Developmental variability channels mouse molar evolution

Do developmental systems preferentially produce certain types of variation that orient phenotypic evolution along preferred directions? At different scales, from the intra-population to the interspecific, the murine first upper molar shows repeated anterior elongation. Using a novel quantitative approach to compare the development of two mouse strains with short or long molars, we identified temporal, spatial and functional differences in tooth signaling center activity, that arise from differential tuning of the activation-inhibition mechanisms underlying tooth patterning. By tracing their fate, we could explain why only the upper first molar reacts via elongation of its anterior part. Despite a lack of genetic variation, individuals of the elongated strain varied in tooth length and the temporal dynamics of their signaling centers, highlighting the intrinsic instability of the upper molar developmental system. Collectively, these results reveal the variational properties of murine molar development that drive morphological evolution along a line of least resistance.

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Germinal center activity and B cell maturation promote protective antibody responses against Plasmodium pre-erythrocytic infection

10.1101/2021.09.10.459481 ◽

2021 ◽

Author(s):

Ganesh Ram R. Visweswaran ◽

Kamalakannan Vijayan ◽

Ramyavardhanee Chandrasekaran ◽

Olesya Trakhimets ◽

Samantha L. Whiteside ◽

...

Keyword(s):

B Cell ◽

Germinal Center ◽

Antibody Responses ◽

Cell Maturation ◽

Mouse Strains ◽

Specific Class ◽

Memory B Cell ◽

Protective Antibody ◽

B Cell Maturation ◽

Center Activity

AbstractBlocking Plasmodium, the causative agent of malaria, at the asymptomatic pre-erythrocytic stage would abrogate disease pathology and prevent transmission. Rodent-infectious species of Plasmodium such as P. yoelii (Py) serve as key tools to study vaccine efficacy and disease biology in immune-competent experimental animals. Here we evaluated the differences in vaccine-elicited humoral immunity in two widely used, and vastly diverged, inbred mouse strains, BALB/cJ and C57BL/6J, and identified immunological factors associated with protection. We vaccinated with Py circumsporozoite protein (CSP), the major surface antigen on the sporozoite, and evaluated protective efficacy after mosquito bite challenge. Vaccination achieved 60% sterile protection and otherwise delayed blood stage patency in BALB/cJ mice, whereas; all C57BL/6J mice were infected similar to controls. Interestingly, protection was mediated by antibodies, and could be passively transferred from immunized BALB/cJ mice into naïve C57BL/6J. Dissection of the underlying immunological features of protection revealed early deficits in antibody titers and polyclonal avidity in C57BL/6J mice. Additionally, PyCSP-vaccination in BALB/cJ induced a significantly higher proportion of antigen-specific B-cells and class-switched memory B-cell (MBCs) populations than in C57BL/6J mice. Strikingly, C57BL/6J mice also had markedly fewer germinal center experienced, CSP-specific class-switched MBCs compared to BALB/cJ mice. Analysis of the IgG γ chain repertoires by next generation sequencing in PyCSP-specific memory B-cell repertoires also revealed higher somatic hypermutation rates in BALB/cJ mice than in C57BL/6J mice. These findings indicate that BALB/cJ mice achieved higher levels of B cell maturation in response to vaccination with PyCSP, which likely enabled the development of protective antibody responses. Overall, our study indicates that germinal center activity and B cell maturation are key processes in the development of vaccine-elicited protective antibodies against CSP.

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Temporal and spatial dynamic of suspended sediments fluxes and sources and morphological evolution of the bed in the middle Loire river

10.5194/egusphere-egu21-15401 ◽

2021 ◽

Author(s):

Brahim Hichem Belbal ◽

Nicole Goutal ◽

Germain Antoine ◽

Olivier Cerdan

Keyword(s):

Power Plants ◽

River Flow ◽

Temporal Dynamics ◽

Morphological Evolution ◽

Suspended Sediments ◽

Second Phase ◽

Temporal Dynamic ◽

Massif Central ◽

Catchment Areas ◽

Loire River

<p>The middle Loire riverbed, after its confluence with Allier, is characterised by a morphology of alternate bars more or less vegetated and possesses riverbank flood protections. The suspended particulate matter (SPM) fluxes are therefore originated from these two catchment areas that drain the eastern and southern parts of the Massif Central. The temporal dynamics of the SPM fluxes are very variable, both on an interannual scale and on the scale of a flood event. Furthermore, SPM fluxes also present high spatial heterogeneities as they are governed by complex processes of production (erosion) and transfer (storage/remobilisation). The Loire river plays an important role in supporting the French energy production by providing cooling water to several Nuclear Power Plants (NPP). However, the cooling systems of the NPPs on the middle Loire are exposed to the risk of silting. In order to ensure a safe management of water intakes and prevent the industrial risks arising from sediment transport, it is therefore imperative to understand the spatio-temporal dynamic of sediment production and transfer.</p><p>In this context, the objective of this thesis work is to provide keys to improve sediment management of the river between the two NPPs of Belleville and Dampierre. In a first place, the river flow and SPM data available at the upstream NPP of Belleville will be analysed in order to understand the temporal variations of the incoming SPM fluxes. In a second phase, a soil erosion and hydrological model will be implemented to understand the production processes in the upstream catchments. This second part will allow to determine the interactions of the SPM inputs in the river with the morphodynamics of the bed of the Loire between the two stations. We will present the methodology that has been designed to apprehend these two phases and the first results of the river SPM temporal dynamic at the Belleville NPP station.</p>

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Developmental variability drives mouse molar evolution along an evolutionary line of least resistance

10.1101/818484 ◽

2019 ◽

Author(s):

Luke Hayden ◽

Katerina Lochovska ◽

Marie Sémon ◽

Sabrina Renaud ◽

Marie-Laure Delignette-Muller ◽

...

Keyword(s):

Developmental Biology ◽

Temporal Dynamics ◽

Morphological Variability ◽

Evolutionary Developmental Biology ◽

Lineage Tracing ◽

Small Scale ◽

Phenotypic Change ◽

Developmental Variation ◽

Upper Molar ◽

Lower Molar

AbstractDevelopmental systems may preferentially produce certain types of variation and, thereby, bias phenotypic evolution. This is a central issue in evolutionary developmental biology, albeit somewhat understudied. Here we focus on the shape of the first upper molar which shows a clear, repeated tendency for anterior elongation at different scales from within mouse populations to between species of the Mus genus. In contrast, the lower molar displays more evolutionary stability. We compared upper and lower molar development of mouse strains representative of this fine variation (DUHi: elongated molars and FVB: short molars). Using a novel quantitative approach to examine small-scale developmental variation, we identified temporal, spatial and functional differences in tooth signaling centers between the two strains, likely due to different tuning of the activation-inhibition mechanisms ruling signaling center patterning. Based on the spatio-temporal dynamics of signaling centers and their lineage tracing, we show an intrinsic difference in the fate of signaling centers between lower and upper jaw of both strains. This can explain why variations in activation-inhibition parameters between strains are turned into anterior elongation in the upper molar only. Finally, although the “elongated” DUHi strain was inbred, first molar elongation was variable in adults, and we found high levels of intra-strain developmental variation in upper molar development. This is consistent with the inherent developmental instability of the upper molar system enabling the morphological variability of the tooth phenotype.In conclusion, we have uncovered developmental properties that underlie the molar’s capacity for repeated phenotypic change, or said differently, that underlie a “line of least resistance”. By focusing on the developmental basis of fine phenotypic variation, our study also challenges some common assumptions and practices in developmental and evolutionary developmental biology.

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How to make a protostome

Invertebrate Systematics ◽

10.1071/is11041 ◽

2012 ◽

Vol 26 (1) ◽

pp. 25 ◽

Cited By ~ 16

Author(s):

Claus Nielsen

Keyword(s):

Adult Stage ◽

Morphological Evolution ◽

Anterior Part ◽

Nerve Ring ◽

Cerebral Ganglia ◽

New Information ◽

Planktotrophic Larvae ◽

Living Organisms ◽

Almost All ◽

Apical Ganglion

The origin and radiation of the major metazoan groups can be elucidated by phylogenomic studies, but morphological evolution must be inferred from embryology and morphology of living organisms. According to the trochaea theory, protostomes are derived from a holoplanktonic gastraea with a circumblastoporal ring of downstream-collecting compound cilia (archaeotroch) and a nervous system comprising an apical ganglion and a circumblastoporal nerve ring. The pelago-benthic life cycle evolved through the addition of a benthic adult stage, with lateral blastopore closure creating a tube-shaped gut. The archaeotroch became differentiated as prototroch, metatroch and telotroch in the (trochophora) larva, but was lost in the adult. The apical ganglion was lost in the adult, as in all neuralians. Paired cerebral ganglia developed from the first micromere quartet. The circumblastoporal nerve became differentiated into a pair of ventral nerve cords with loops around mouth (the anterior part of the blastopore) and anus. Almost all new information about morphology and embryology fits the trochaea theory. The predicted presence of a perioral loop of the blastoporal nerve ring has now been demonstrated in two annelids. Alternative ‘intercalation theories’ propose that planktotrophic larvae evolved many times from direct-developing ancestors, but this finds no support from considerations of adaptation.

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Adaptation of retinal ganglion cell function during flickering light in the mouse

Scientific Reports ◽

10.1038/s41598-019-54930-4 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 3

Author(s):

Tsung-Han Chou ◽

Jonathon Toft-Nielsen ◽

Vittorio Porciatti

Keyword(s):

Ganglion Cell ◽

Retinal Ganglion Cell ◽

Cell Function ◽

Temporal Dynamics ◽

Pattern Electroretinogram ◽

Mouse Strains ◽

Retinal Ganglion ◽

Response Dynamics ◽

Flickering Light ◽

Induced Changes

AbstractRapid dilation of retinal vessels in response to flickering light (functional hyperemia) is a well-known autoregulatory response driven by increased neural activity in the inner retina. Little is known about flicker-induced changes of activity of retinal neurons themselves. We non-invasively investigated flicker-induced changes of retinal ganglion cell (RGC) function in common inbred mouse strains using the pattern electroretinogram (PERG), a sensitive measure of RGC function. Flicker was superimposed on the pattern stimulus at frequencies that did not generate measurable flicker-ERG and alter the PERG response. Transition from flicker at 101 Hz (control) to flicker at 11 Hz (test) at constant mean luminance induced a slow reduction of PERG amplitude to a minimum (39% loss in C57BL/6J mice and 52% loss in DBA/2J mice) 4–5 minutes after 11 Hz flicker onset, followed by a slow recovery to baseline over 20 minutes. Results demonstrate that the magnitude and temporal dynamics of RGC response induced by flicker at 11 Hz can be non-invasively assessed with PERG in the mouse. This allows investigating the functional phenotype of different mouse strains as well as pathological changes in glaucoma and optic nerve disease. The non-contact flicker-PERG method opens the possibility of combined assessment of neural and vascular response dynamics.

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Regional tongue deformations during chewing and drinking in the pig

Integrative Organismal Biology ◽

10.1093/iob/obab012 ◽

2021 ◽

Author(s):

Rachel A Olson ◽

Stéphane J Montuelle ◽

Hannah Curtis ◽

Susan H Williams

Keyword(s):

Soft Tissues ◽

Temporal Dynamics ◽

Regional Level ◽

Functional Variation ◽

Jaw Movements ◽

Global Properties ◽

Functional Differences ◽

Multiple Regions ◽

Future Work ◽

Shape Changes

Abstract As a muscular hydrostat, the tongue undergoes complex deformations during most oral behaviors, including chewing and drinking. During these behaviors, deformations occur in concert with tongue and jaw movements to position and transport the bolus. Moreover, the various parts of the tongue may move and deform at similar timepoints relative to the gape cycle or they may occur at different timepoints, indicating regional biomechanical and functional variation. The goal of this study is to quantify tongue biomechanics during chewing and drinking in pigs by characterizing intrinsic deformations of the tongue across multiple regions simultaneously. Tongue deformations are generally larger during chewing cycles compared to drinking cycles. Chewing and drinking also differ in the timing of regional length and width, but not total length, deformations. This demonstrates functional differences in the temporal dynamics of localized shape changes whereas the global properties of jaw-tongue coordination are maintained. Finally, differences in the trade-off between length and width deformations demonstrate that the properties of a muscular hydrostat are observed at the whole tongue level, but biomechanical variation (e.g., changes in movements and deformations) at the regional level exists. This study provides new critical insights into the regional contributions to tongue deformations as a basis for future work on multidimensional shape changes in soft tissues.

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Temporal Tuning of Word- and Face-selective Cortex

Journal of Cognitive Neuroscience ◽

10.1162/jocn_a_01002 ◽

2016 ◽

Vol 28 (11) ◽

pp. 1820-1827 ◽

Cited By ~ 9

Author(s):

Jason D. Yeatman ◽

Anthony M. Norcia

Keyword(s):

Steady State ◽

Temporal Resolution ◽

Temporal Dynamics ◽

Temporal Frequency ◽

Object Processing ◽

Fundamental Parameters ◽

Face Images ◽

The Face ◽

Full Screen ◽

Differential Tuning

Sensitivity to temporal change places fundamental limits on object processing in the visual system. An emerging consensus from the behavioral and neuroimaging literature suggests that temporal resolution differs substantially for stimuli of different complexity and for brain areas at different levels of the cortical hierarchy. Here, we used steady-state visually evoked potentials to directly measure three fundamental parameters that characterize the underlying neural response to text and face images: temporal resolution, peak temporal frequency, and response latency. We presented full-screen images of text or a human face, alternated with a scrambled image, at temporal frequencies between 1 and 12 Hz. These images elicited a robust response at the first harmonic that showed differential tuning, scalp topography, and delay for the text and face images. Face-selective responses were maximal at 4 Hz, but text-selective responses, by contrast, were maximal at 1 Hz. The topography of the text image response was strongly left-lateralized at higher stimulation rates, whereas the response to the face image was slightly right-lateralized but nearly bilateral at all frequencies. Both text and face images elicited steady-state activity at more than one apparent latency; we observed early (141–160 msec) and late (>250 msec) text- and face-selective responses. These differences in temporal tuning profiles are likely to reflect differences in the nature of the computations performed by word- and face-selective cortex. Despite the close proximity of word- and face-selective regions on the cortical surface, our measurements demonstrate substantial differences in the temporal dynamics of word- versus face-selective responses.

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Alterations in the number of motoneurons containing immunoreactive calcitonin gene-related peptide(CGRP)& choline acetyltransferase(ChAT) in the cervical spinal cord of the wobbler mouse during the development of the motoneuron disease

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100141226 ◽

1995 ◽

Vol 53 ◽

pp. 970-971

Author(s):

L. Vacca-Galloway ◽

Y.Q. Zhang ◽

P. Bose ◽

S.H. Zhang

Keyword(s):

Spinal Cord ◽

Early Stage ◽

Cervical Spinal Cord ◽

Wild Type Mouse ◽

Reflex Response ◽

Mouse Strains ◽

Behavioral Tests ◽

Wobbler Mouse ◽

Stage 4 ◽

Stage 1

The Wobbler mouse (wr) has been studied as a model for inherited human motoneuron diseases (MNDs). Using behavioral tests for forelimb power, walking, climbing, and the “clasp-like reflex” response, the progress of the MND can be categorized into early (Stage 1, age 21 days) and late (Stage 4, age 3 months) stages. Age-and sex-matched normal phenotype littermates (NFR/wr) were used as controls (Stage 0), as well as mice from two related wild-type mouse strains: NFR/N and a C57BI/6N. Using behavioral tests, we also detected pre-symptomatic Wobblers at postnatal ages 7 and 14 days. The mice were anesthetized and perfusion-fixed for immunocytochemical (ICC) of CGRP and ChAT in the spinal cord (C3 to C5).Using computerized morphomety (Vidas, Zeiss), the numbers of IR-CGRP labelled motoneurons were significantly lower in 14 day old Wobbler specimens compared with the controls (Fig. 1). The same trend was observed at 21 days (Stage 1) and 3 months (Stage 4). The IR-CGRP-containing motoneurons in the Wobbler specimens declined progressively with age.

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An ultrastructural analysis of the sympathetic innervation of the rabbit ear artery and middle cerebral artery and their branches

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100125075 ◽

1992 ◽

Vol 50 (1) ◽

pp. 934-935

Author(s):

John T. Dodge ◽

John A. Bevan

Keyword(s):

Middle Cerebral Artery ◽

Cerebral Artery ◽

Sympathetic Innervation ◽

Electrical Field Stimulation ◽

Rabbit Ear Artery ◽

Electrical Field ◽

Functional Differences ◽

Ear Artery ◽

Rabbit Ear ◽

Vascular Beds

Unlike many peripheral vascular beds, the sympathetic nervous system exerts little control on cerebral blood flow. The contractile response of isolated rabbit middle cerebral artery (MCA) segments to electrical field stimulation of its intramural nerves is less than in a similar-sized artery from the ear. This study was undertaken to characterize and compare the perivascular neuromuscular relationships and innervation density of similar-sized arteries varying in diameter from these two different regional arterial beds to see if there were structural correlates for these functional differences.

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Fine structure of the rectal papillae of the oriental fruuit fly, Dacus dorsalis Hendel (Tephritidae, Diptera Insecta)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100160042 ◽

1990 ◽

Vol 48 (3) ◽

pp. 498-499

Author(s):

Len Wen-Yung ◽

Mei-Jung Lin

Keyword(s):

Fine Structure ◽

Cell Membrane ◽

Intercellular Space ◽

Anterior Part ◽

Apical Cell ◽

Posterior Part ◽

Apical Cell Membrane ◽

Dacus Dorsalis ◽

Radial Cell ◽

Circular Base

Four cone-shaped rectal papillae locate at the anterior part of the rectum in Dacus dorsalis fly. The circular base of the papilla protrudes into the haemolymph (Fig. 1,2) and the rest cone-shaped tip (Fig. 2) inserts in the rectal lumen. The base is surrounded with the cuticle (Fig. 5). The internal structure of the rectal papilla (Fig. 3) comprises of the cortex with the columnar epithelial cells and a rod-shaped medulla. Between them, there is the infundibular space and many trabeculae connect each other. Several tracheae insert into the papilla through the top of the medulla, then run into the cortical epithelium and locate in the intercellular space. The intercellular sinuses distribute in the posterior part of the rectal papilla.The cortex of the base divides into about thirty segments. Between segments there is a radial cell (Fig. 4). Under the cuticle, the apical cell membrane of the cortical epithelium is folded into a regular border of leaflets (Fig. 5).

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