scholarly journals Evolution of ovipositor length in Drosophila suzukii is driven by enhanced cell size expansion and anisotropic tissue reorganization

2018 ◽  
Author(s):  
Jack E. Green ◽  
Matthieu Cavey ◽  
Emmanuelle Caturegli ◽  
Nicolas Gompel ◽  
Benjamin Prud’homme
Keyword(s):  
Cell Size ◽  
Time Window ◽  
Egg Laying ◽  
Fine Tuning ◽  
Size Difference ◽  
Size And Shape ◽  
Ovipositor Length ◽  
Cell Shapes ◽  
Isotropic Expansion ◽  
Apical Area

AbstractMorphological diversity is dominated by variation in body proportion. Yet the cellular processes underlying differential growth of morphological traits between species remain largely unknown. Here we compare the ovipositors of two closely related species, Drosophila melanogaster and D. suzukii. D. suzukii has switched its egg-laying niche from rotting to ripe fruit. Along with this shift, the D. suzukii ovipositor has undergone a significant change in size and shape. Using an allometric approach we find that, while adult ovipositor width has hardly changed between the species, D. suzukii ovipositor length is almost double that of D. melanogaster. We show that this size difference mostly arises during a 6-hour time window in the middle of pupal development. We observe that the developing ovipositors of the two species comprise an almost identical number of cells, with a very similar profile of cell shapes and orientations. After cell division stops, we find that the ovipositor area continues to grow through the isotropic expansion of cell apical area. Remarkably, at one point, the rate of cell apical area expansion is more than 4 times faster in D. suzukii than in D. melanogaster. In addition, we find that an anisotropic cellular reorganization of the developing ovipositor results in a net elongation of the tissue, despite the isotropic expansion of cell size, and is enhanced in D. suzukii. Therefore, the quantitative fine-tuning of shared, morphogenetic processes -the rate of cell size expansion and the cellular rearrangements–can drive macroscopic evolutionary changes in organ size and shape.

scholarly journals Sexual differences in size and shape of the Mosor rock lizard [Dinarolacerta mosorensis (Kolombatovic, 1886)] (squamata: lacertidae): A case study of the Lovcen mountain population (Montenegro)

2008 ◽  
Vol 60 (2) ◽  
pp. 279-288 ◽  
Author(s):  
Katarina Ljubisavljevic ◽  
Lidija Polovic ◽  
Ana Ivanovic
Keyword(s):  
Sexual Differences ◽  
Size Difference ◽  
Morphometric Characters ◽  
Positive Allometry ◽  
Size And Shape ◽  
Rock Lizard ◽  
Head Height ◽  
Dorsal Pattern ◽  
Mountain Population

Sexual differences in size and shape of the Mosor rock lizard, Dinarolacerta mosorensis (Kolombatovic, 1886), from Lovcen Mountain (Montenegro) were examined on the basis of the intersex variation pattern of nine morphometric, eight pholidotic, and four qualitative traits. Sexual dimorphism was apparent for all morphometric characters except snout-vent length, while scalation and dorsal pattern exhibited small differences between sexes. The value of the sexual size difference (SSD) index based on snout-vent length was 1.028. The sex-specific allometric slopes for head dimensions and interlimb distance significantly diverged. Head dimensions, especially head height, showed strong positive allometry in males, while interlimb distance was the only character which showed positive allometry in females. Generally, males had significantly greater body size than females. This was true of all body measurements except interlimb distance. The influence of sexual and natural selection on the examined traits is discussed.

scholarly journals Time of Your Hate: The Challenge of Time in Hate Speech Detection on Social Media

2020 ◽  
Vol 10 (12) ◽  
pp. 4180 ◽  
Author(s):  
Komal Florio ◽  
Valerio Basile ◽  
Marco Polignano ◽  
Pierpaolo Basile ◽  
Viviana Patti
Keyword(s):  
Social Media ◽  
Hate Speech ◽  
Time Window ◽  
Classification Performance ◽  
Fine Tuning ◽  
Classification Model ◽  
Temporal Distance ◽  
Speech Detection ◽  
Highly Sensitive

The availability of large annotated corpora from social media and the development of powerful classification approaches have contributed in an unprecedented way to tackle the challenge of monitoring users’ opinions and sentiments in online social platforms across time. Such linguistic data are strongly affected by events and topic discourse, and this aspect is crucial when detecting phenomena such as hate speech, especially from a diachronic perspective. We address this challenge by focusing on a real case study: the “Contro l’odio” platform for monitoring hate speech against immigrants in the Italian Twittersphere. We explored the temporal robustness of a BERT model for Italian (AlBERTo), the current benchmark on non-diachronic detection settings. We tested different training strategies to evaluate how the classification performance is affected by adding more data temporally distant from the test set and hence potentially different in terms of topic and language use. Our analysis points out the limits that a supervised classification model encounters on data that are heavily influenced by events. Our results show how AlBERTo is highly sensitive to the temporal distance of the fine-tuning set. However, with an adequate time window, the performance increases, while requiring less annotated data than a traditional classifier.

scholarly journals A rapid method of fruit cell isolation for cell size and shape measurements

Plant Methods ◽  
2009 ◽  
Vol 5 (1) ◽  
pp. 5 ◽  
Author(s):  
Peter A McAtee ◽  
Ian C Hallett ◽  
Jason W Johnston ◽  
Robert J Schaffer
Keyword(s):  
Cell Size ◽  
Rapid Method ◽  
Cell Isolation ◽  
Size And Shape

Strombidiid ciliates from coastal waters near Kingston Harbour, Jamaica (Ciliophora, Oligotrichia, Strombidiidae)

1993 ◽  
Vol 73 (1) ◽  
pp. 47-65 ◽  
Author(s):  
Denis H. Lynn ◽  
Guy L. Gilron
Keyword(s):  
New Species ◽  
Cell Size ◽  
Coastal Waters ◽  
Caribbean Sea ◽  
Size And Shape ◽  
The Caribbean ◽  
Kingston Harbour ◽  
One New Species

Fifteen marine strombidiid species were measured and identified after protargol staining of bottle-cast samples collected during an annual study of the ciliate microzooplankton in the Caribbean Sea. Nine of these are described herein as new species. One new species from the genus Tontonia, T. simplicidens sp. nov., is defined, based on the pattern of the girdle and ventral kinety. Six new species of Strombidium, S. bilobum sp. nov., S. eurystomum sp. nov., S. ioanum sp. nov., S. maedai sp. nov., S. pollostomum sp. nov. and S. sphaericum sp. nov. are defined, based on cell size and shape, the arrangement of the oral ciliature, and the nature of the macronucleus. One new strombidiid genus Cyrtostrombidium gen. nov., is defined by the presence of a unique oral ‘basket’ and the absence of the ventral polykinetidal zone. Two species of Cyrtostrombidium, C. longisomum sp. nov. and C. wailesi sp. nov., are distinguished, based on cell size and macronuclear structure. Assemblages of six previously-described strombidiid species, S. constrictum, S. dalum, S. epidemum, S. inclinatum, S. wulffi, and Laboea strobila are also briefly described.

Diffusing capacity reexamined: relative roles of diffusion and chemical reaction in red cell uptake of O2, CO, CO2, and NO

2004 ◽  
Vol 97 (6) ◽  
pp. 2284-2302 ◽  
Author(s):  
Saikat Chakraborty ◽  
Vemuri Balakotaiah ◽  
Akhil Bidani
Keyword(s):  
Plasma Layer ◽  
Cell Uptake ◽  
Diffusion Reaction ◽  
Theoretical Expression ◽  
Diffusing Capacity ◽  
Transfer Resistance ◽  
Size And Shape ◽  
Cell Shapes ◽  
Reactive Gases

This paper presents an analytical expression for the diffusing capacity (Θ t) of the red blood cell (RBC) for any reactive gas in terms of size and shape of the RBC, thickness of the unstirred plasma layer surrounding the RBC, diffusivities and solubilities of the gas in RBC and boundary layer, hematocrit, and the slope of the dissociation curve. The expression for Θ t has been derived by spatial averaging of the fundamental convection-diffusion-reaction equation for O2 in the RBC and has been generalized to all cell shapes and for other reactive gases such as CO, NO, and CO2. The effects of size and shape of the RBC, thickness of the unstirred plasma layer, hemoglobin concentration, and hematocrit on Θ t have been analyzed, and the analytically obtained expression for Θ t has been validated by comparison with different sets of existing experimental data for O2 and CO2. Our results indicate that the discoidal shape of the human RBC with average dimensions of 1.6-μm thickness and 8-μm diameter is close to optimal design for O2 uptake and that the true reaction velocity in the RBC is suppressed significantly by the mass transfer resistance in the surrounding unstirred layer. In vitro measurements using rapid-mixing technique, which measures Θ t in the presence of artificially created large boundary layers, substantially underpredicts the in vivo diffusing capacity of the RBC in the diffusion-controlled regime. Depending on the conditions in the RBC, uptake of less reactive gases (such as CO) undergoes transition from reaction-limited to diffusion-limited regime. For a constant set of morphological parameters, the theoretical expression for Θ t predicts that Θ t,NO > Θ t,CO2 > Θ t,O2 > Θ t,CO.

scholarly journals Potential for Control of Signaling Pathways via Cell Size and Shape

2006 ◽  
Vol 16 (17) ◽  
pp. 1685-1693 ◽  
Author(s):  
Jason Meyers ◽  
Jennifer Craig ◽  
David J. Odde
Keyword(s):  
Signaling Pathways ◽  
Cell Size ◽  
Size And Shape

scholarly journals Rate of cell cycle initiation of yeast cells when cell size is not a rate-determining factor

1983 ◽  
Vol 59 (1) ◽  
pp. 183-201 ◽  
Author(s):  
P.G. Lord ◽  
A.E. Wheals
Keyword(s):  
Cell Cycle ◽  
Steady State ◽  
Cell Size ◽  
Cycle Time ◽  
Yeast Cells ◽  
Size Difference ◽  
Birth Size ◽  
Daughter Cells ◽  
Alpha Factor ◽  
Determining Factor

The control of cell proliferation under steady-state conditions in the budding yeast, Saccharomyces cerevisiae, is well described by either the tandem or sloppy size control models, both of which suggest that differences in cycle time between individual cells or between parents and daughters is largely due to differences in birth size. These models have been investigated further under conditions in which cell size has not been a rate-determining factor for cell cycle initiation. Two approaches have been used. The first involves the growth of cells in low concentrations of hydroxyurea (HU), which has the effect of prolonging the duration of DNA synthesis. This leads to a lengthening of the budded period, which in turn leads to daughter cells being larger at division than the normal cell cycle initiation size of daughters in steady-state populations. The second approach involves the accumulation of cells at the key control point of the cycle, called start, using the pheromone alpha-factor. Since growth is unaffected, all cells eventually become larger than the volume at which they would normally initiate the cell cycle. The kinetics of proliferation were followed after release from alpha-factor arrest. The results from both approaches were broadly consistent with the predictions of both models. However, abolition of birth-size differences between parents and daughters in the presence of HU did not lead to a complete disappearance of differences in either cycle time or proliferation kinetics. Furthermore, following release from alpha-factor arrest, the rate of cell cycle initiation of parent cells was slower than in steady-state culture and the daughters' cells behaved as if comprising two separate populations. These discrepancies suggest that besides a size difference, there are additional physiological differences between parent and daughter cells.

scholarly journals The ghosts of parasitism past: lingering frontline anti-brood parasite defences in a former host

2021 ◽  
Author(s):  
Matthew H J Chaumont ◽  
Naomi E Langmore ◽  
Justin A Welbergen
Keyword(s):  
Brood Parasitism ◽  
Species Interactions ◽  
Egg Laying ◽  
Arms Race ◽  
Fine Tuning ◽  
Brood Parasite ◽  
Reed Warbler ◽  
Arms Races ◽  
Brood Parasites ◽  
Defensive Behaviors

Abstract Coevolutionary arms races between brood parasites and hosts provide tractable systems for understanding antagonistic coevolution in nature; however, little is known about the fate of frontline antiparasite defences when the host ‘wins’ the coevolutionary arms race. By recreating bygone species-interactions, using artificial parasitism experiments, lingering defensive behaviors that evolved in the context of parasitism can be understood and may even be used to identify the unknown agent of parasitism past. Here we present the first study of this type by evaluating lingering “frontline” nest defences that have evolved to prevent egg laying in a former brood parasite host. The Australian reed warbler Acrocephalus australis, is currently not parasitized but is known to exhibit fine-tuned egg discrimination—a defensive behavior indicative of a past brood parasite-host arms race and common in closely related parasitized species. Here, using 3 D-printed models of adult brood parasites, we examined whether the Australian reed warbler also exhibits frontline defences to adult brood parasites, and whether we could use these defences to identify the warbler’s “ghost of parasitism past”. Our findings provide evidence that the Australian reed warbler readily engages in frontline defences that are considered adaptive specifically in the context of brood parasitism. However, individuals were unable to discriminate between adults of different brood parasite species at their nest. Overall, our results demonstrate that despite a relaxation in selection, defences against brood parasitism can be maintained across multiple stages of the host’s nesting cycle, and further suggest that, in accordance with previous findings, that learning may be important for fine-tuning frontline defence.

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