stated otherwise, and the animal's response turn towards the wave origin examined. Two-choice conditioning with two simultaneous frontal waves at; 90-degree inter-wave angle revealed discrimination thresholds lower than 1 Hz for 10- to 20-Hz source wave frequencies. Smaller inter-wave angles resulted in larger thresholds, and no discrimination was found below 40°. If a third wave was added from behind, the frequency discrimination of the two frontal waves deteriorated, with 18 Hz being discriminated from waves differing by at least 2.75 Hz. Subjects also discriminated between two simultaneous waves of equal frequency presented from differing distances. At; distance of 10 cm, the discrimination threshold was 0.95 cm. Thus, X. laevis is capable of discriminating source distances in an overlap on the basis of wave curvatures. The detection of source directions among four, six or eight waves of equal frequency and distance was investigated by measuring the angular distribution of the response turns. Turns were significantly more closely oriented towards sources than to intermediate directions. The orientation accuracy did not degrade with the number of waves. [ABSTRACT FROM AUTHOR]

We examine the evolution of sensory organ patterning in the lateral line system of fish. Based on recent studies of how this system develops in zebrafish, and on comparative analyses between zebrafish and tuna, we argue that the evolution of lateral line patterns is mostly determined by variations in the underlying developmental processes, independent of any selective pressure. Yet the development of major developmental innovations is so directly linked to their exploitation that it is hard not to think of them as selected for, i.e., adaptive. We propose that adaptation resides mostly in how the nervous system adjusts to new morphologies to make them functional, i.e., that species are neurally adapted to whatever morphology is provided to them by their own developmental program. We show that recent data on behavioral differences between cave forms (blind) and surface forms (eyed) of the mexican fish Astyanax fasciatus support this view, and we propose that this species might provide a unique opportunity to assess the nature of adaptation and of selection in animal evolution. [ABSTRACT FROM AUTHOR]

Purpose: Motor unit activity is coordinated between many synergistic muscle pairs but the functional role of this coordination for the motor output is unclear. The purpose of this study was to investigate the short-term modality of coordinated motor unit activity–the synchronized discharge of individual motor units across muscles within time intervals of 5ms–for the Vastus Medialis (VM) and Lateralis (VL). Furthermore, we studied the task-dependency of intermuscular motor unit synchronization between VM and VL during static and dynamic squatting tasks to provide insight into its functional role. Methods: Sixteen healthy male and female participants completed four tasks: Bipedal squats, single-leg squats, an isometric squat, and single-leg balance. Monopolar surface electromyography (EMG) was used to record motor unit activity of VM and VL. For each task, intermuscular motor unit synchronization was determined using a coherence analysis between the raw EMG signals of VM and VL and compared to a reference coherence calculated from two desynchronized EMG signals. The time shift between VM and VL EMG signals was estimated according to the slope of the coherence phase angle spectrum. Results: For all tasks, except for singe-leg balance, coherence between 15–80Hz significantly exceeded the reference. The corresponding time shift between VM and VL was estimated as 4ms. Coherence between 30–60Hz was highest for the bipedal squat, followed by the single-leg squat and the isometric squat. Conclusion: There is substantial short-term motor unit synchronization between VM and VL. Intermuscular motor unit synchronization is enhanced for contractions during dynamic activities, possibly to facilitate a more accurate control of the joint torque, and reduced during single-leg tasks that require balance control and thus, a more independent muscle function. It is proposed that the central nervous system scales the degree of intermuscular motor unit synchronization according to the requirements of the movement task at hand. [ABSTRACT FROM AUTHOR]

The lateral line system and its innervation were examined in the blind cavefish Astyanax mexicanus (Characidae) and compared with that in the eyed surface-dwelling form of the same species. In both forms, superficial neuromasts occurred on almost the entire surface of the body and caudal fin, the number in the blind form being greater on the head (831) and tail (511) than in the eyed form (531 and 251, respectively), but lower on the trunk (1,305 vs. 2,125). In the blind form, superficial neuromasts were greatly proliferated on the cheek and lower jaw, the mandibular ramus being extensively ramified, including an additional major ramule that was absent in the eyed form. In both forms, superficial neuromasts on the trunk were innervated by a number of dorsal and ventral ramules (roughly corresponding to the number of lateral line scales) derived from the lateral ramus. In both forms, canal neuromasts in the infraorbital and trunk lateral line canals were innervated by nerves without associated elements innervating superficial neuromasts. Accordingly, the lateral line scales each accommodated only a single canal neuromast. This lateral line scale condition was recognized as common in Characidae, being in sharp contrast to the condition in Cyprinidae (both included in Otophysa) in which the lateral line scales each had a vertical row of superficial neuromasts. [ABSTRACT FROM AUTHOR]

A new species of pycnogonid collected by the Chinese research vessel, R/V HY IV, during deep sea cruises to the South China Sea in 2013, is described. The new species, Hemichela nanhaiensis, obtained from more than 1300 m depth, is distinguished from the other two species in the genus by the characters of the chela dactylus with 12 denticulations on the inner margin and by the presence of taller tubercles on the lateral processes. [ABSTRACT FROM AUTHOR]

Fish must integrate information from multiple sensory systems to mediate adaptive behaviors. Visual, acoustic and chemosensory cues provide contextual information during social interactions, but the role of mechanosensory signals detected by the lateral line system during aggressive behaviors is unknown. The aim of this study was first to characterize the lateral line system of the African cichlid fish Astatotilapia burtoni and second to determine the role of mechanoreception during agonistic interactions. The A. burtoni lateral line system is similar to that of many other cichlid fishes, containing lines of superficial neuromasts on the head, trunk and caudal fin, and narrow canals. Astatotilapia burtoni males defend their territories from other males using aggressive behaviors that we classified as non-contact or contact. By chemically and physically ablating the lateral line system prior to forced territorial interactions, we showed that the lateral line system is necessary for mutual assessment of opponents and the use of non-contact fight behaviors. Our data suggest that the lateral line system facilitates the use of noncontact assessment and fight behaviors as a protective mechanism against physical damage. In addition to a role in prey detection, the diversity of lateral line morphology in cichlids may have also enabled the expansion of their social behavioral repertoire. To our knowledge, this is the first study to implicate the lateral line system as a mode of social communication necessary for assessment during agonistic interactions. [ABSTRACT FROM AUTHOR]

The article discusses the role of Amotl2a function, overproliferation, and final pattern of sensory organs in the lateral line primordium (LLP) to control tissue size in zebrafish.

Rheotaxis is a widespread behavior with many potential benefits for fish and other aquatic animals, yet the sensory basis of rheotaxis under different fluvial conditions is still poorly understood. Here, we examine the role that vision and the lateral line play in the rheotactic behavior of a stream-dwelling species (Mexican tetra, Astyanax mexicanus) under both rectilinear and turbulent flow conditions. Turbulence lowered the flow speed at which threshold levels of rheotactic performance were elicited, an effect that was independent of sensory condition. Compared to fish with access to visual information, fish without access exhibited cross-stream casting behaviors and a decrease in the accuracy with which they oriented upstream. Visual deprivation effects were independent of availability of lateral line information and whether flow was rectilinear or turbulent. Fish deprived of lateral line information exhibited no measureable deficits under any of the conditions of this study. This study indicates that rheotactic abilities persist in the absence of both vision and lateral line under both turbulent and non-turbulent conditions, but that turbulence enhances either the motivation or ability of fish to orient to slow currents. [ABSTRACT FROM AUTHOR]

We investigated the responses of medullary lateral line units of the rudd, Scardinius erythrophthalmus, to bulk water flow (7 cm s) and to water flow that contained vortices shed by an upstream half cylinder (diameter 1, 2, and 3 cm). Thirty-five percent of the medullary units either increased or decreased their discharge rate with the increasing cylinder diameter. In some units, the spike patterns revealed the vortex shedding frequency, i.e., in these units the amplitude of spike train frequency spectra was similar or identical to the vortex shedding frequency. [ABSTRACT FROM AUTHOR]

In this paper we propose a discrete in continuous mathematical model for the morphogenesis of the posterior lateral line system in zebrafish. Our model follows closely the results obtained in recent biological experiments. We rely on a hybrid description: discrete for the cellular level and continuous for the molecular level. We prove the existence of steady solutions consistent with the formation of particular biological structure, the neuromasts. Dynamical numerical simulations are performed to show the behavior of the model and its qualitative and quantitative accuracy to describe the evolution of the cell aggregate. [ABSTRACT FROM AUTHOR]

The study aimed to evaluate the stretch-induced changes in muscle architecture in different portions of the gastrocnemius medialis (GM) and lateralis (GL) muscles. The reliability and sensitivity of the measurements were also assessed. Fascicle length (FL) and pennation angle (PA) were calculated in the middle and distal portions of GM and GL at 0°, 10° and 20° of ankle dorsiflexion. At the same angles, passive torque ( T pass ), peak torque (pT) and myotendinous junction displacement of GM were determined. Stiffness was calculated at muscle–tendon unit (MTU), muscle and tendon level. After static stretching administration, T pass , pT and MTU stiffness decreased by 22%, 12% and 16%, respectively ( p < 0.05). Muscle and tendon stiffness decreased by 15% and 16% ( p < 0.05). Nevertheless, no changes in FL and PA occurred. The reliability of the approach was always very high (intraclass correlation coefficient > 0.90), with an adequate level of sensitivity. pT after static stretching was related to decreases in MTU, muscle and tendon stiffness, but not to alterations in muscle architecture. [ABSTRACT FROM AUTHOR]

When encountering a unidirectional flow, many fish exhibit an unconditioned orienting response known as rheotaxis. This multisensory behavior can reportedly involve visual, vestibular, tactile and lateral line cues. However, the precise circumstances under which different senses contribute are still unclear and there is considerable debate, in particular, about the contributions of the lateral line. In this study, we investigate the rheotactic behavior of blind cavefish under conditions of spatially non-uniform flow (a jet stream), which in theory, should promote reliance on lateral line cues. The behavior of individual lateral line enabled and disabled fish was videorecorded under IR light in a square arena that prevented streamwise biases and that contained a narrowjet streamin the centerof the tank. Where as the stream'speak velocity (8 cm s-1) declined very little in the streamwise direction, it declined steeply in the cross-stream direction (~3-4.5 cm s-1 cm-1). Lateral line enabled fish showed higher levels of orientation to the stream and its source (a 1-cm-wide nozzle) when in the central (jet stream) region of the tank compared with surrounding regions, where as lateral line disabled fish showedrandomorientations in all regions of the tank. The results of this study indicate that the spatial characteristics of flow play a role in determining the sensory basis of rheotaxis. [ABSTRACT FROM AUTHOR]