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Frontiers in Neuroscience 2015Although predator odors are ethologically relevant stimuli for rodents, the molecular pathways and contribution of some brain regions involved in predator odor...
Although predator odors are ethologically relevant stimuli for rodents, the molecular pathways and contribution of some brain regions involved in predator odor conditioning remain elusive. Inhibition of histone deacetylases (HDACs) in the dorsal hippocampus has been shown to enhance shock-induced contextual fear learning, but it is unknown if HDACs have differential effects along the dorso-ventral hippocampal axis during predator odor fear learning. We injected MS-275, a class I HDAC inhibitor, bilaterally in the dorsal or ventral hippocampus of mice and found that it had no effects on innate anxiety in either region. We then assessed the effects of MS-275 at different stages of fear learning along the longitudinal hippocampal axis. Animals were injected with MS-275 or vehicle after context pre-exposure (pre-conditioning injections), when a representation of the context is first formed, or after exposure to coyote urine (post-conditioning injections), when the context becomes associated with predator odor. When MS-275 was administered after context pre-exposure, dorsally injected animals showed enhanced fear in the training context but were able to discriminate it from a neutral environment. Conversely, ventrally injected animals did not display enhanced learning in the training context but generalized the fear response to a neutral context. However, when MS-275 was administered after conditioning, there were no differences between the MS-275 and vehicle control groups in either the dorsal or ventral hippocampus. Surprisingly, all groups displayed generalization to a neutral context, suggesting that predator odor exposure followed by a mild stressor such as restraint leads to fear generalization. These results may elucidate distinct functions of the dorsal and ventral hippocampus in predator odor-induced fear conditioning as well as some of the molecular mechanisms underlying fear generalization.
PubMed: 26441495
DOI: 10.3389/fnins.2015.00319 -
Parasites & Vectors Dec 2018Functional inference on the attachment of acanthocephalans has generally been drawn directly from morphology. However, performance of structures is often non-intuitive...
BACKGROUND
Functional inference on the attachment of acanthocephalans has generally been drawn directly from morphology. However, performance of structures is often non-intuitive and context-dependent, thus performance analysis should be included whenever possible to improve functional interpretation. In acanthocephalans, performance analysis of attachment is available only for Acanthocephalus ranae, a species that solely relies on the proboscis to attach. Here we compare body morphology and muscle arrangement in 13 species of Corynosoma, which use their spiny body as a fundamental holdfast. A basic performance analysis using live cystacanths of two representative species is also provided.
METHODS
Adults of 13 Corynosoma spp. were obtained from 11 marine mammal species. Specimens were cut and carefully cleaned to examine muscle arrangement through light and scanning electron microscopy. Live cystacanths of C. australe and C. cetaceum were selected for performance analysis. Video records of evagination-invagination cycles of the proboscis were obtained and analysed with a video editor.
RESULTS
The basic arrangement of proboscis retractors, trunk circular and longitudinal muscles, neck retractors and receptacle retractors, was conserved in all Corynosoma species. Interspecific variability was found in the relative development of disk muscles: minimum in C. enhydri, maximum in C. cetaceum; the distal insertion of the ventral neck retractor: ventro-lateral in C. cetaceum, C. hamannni and C. pseudohamanni and ventral in the other species; and the distal insertion of the receptacle retractors: more proximal in species with a longer hindtrunk. Performance analysis indicated striking similarities to that described for A. ranae except that (i) the foretrunk bends ventrally during the evagination-invagination cycles of the proboscis; (ii) disk muscles can flatten the tip of the foretrunk regardless of these cycles; and (iii) the receptacle bends ventrally and is driven to the hindtrunk by coordinated action of receptacle retractors.
CONCLUSIONS
Species of Corynosoma are able to use up to six holfast mechanisms. Attachment relies on a similar performance to that described for A. ranae. However, structural ventral bending of an inflated, spiny foretrunk, with a parallel re-arrangement of foretrunk muscles, have generated unexpected novel functions that make attachment extremely effective in species of Corynosoma. Interspecific variability in trunk shape and muscle arrangement grossly correlates with the rheological conditions each species experiences in their microhabitats within the gut of marine mammals.
Topics: Acanthocephala; Animals; Female; Helminthiasis, Animal; Host-Parasite Interactions; Male; Mammals; Microscopy, Electron, Scanning; Muscles; Seawater; Video Recording
PubMed: 30545426
DOI: 10.1186/s13071-018-3165-1 -
International Journal of Molecular... Jan 2018Paleo-colour scientists have recently made the transition from describing melanin-based colouration in fossil specimens to inferring life-history traits of the species... (Review)
Review
Paleo-colour scientists have recently made the transition from describing melanin-based colouration in fossil specimens to inferring life-history traits of the species involved. Two such cases correspond to counter-shaded dinosaurs: dark-coloured due to melanins dorsally, and light-coloured ventrally. We believe that colour reconstruction of fossils based on the shape of preserved microstructures-the majority of paleo-colour studies involve melanin granules-is not without risks. In addition, animals with contrasting dorso-ventral colouration may be under different selection pressures beyond the need for camouflage, including, for instance, visual communication or ultraviolet (UV) protection. Melanin production is costly, and animals may invest less in areas of the integument where pigments are less needed. In addition, melanocytes exposed to UV radiation produce more melanin than unexposed melanocytes. Pigment economization may thus explain the colour pattern of some counter-shaded animals, including extinct species. Even in well-studied extant species, their diversity of hues and patterns is far from being understood; inferring colours and their functions in species only known from one or few specimens from the fossil record should be exerted with special prudence.
Topics: Animals; Biological Evolution; Dinosaurs; Extinction, Biological; Fossils; Melanins; Pigmentation; Quantitative Trait, Heritable; Skin Pigmentation
PubMed: 29360744
DOI: 10.3390/ijms19020230 -
Cell Adhesion & Migration 2009During development, dorsal root ganglion (DRG) neurons extend their axons toward the dorsolateral part of the spinal cord and enter the spinal cord through the dorsal... (Review)
Review
During development, dorsal root ganglion (DRG) neurons extend their axons toward the dorsolateral part of the spinal cord and enter the spinal cord through the dorsal root entry zone (DREZ). After entering the spinal cord, these axons project into the dorsal mantle layer after a 'waiting period' of a few days. We revealed that the diffusible axonal guidance molecule netrin-1 is a chemorepellent for developing DRG axons. When DRG axons orient themselves toward the DREZ, netrin-1 proteins derived from the ventral spinal cord prevent DRG axons from projecting aberrantly toward the ventral spinal cord and help them to project correctly toward the DREZ. In addition to the ventrally derived netrin-1, the dorsal spinal cord cells adjacent to the DREZ transiently express netrin-1 proteins during the waiting period. This dorsally derived netrin-1 contributes to the correct guidance of DRG axons to prevent them from invading the dorsal spinal cord. In general, there is a complete lack of sensory axonal regeneration after a spinal cord injury, because the dorsal column lesion exerts inhibitory activities toward regenerating axons. Netrin-1 is a novel candidate for a major inhibitor of sensory axonal regeneration in the spinal cord; because its expression level stays unchanged in the lesion site following injury, and adult DRG neurons respond to netrin-1-induced axon repulsion. Although further studies are required to show the involvement of netrin-1 in preventing the regeneration of sensory axons in CNS injury, the manipulation of netrin-1-induced repulsion in the CNS lesion site may be a potent approach for the treatment of human spinal injuries.
Topics: Animals; Axons; Humans; Mice; Nerve Growth Factors; Netrin-1; Regeneration; Signal Transduction; Spinal Cord; Tumor Suppressor Proteins
PubMed: 19262170
DOI: 10.4161/cam.3.2.7837 -
Neuroscience 1990Peptidergic fibers in the globus pallidus of the monkey appear in the morphological form referred to as woolly fibers. These fibers are composed of a dense plexus of...
Peptidergic fibers in the globus pallidus of the monkey appear in the morphological form referred to as woolly fibers. These fibers are composed of a dense plexus of thin beaded axons which ensheath an unstained central core. Such structures are not confined to the globus pallidus, but are also present in the bed nucleus of the stria terminalis, the hypothalamus, the dorsal part of the amygdala, and ventrally in the basal forebrain. The present study describes the relationship between projections from the rostral and ventral striatum and the enkephalin- and substance P-positive woolly fibers. Following injections of either tritiated amino acids or the lectin Phaseolus vulgaris-leucoagglutinin in the ventral striatum, anterogradely labeled fibers and terminals in the forebrain were visualized simultaneously with enkephalin- or substance P immunoreactivity in the same tissue section in order to determine: (i) the extent to which the woolly fiber distribution represents striatal output systems; (ii) whether woolly fibers can be considered as a marker for the entire striatal forebrain projection; and (iii) whether enkephalin and substance P are involved differentially in distinct ventral striatopallidal pathways. Phaseolus vulgaris-leucoagglutinin labeling is seen in the globus pallidus and adjacent structures either as single, beaded fibers or in a profile strikingly similar to that of woolly fibers. In tissue sections treated for a double immunohistochemical protocol, following which the Phaseolus vulgaris-leucoagglutinin-immunoreactive fibers turn black and the peptidergic woolly fibers brown; many of the lectin-positive fibers are seen to enter the peptide-positive woolly fiber plexus. Likewise, following the injections with tritiated amino acids in the ventral striatum, coarse structures that have dimensions resembling those of the woolly fibers are identified. In sections immunohistochemically stained and subsequently treated for autoradiography, peptide-positive woolly fibers can be identified underlying the silver grains. In sections stained for both peptide immunoreactivity and tracer substances, enkephalin or substance P-positive woolly fibers are present in all pallidal regions that receive ventral striatal input. However, the ventral striatum also sends fibers to the hypothalamus, bed nucleus of the stria terminalis, the dorsal part of the amygdala, the septum, the preoptic area, and other areas of the basal forebrain. In these nuclei the peptide-positive woolly fiber distribution is less extensive than the terminal labeling. The distribution of substance P-positive fibers in the subcommissural pallidal region is more limited than the distribution of enkephalinergic fibers.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Animals; Brain; Corpus Striatum; Efferent Pathways; Enkephalins; Female; Macaca mulatta; Nerve Fibers; Organ Specificity; Phytohemagglutinins; Substance P
PubMed: 1708114
DOI: 10.1016/0306-4522(90)90271-5 -
Frontiers in Cell and Developmental... 2022The folding of two-dimensional epithelial sheets into specific three-dimensional structures is a fundamental tissue construction mechanism in animal development. A...
The folding of two-dimensional epithelial sheets into specific three-dimensional structures is a fundamental tissue construction mechanism in animal development. A common mechanism that mediates epithelial folding is apical constriction, the active shrinking of cell apices driven by actomyosin contractions. It remains unclear whether cells outside of the constriction domain also contribute to folding. During mesoderm invagination, ventrally localized mesoderm epithelium undergoes apical constriction and subsequently folds into a furrow. While the critical role of apical constriction in ventral furrow formation has been well demonstrated, it remains unclear whether, and if so, how the laterally localized ectodermal tissue adjacent to the mesoderm contributes to furrow invagination. In this study, we combine experimental and computational approaches to test the potential function of the ectoderm in mesoderm invagination. Through laser-mediated, targeted disruption of cell formation prior to gastrulation, we found that the presence of intact lateral ectoderm is important for the effective transition between apical constriction and furrow invagination in the mesoderm. In addition, using a laser-ablation approach widely used for probing tissue tension, we found that the lateral ectodermal tissues exhibit signatures of tissue compression when ablation was performed shortly before the onset of mesoderm invagination. These observations led to the hypothesis that in-plane compression from the surrounding ectoderm facilitates mesoderm invagination by triggering buckling of the mesoderm epithelium. In support of this notion, we show that the dynamics of tissue flow during mesoderm invagination displays characteristic of elastic buckling, and this tissue dynamics can be recapitulated by combining local apical constriction and global compression in a simulated elastic monolayer. We propose that mesoderm invagination is achieved through epithelial buckling jointly mediated by apical constriction in the mesoderm and compression from the neighboring ectoderm.
PubMed: 35547820
DOI: 10.3389/fcell.2022.867438 -
Advances in Clinical and Experimental... Nov 2018Interactions within the musculoskeletal system have been investigated and confirmed in numerous studies.
BACKGROUND
Interactions within the musculoskeletal system have been investigated and confirmed in numerous studies.
OBJECTIVES
Since there are no standard values for the posture of healthy persons, this study attempts to define reference values for the upper body posture in healthy men.
MATERIAL AND METHODS
A 3-dimensional back scan was performed to quantify the upper back posture while habitually standing. Tolerance regions for habitual posture were calculated, including the upper and lower limit for 95% of all values. Furthermore, the left and right limit of the confidence interval (CI) was carried out. Group differences were tested by using the t-test or the Wilcoxon-Mann-Whitney U test.
RESULTS
Height, weight and body mass index (BMI) of the participants were comparable to those of the average young German males. The spinal column was marginally twisted to the right. The spinal curves, defined by the thoracic or lumbar flexion angle, and the kyphosis and lordosis angle, indicated that the angle in the thoracic spine area was larger than that in the lumbar region. Consequently, a more kyphotic posture was observed in the sagittal plane. The habitual posture was slightly scoliotic, with a rotational component (scapular depression left, right scapula marginally located more dorsally, high state of pelvic left, iliac left further rotated posteriorly and simultaneously tilted further ventrally). No significant difference between right and left-handed persons could be proven.
CONCLUSIONS
Video raster stereography is a suitable method to measure the 3-dimensional back surface. Using this method for healthy young men, we observed that they had an almost ideally balanced posture with minimal ventral body inclination and a marginal scoliotic deviation. The normal values allow a better comparison of data between different studies of body posture.
Topics: Adult; Back; Humans; Kyphosis; Lordosis; Lumbosacral Region; Male; Posture; Reference Values; Spine
PubMed: 30048053
DOI: 10.17219/acem/70669 -
The Journal of Experimental Medicine Feb 1927The experiments recorded show that the skin involved in the zone of inflammation produced by the endodermal injection of virulent living erysipelas streptococci into...
The experiments recorded show that the skin involved in the zone of inflammation produced by the endodermal injection of virulent living erysipelas streptococci into rabbits becomes, after the lesion has healed, partially but not completely resistant to subsequent infection with the homologous organism. In the majority of experiments the lesion resulting from the first endodermal injection spread downward, i.e., ventrally, to the site of needle puncture forming an oval or elongated inflammatory zone. Subsequent injections of the same strain into the skin beyond and ventral to the apparent edge of the lesion showed that these areas in the supposed direction of the lymph flow likewise became resistant but not quite to the same degree as in the inflammatory area. The contiguous areas above, behind, and in front of the healed lesion exhibited only a very mild degree of resistance. The other side of the rabbit where no previous injections had been made reacted as did the normal skin. Repeated injections on the same side bring about diminishing local reaction until there is almost no lesion following the injection of the standard skin dose. Thus there is a gradual spread of skin resistance on the inoculated side, whereas the non-injected side of the rabbit reacts normally. Finally, however, after many injections over relatively long periods the non-injected side becomes resistant, but at this time, there is evidence of general humoral immunity as shown by the presence of agglutinins and antitoxin in the blood. The local resistance is apparently not entirely specific, for the areas with the previous lesion and ventral to it become more resistant to another strain of beta hemolytic streptococcus, though in less degree, and to a virulent strain of Staphylococcus aureus to a still less degree. The most plausible explanation of the spread of the local immunity ventrally is that the streptococci follow the lymph channels. Indeed, in human erysipelas, the organisms are recovered by cutipuncture as far as 3 cm. beyond the advancing edge of the lesion where there is no gross evidence of inflammation. This aspect of local immunity will be considered in subsequent publications. The skin of the rabbit involved in the inflammatory reaction following the endodermal injection of living streptococci becomes resistant to subsequent injection of the homologous strain and of other strains of erysipelas streptococci which are not immunologically identical. The local immune areas are resistant but not to the same degree to a strain of hemolytic streptococci isolated from follicular tonsillitis and to a virulent Staphylococcus aureus. The areas contiguous to the local lesion but outside the apparent boundary of inflammation become more resistant to subsequent injection. But the regions ventral to those areas become more resistant than those dorsal, anterior, or posterior to the inflammatory zone. The skin on the non-injected side of the rabbit becomes resistant pari passu with the development of humoral immunity.
PubMed: 19869261
DOI: 10.1084/jem.45.3.411 -
BioRxiv : the Preprint Server For... Jun 2023Cranial neural crest (CNC) cells are induced at the border of the neural plate by a combination of FGF, Wnt, and BMP4 signaling. CNC then migrate ventrally and invade...
Cranial neural crest (CNC) cells are induced at the border of the neural plate by a combination of FGF, Wnt, and BMP4 signaling. CNC then migrate ventrally and invade ventral structures where they contribute to craniofacial development. Here we show that a non-proteolytic ADAM, Adam11, originally identified as a putative tumor suppressor binds to proteins of the Wnt and BMP4 signaling pathway. Mechanistic studies concerning these non-proteolytic ADAM lack almost entirely. We show that Adam11 positively regulates BMP4 signaling while negatively regulating β-catenin activity. By modulating these pathways, Adam11 controls the timing of neural tube closure and the proliferation and migration of CNC. Using both human tumor data and mouse B16 melanoma cells, we further show that ADAM11 levels similarly correlate with Wnt or BMP4 activation levels. We propose that ADAM11 preserve naïve cells by maintaining low Sox3 and Snail/Slug levels through stimulation of BMP4 and repression of Wnt signaling, while loss of ADAM11 results in increased Wnt signaling, increased proliferation and early epithelium to mesenchyme transition.
PubMed: 37398217
DOI: 10.1101/2023.06.13.544797 -
Molecular Imaging and Biology Oct 2021Many preclinical cancer studies use mice with varied phenotypes to monitor tumor treatment. We compared survival and optical imaging characteristics of strains with...
BACKGROUND
Many preclinical cancer studies use mice with varied phenotypes to monitor tumor treatment. We compared survival and optical imaging characteristics of strains with varied coat colors harboring luciferase-expressing disseminated lymphoma.
RESULTS
Luciferase-expressing lymphoma cells (Raji-luc) were injected via tail vein into severe combined immunodeficient (SCID) and Rag2-IL2rg (R2G2) mice, and survival was tracked. Tumor signals were obtained by imaging ventral and dorsal aspects of mice. Signal attenuation by isolated mouse pelts was measured in vitro. R2G2 mice had decreased survival compared to SCID mice (17 vs. 32 days, p<0.001) despite similar bioluminescence signal when mice were imaged dorsally (p=0.37). However, signal was 17.3-fold higher in R2G2 mice compared to SCID (p<0.001) when imaged ventrally. Isolated dark R2G2 dorsal pelts attenuated signal more than ventral pelts when placed over cells in vitro.
CONCLUSIONS
Mouse pelt color and imaging aspect are critical considerations for quantifying bioluminescent tumor signal, and the R2G2 mouse strain may prove useful for preclinical targeted therapy studies.
Topics: Animals; Cell Line; Disease Models, Animal; Female; Hair; Luminescent Measurements; Lymphoma; Mice; Mice, SCID; Mice, Transgenic; Radiotherapy; Skin Pigmentation
PubMed: 33830414
DOI: 10.1007/s11307-021-01594-0