scholarly journals Whole body regeneration and developmental competition in two botryllid ascidians

EvoDevo ◽  
2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Shane Nourizadeh ◽  
Susannah Kassmer ◽  
Delany Rodriguez ◽  
Laurel S. Hiebert ◽  
Anthony W. De Tomaso
Keyword(s):  
Resource Allocation ◽  
Asexual Reproduction ◽  
Marine Invertebrate ◽  
Whole Body ◽  
Minimal Amount ◽  
Botryllus Schlosseri ◽  
Common Theme ◽  
New Model ◽  
Competitive Mechanism ◽  
Botrylloides Diegensis

Abstract Background Botryllid ascidians are a group of marine invertebrate chordates that are colonial and grow by repeated rounds of asexual reproduction to form a colony of individual bodies, called zooids, linked by a common vascular network. Two distinct processes are responsible for zooid regeneration. In the first, called blastogenesis, new zooids arise from a region of multipotent epithelium from a pre-existing zooid. In the second, called whole body regeneration (WBR), mobile cells in the vasculature coalesce and are the source of the new zooid. In some botryllid species, blastogenesis and WBR occur concurrently, while in others, blastogenesis is used exclusively for growth, while WBR only occurs following injury or exiting periods of dormancy. In species such as Botrylloides diegensis, injury induced WBR is triggered by the surgical isolation of a small piece of vasculature. However, Botryllus schlosseri has unique requirements that must be met for successful injury induced WBR. Our goal was to understand why there would be different requirements between these two species. Results While WBR in B. diegensis was robust, we found that in B. schlosseri, new zooid growth following injury is unlikely due to circulatory cells, but instead a result of ectopic development of tissues leftover from the blastogenic process. These tissues could be whole, damaged, or partially resorbed developing zooids, and we defined the minimal amount of vascular biomass to support ectopic regeneration. We did find a common theme between the two species: a competitive process exists which results in only a single zooid reaching maturity following injury. We utilized this phenomenon and found that competition is reversible and mediated by circulating factors and/or cells. Conclusions We propose that WBR does not occur in B. schlosseri and that the unique requirements defined in other studies only serve to increase the chances of ectopic development. This is likely a response to injury as we have discovered a vascular-based reversible competitive mechanism which ensures that only a single zooid completes development. This competition has been described in other species, but the unique response of B. schlosseri to injury provides a new model to study resource allocation and competition within an individual.

scholarly journals In-land long-term culture of colonial ascidians

2021 ◽  
Author(s):  
M. Wawrzyniak ◽  
L.A. Matas Serrato ◽  
S. Blanchoud
Keyword(s):  
Vascular System ◽  
Marine Invertebrate ◽  
Natural Habitat ◽  
Automated System ◽  
Whole Body ◽  
List Type ◽  
Feeding Rates ◽  
Botrylloides Diegensis ◽  
Colonial Ascidians

1.AbstractTunicates are highly diverse marine invertebrate filter-feeders that are vertebrates’ closest relatives. These organisms, despite a drastically different body plan during their adulthood, have a tissue complexity related to that of vertebrates. Ascidians, which compose most of the Tunicata, are benthic sessile hermaphrodites that reproduce sexually through a motile tadpole larval stage. Over half of the known ascidians species are able to reproduce asexually through budding, typically leading to the formation of colonies where animals, called zooids, are interconnected by an external vascular system. In addition, colonial ascidians are established models for important biological processes including allorecognition, immunobiology, aging, angiogenesis and whole-body regeneration. However, the current paucity in breeding infrastructures limits the study of these animals to coastal regions.To promote a wider scientific spreading and popularity of colonial ascidians, we have developed a flexible recirculating husbandry setup for their long-term in-lab culture. Our system is inspired both by the flow-through aquariums used by coastal ascidian labs, as well as by the recirculating in-lab systems used for zebrafish research. Our hybrid system thus combines colony breeding, water filtering and food culturing in a semi-automated system where specimens develop on hanging microscopy glass slides. Temperature, light/dark cycles, flow speed and feeding rates can be controlled independently in four different breeding environments to provide room for species-specific optimization as well as for running experiments. This setup is complemented with a quarantine for the acclimatization of wild isolates.We here present our success in breeding Botrylloides diegensis, a species of colonial ascidians, for more than 3 years in recirculating artificial seawater over 600 km from their natural habitat. We show that colonies adapt well to in-lab culturing and that a specific strain can be isolated, propagated and used for research efficiently over prolonged periods of time. The flexible and modular structure of our system can be scaled and adapted to the needs of specific species as well as of particular laboratory spaces. Overall, we show that Botrylloides diegensis can be proficiently bred in-land and suggest that our results can be extended to other species of colonial ascidians to promote research on these fascinating animals.HighlightsFirst in-land recirculating aquaculture for colonial ascidiansOver 3 years of continuous breedingSemi-automated setup with minimized maintenanceGood biomass production for strain propagation4 different culture conditions for optimized breeding for species of interest

ARO: A new model free optimization algorithm for real time applications inspired by the asexual reproduction

2011 ◽  
Vol 38 (5) ◽  
pp. 4866-4874 ◽  
Author(s):  
Taha Mansouri ◽  
Alireza Farasat ◽  
Mohammad B. Menhaj ◽  
Mohammad Reza Sadeghi Moghadam
Keyword(s):  
Real Time ◽  
Asexual Reproduction ◽  
Optimization Algorithm ◽  
New Model ◽  
Model Free ◽  
Real Time Applications

Botryllus schlosseri: A model ascidian for the study of asexual reproduction

2007 ◽  
Vol 236 (2) ◽  
pp. 335-352 ◽  
Author(s):  
L. Manni ◽  
G. Zaniolo ◽  
F. Cima ◽  
P. Burighel ◽  
L. Ballarin
Keyword(s):  
Asexual Reproduction ◽  
Botryllus Schlosseri

scholarly journals A novel transplantable model of lung cancer associated tissue loss and disrupted muscle regeneration

2019 ◽  
Author(s):  
Paige C Arneson ◽  
Alexandra M Ducharme ◽  
Jason D Doles
Keyword(s):  
Lung Cancer ◽  
Muscle Regeneration ◽  
Muscle Wasting ◽  
Cell Number ◽  
Tissue Loss ◽  
Whole Body ◽  
Complete Analysis ◽  
Survival Times ◽  
New Model ◽  
Progressive Loss

ABSTRACTBackgroundCancer-associated muscle wasting (CAW), a symptom of cancer cachexia, is associated with approximately 20% of lung cancer deaths, and remains poorly characterized on a mechanistic level. Current animal models for lung cancer-associated cachexia are limited in that they: 1) primarily employ flank transplantation methods, 2) have short survival times not reflective of the patient condition, and 3) are typically performed in young mice not representative of mean patient age. This study investigates a new model for lung cancer-associated cachexia that can address these issues and also implicates muscle regeneration as a contributor to CAW.MethodsWe used tail vein injection as a method to introduce tumor cells that seed primarily in the lungs of mice. Body composition of tumor bearing mice was longitudinally tracked using NMR-based, echo magnetic resonance imaging (echoMRI). These data were combined with histological and molecular assessments of skeletal muscle to provide a complete analysis of muscle wasting.ResultsIn this new lung CAW model we observed 1) progressive loss in whole body weight, 2) progressive loss of lean and fat mass, 3) a circulating cytokine/inflammatory profile similar to that seen in other models of CAW, 4) histological changes associated with muscle wasting, and 5) molecular changes in muscle that implicate suppression of muscle repair/regeneration. Finally, we show that survival can be extended without lessening CAW by titrating injected cell number.ConclusionsOverall, this study describes a new model of CAW that could be useful for further studies of lung cancer-associated wasting and accompanying changes in the regenerative capacity of muscle. Additionally, this model addresses many recent concerns with existing models such as immunocompetence, tumor location, and survival time.

scholarly journals 15-Minute City: Decomposing the New Urban Planning Eutopia

2021 ◽  
Vol 13 (2) ◽  
pp. 928
Author(s):  
Georgia Pozoukidou ◽  
Zoi Chatziyiannaki
Keyword(s):  
Resource Allocation ◽  
Urban Planning ◽  
Functional Element ◽  
Optimal Resource Allocation ◽  
New Model ◽  
Safety And Health ◽  
Optimal Resource ◽  
Allocation Patterns ◽  
Second Wave ◽  
Urban Functions

As cities are struggling to cope with the second wave of the global COVID-19 pandemic, the idea of 15-min cities seem to have sparked planners’ imagination and politicians’ willingness for providing us with a new urban planning eutopia. This paper explores the “15-min city” concept as a structural and functional element for redesigning contemporary cities. Methodologically, a study of three case cities that have adopted this new model of city vision, is carried out. The analysis focus on understanding how the idea of 15-min cities fits the legacies of different cities as described by traditional planning principles in the context of three evaluation pillars: inclusion, safety and health. The paper argues that the 15-min city approach is not a radical new idea since it utilizes long established planning principles. Nevertheless, it uses these principles to achieve the bottom-up promotion of wellbeing while it proposes an alternative way to think about optimal resource allocation in a citywide scale. Hence, application of 15-min city implies a shift in the emphasis of planning from the accessibility of neighborhood to urban functions to the proximity of urban functions within neighborhoods, along with large systemic changes in resource allocation patterns and governance schemes citywide.

Resource Allocation to Asexual Gemma Production and Sexual Reproduction in South-Western Australian Pygmy and Micro Stilt-Form Species of Sundew (Drosera spp, Droseraceae)

1992 ◽  
Vol 40 (3) ◽  
pp. 353 ◽  
Author(s):  
PS Karlsson ◽  
JS Pate
Keyword(s):  
Resource Allocation ◽  
Sexual Reproduction ◽  
Seed Production ◽  
Asexual Reproduction ◽  
Western Australia ◽  
Dry Matter ◽  
Late Season ◽  
Plant Resource ◽  
Total Plant ◽  
Western Australian

Proportional allocations of current total dry matter (DM), N and P to early season asexual gemma production and late-season flowering and seed production were compared for eight pygmy rosette form and three micro stilt-form perennial pygmy sundews (Drosera spp.) in native habitat in south-western Australia. Mean allocations to gemmae for the smaller rosette species were 22% for DM, 60% for N and 38% for P versus 8, 20 and 23% (DM, N, P) respectively for the micro stilt forms. Allocations to mature fully formed seeds were extremely low, 1-8, 4.0 and 5.4% (DM, N, P) for the rosette forms, 0.7, 3-0 and 2.3% respectively for the micro stilt forms. The above values reflect the heavy bias towards gemma production, (8-52 propagules per plant per season across the 11 species) as opposed to that for seed (0-8 fully formed seeds per plant per season). Comparable information for the annual nongemmiferous pygmy sundew D. glanduligera showed end of season allocation of 66, 37 and 29% (DM, N, P) of total plant resource to inflorescences minus seeds, and additional amounts equivalent to 30, 59 and 69% to the 60 seeds produced per plant of this species in the study season. A detailed phenology of resource allocation across a full season of growth in second, third and fourth season plants of the rosette perennial D. closterostigma showed net seasonal losses in the total vegetative resource of N and of P in older plants attributable to apparent over commitment to asexual reproduction during the season of study.

Measurement of pyruvate and lactate kinetics across the hindlimb and gut of anesthetized dogs

1994 ◽  
Vol 267 (1) ◽  
pp. E174-E182 ◽  
Author(s):  
D. L. Chinkes ◽  
X. J. Zhang ◽  
J. A. Romijn ◽  
Y. Sakurai ◽  
R. R. Wolfe
Keyword(s):  
Free Water ◽  
Whole Body ◽  
Transmembrane Transport ◽  
New Model ◽  
Lactate Kinetics ◽  
Stable Isotopic ◽  
Anesthetized Dogs ◽  
Flow Through ◽  
Lactate And Pyruvate

We have developed a new model to quantify regional pyruvate and lactate transmembrane transport, shunting, exchange, production, and oxidation in vivo. The method is based on the systemic continuous infusion of pyruvate or lactate stable isotopic carbon tracers and the measurement of pyruvate and lactate enrichment and concentration in the artery and vein of that region (e.g., leg or gut), the pyruvate and lactate enrichment of intracellular free water in the tissue as measured by biopsy, and the rate of blood flow through the tissue. The purpose of the experiment was to measure the pyruvate and lactate kinetics in leg muscle and gut in anesthetized dogs (n = 6). The transmembrane transport and degree of shunting of pyruvate and lactate were comparable in muscle and gut. When modified for substrate inflow, interconversion between pyruvate and lactate took place at a rate twice as fast in muscle as in the gut, and production and oxidation of pyruvate was approximately 50% greater in muscle than in the gut. Thus our new model enables quantitation of many aspects of lactate and pyruvate kinetics. We conclude that in anesthetized animals the muscle is the tissue most responsible for whole body peripheral pyruvate and lactate kinetics.

scholarly journals Almost Envy-Freeness in Group Resource Allocation

2019 ◽  
Author(s):  
Maria Kyropoulou ◽  
Warut Suksompong ◽  
Alexandros A. Voudouris
Keyword(s):  
Resource Allocation ◽  
Fair Allocation ◽  
Indivisible Goods ◽  
New Model

We study the problem of fairly allocating indivisible goods between groups of agents using the recently introduced relaxations of envy-freeness. We consider the existence of fair allocations under different assumptions on the valuations of the agents. In particular, our results cover cases of arbitrary monotonic, responsive, and additive valuations, while for the case of binary valuations we fully characterize the cardinalities of two groups of agents for which a fair allocation can be guaranteed with respect to both envy-freeness up to one good (EF1) and envy-freeness up to any good (EFX). Moreover, we introduce a new model where the agents are not partitioned into groups in advance, but instead the partition can be chosen in conjunction with the allocation of the goods. In this model, we show that for agents with arbitrary monotonic valuations, there is always a partition of the agents into two groups of any given sizes along with an EF1 allocation of the goods. We also provide an extension of this result to any number of groups.

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