scholarly journals Dynamic mechanical oscillations during metamorphosis of the monarch butterfly

2008 ◽  
Vol 6 (30) ◽  
pp. 29-37 ◽  
Author(s):  
Andrew E Pelling ◽  
Paul R Wilkinson ◽  
Richard Stringer ◽  
James K Gimzewski
Keyword(s):  
Structural Changes ◽  
Morphological Changes ◽  
Danaus Plexippus ◽  
Monarch Butterfly ◽  
Mechanical Quality Factor ◽  
Beam Deflection ◽  
Mechanical Oscillation ◽  
Insect Metamorphosis ◽  
Magnetic Resonance Imaging Mri

The mechanical oscillation of the heart is fundamental during insect metamorphosis, but it is unclear how morphological changes affect its mechanical dynamics. Here, the micromechanical heartbeat with the monarch chrysalis ( Danaus plexippus ) during metamorphosis is compared with the structural changes observed through in vivo magnetic resonance imaging (MRI). We employ a novel ultra-sensitive detection approach, optical beam deflection, in order to measure the microscale motions of the pupae during the course of metamorphosis. We observed very distinct mechanical contractions occurring at regular intervals, which we ascribe to the mechanical function of the heart organ. Motion was observed to occur in approximately 15 min bursts of activity with frequencies in the 0.4–1.0 Hz range separated by periods of quiescence during the first 83 per cent of development. In the final stages, the beating was found to be uninterrupted until the adult monarch butterfly emerged. Distinct stages of development were characterized by changes in frequency, amplitude, mechanical quality factor and de/repolarization times of the mechanical pulsing. The MRI revealed that the heart organ remains functionally intact throughout metamorphosis but undergoes morphological changes that are reflected in the mechanical oscillation.

scholarly journals Cardenolides, toxicity, and the costs of sequestration in the coevolutionary interaction between monarchs and milkweeds

2021 ◽  
Vol 118 (16) ◽  
pp. e2024463118
Author(s):  
Anurag A. Agrawal ◽  
Katalin Böröczky ◽  
Meena Haribal ◽  
Amy P. Hastings ◽  
Ronald A. White ◽  
...  
Keyword(s):  
Danaus Plexippus ◽  
Monarch Butterfly ◽  
Chemical Defenses ◽  
Trade Off ◽  
Asclepias Curassavica ◽  
Plant Chemical ◽  
Whole Plants ◽  
Benefits And Costs

For highly specialized insect herbivores, plant chemical defenses are often co-opted as cues for oviposition and sequestration. In such interactions, can plants evolve novel defenses, pushing herbivores to trade off benefits of specialization with costs of coping with toxins? We tested how variation in milkweed toxins (cardenolides) impacted monarch butterfly (Danaus plexippus) growth, sequestration, and oviposition when consuming tropical milkweed (Asclepias curassavica), one of two critical host plants worldwide. The most abundant leaf toxin, highly apolar and thiazolidine ring–containing voruscharin, accounted for 40% of leaf cardenolides, negatively predicted caterpillar growth, and was not sequestered. Using whole plants and purified voruscharin, we show that monarch caterpillars convert voruscharin to calotropin and calactin in vivo, imposing a burden on growth. As shown by in vitro experiments, this conversion is facilitated by temperature and alkaline pH. We next employed toxin-target site experiments with isolated cardenolides and the monarch’s neural Na+/K+-ATPase, revealing that voruscharin is highly inhibitory compared with several standards and sequestered cardenolides. The monarch’s typical >50-fold enhanced resistance to cardenolides compared with sensitive animals was absent for voruscharin, suggesting highly specific plant defense. Finally, oviposition was greatest on intermediate cardenolide plants, supporting the notion of a trade-off between benefits and costs of sequestration for this highly specialized herbivore. There is apparently ample opportunity for continued coevolution between monarchs and milkweeds, although the diffuse nature of the interaction, due to migration and interaction with multiple milkweeds, may limit the ability of monarchs to counteradapt.

scholarly journals Body mass index, time of day, and genetics affect perivascular spaces in the white matter

2020 ◽  
Author(s):  
Giuseppe Barisano ◽  
Farshid Sepehrband ◽  
Nasim Sheikh-Bahaei ◽  
Meng Law ◽  
Arthur W. Toga
Keyword(s):  
Body Mass Index ◽  
White Matter ◽  
Body Mass ◽  
Structural Changes ◽  
Large Population ◽  
Time Of Day ◽  
Perivascular Spaces ◽  
Healthy Human ◽  
Magnetic Resonance Imaging Mri

AbstractThe analysis of cerebral perivascular spaces (PVS) using magnetic resonance imaging (MRI) allows to explore in vivo their contributions to neurological disorders. To date the normal amount and distribution of PVS in healthy human brains are not known, thus hampering our ability to define with confidence pathogenic alterations. Furthermore, it is unclear which biological factors can influence the presence and size of PVS on MRI. We performed exploratory data analysis of PVS volume and distribution in a large population of healthy individuals (n = 897, age = 28.8 ± 3.7). Here we describe the global and regional amount of PVS in the white matter, which can be used as a reference for clinicians and researchers investigating PVS and may help the interpretation of the structural changes affecting PVS in pathological states. We found a relatively high inter-subject variability in the PVS amount in this population of healthy adults (range: 1.31-14.49 cm3). We then identified body mass index, time of day, and genetics as new elements significantly affecting PVS in vivo under physiological conditions, offering a valuable foundation to future studies aimed at understanding the physiology of perivascular flow.

Dynamics of the Tracheal Airway and Its Influences on Respiratory Airflows: An Exemplar Study

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Bora Sul ◽  
Talissa Altes ◽  
Kai Ruppert ◽  
Kun Qing ◽  
Daniel S. Hariprasad ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Minute Ventilation ◽  
Correlation Coefficients ◽  
Dynamic Imaging ◽  
Imaging Data ◽  
Cross Sectional ◽  
Mild Conditions ◽  
Large Airways ◽  
Magnetic Resonance Imaging Mri

Respiration is a dynamic process accompanied by morphological changes in the airways. Although deformation of large airways is expected to exacerbate pulmonary disease symptoms by obstructing airflow during increased minute ventilation, its quantitative effects on airflow characteristics remain unclear. Here, we used in vivo dynamic imaging and examined the effects of tracheal deformation on airflow characteristics under different conditions based on imaging data from a single healthy volunteer. First, we measured tracheal deformation profiles of a healthy lung using magnetic resonance imaging (MRI) during forced exhalation, which we simulated to characterize the subject-specific airflow patterns. Subsequently, for both inhalation and exhalation, we compared the airflows when the modeled deformation in tracheal cross-sectional area was 0% (rigid), 33% (mild), 50% (moderate), or 75% (severe). We quantified differences in airflow patterns between deformable and rigid airways by computing the correlation coefficients (R) and the root-mean-square of differences (Drms) between their velocity contours. For both inhalation and exhalation, airflow patterns were similar in all branches between the rigid and mild conditions (R > 0.9; Drms < 32%). However, airflow characteristics in the moderate and severe conditions differed markedly from those in the rigid and mild conditions in all lung branches, particularly for inhalation (moderate: R > 0.1, Drms < 76%; severe: R > 0.2, Drms < 96%). Our exemplar study supports the use of a rigid airway assumption to compute flows for mild deformation. For moderate or severe deformation, however, dynamic contraction should be considered, especially during inhalation, to accurately predict airflow and elucidate the underlying pulmonary pathology.

scholarly journals Body mass index, time of day, and genetics affect perivascular spaces in the white matter

2020 ◽  
pp. 0271678X2097285
Author(s):  
Giuseppe Barisano ◽  
Nasim Sheikh-Bahaei ◽  
Meng Law ◽  
Arthur W Toga ◽  
Farshid Sepehrband
Keyword(s):  
Body Mass Index ◽  
White Matter ◽  
Body Mass ◽  
Structural Changes ◽  
Large Population ◽  
Time Of Day ◽  
Perivascular Spaces ◽  
Healthy Human ◽  
Magnetic Resonance Imaging Mri

The analysis of cerebral perivascular spaces (PVS) using magnetic resonance imaging (MRI) allows to explore in vivo their contributions to neurological disorders. To date the normal amount and distribution of PVS in healthy human brains are not known, thus hampering our ability to define with confidence pathogenic alterations. Furthermore, it is unclear which biological factors can influence the presence and size of PVS on MRI. We performed exploratory data analysis of PVS volume and distribution in a large population of healthy individuals (n = 897, age = 28.8 ± 3.7). Here we describe the global and regional amount of PVS in the white matter, which can be used as a reference for clinicians and researchers investigating PVS and may help the interpretation of the structural changes affecting PVS in pathological states. We found a relatively high inter-subject variability in the PVS amount in this population of healthy adults (range: 1.31–14.49 cm3). The PVS volume was higher in older and male individuals. Moreover, we identified body mass index, time of day, and genetics as new elements significantly affecting PVS in vivo under physiological conditions, offering a valuable foundation to future studies aimed at understanding the physiology of perivascular flow.

Correlation of Structural Changes at Different Levels of the Jejunal Villus with Positive and Negative Net Water Transport in Vivo and in Vitro

1975 ◽  
Vol 53 (3) ◽  
pp. 439-450 ◽  
Author(s):  
T. F. McElligott ◽  
I. T. Beck ◽  
P. K. Dinda ◽  
S. Thompson
Keyword(s):  
Epithelial Cells ◽  
Water Content ◽  
Water Transport ◽  
Structural Changes ◽  
Morphological Changes ◽  
Sugar Transport ◽  
Apical Part ◽  
Different Levels

Experiments were done for identification and localization of certain structural changes at different levels of jejunal villus of the hamster during positive and negative water transport across the intestine in vivo and in vitro. Positive transport occurred when the mucosal surface of the intestine was bathed (in vitro experiments) or perfused (in vivo experiments) with isotonic Krebs–Ringer bicarbonate solution containing 10 mM glucose, and negative water transport was achieved by rendering this solution hypertonic with 150 mM mannitol. Results indicate that during positive net water transport, the intestine in vivo transported more fluid and exhibited a more conspicuous dilatation of the lateral intercellular spaces (L.I.S.) than did the in vitro preparation. Dilatation of the L.I.S. in both preparations was present only in the apical part of the villus, suggesting that this is the principal site of water absorption. When the mucosal solution was made hypertonic with mannitol, the L.I.S. in the in vivo intestine totally collapsed, whereas in the in vitro intestine these spaces remained open very slightly. These morphological changes correspond well with our finding that in the presence of the hypertonic mucosal solution there was a greater net negative water transport in vivo than in vitro. Incubation of the intestine in the isotonic mucosal solution produced subnuclear swelling of the mid-villus epithelial cells, and this morphological change was associated with an increase in the water content of the tissue. Perfusion of the in vivo intestine with the isotonic solution produced neither the swellings nor the increase in water content of the tissue. In the presence of hypertonic mucosal solution there was a water loss from the tissue both in vivo and in vitro, and these swellings were not observed. These results are discussed in relation to intestinal sugar transport and to the maturity of the epithelial cells, and it is concluded that transport studies on in vitro preparations may provide valid information on a qualitative basis, if not on a strictly quantitative basis.

NEUROIMAGING FOR THE DIAGNOSIS OF DEMENTIA

2021 ◽  
pp. 1088-1094
Author(s):  
Л. Р. Ахмадеева ◽  
Д. Э. Байков ◽  
Р. Р. Валитова ◽  
Е. В. Екушева ◽  
В. Б. Войтенков ◽  
...  
Keyword(s):  
Differential Diagnosis ◽  
Structural Changes ◽  
Lewy Body Dementia ◽  
Laboratory Diagnosis ◽  
Diagnostic Value ◽  
Amyloid Angiopathy ◽  
Diagnosis Of Dementia ◽  
Magnetic Resonance Imaging Mri ◽  
In Vivo Diagnosis

В результате совершенствования методов лабораторной диагностики и нейровизуализации стало возможным определение ряда биомаркеров, которые позволили улучшить прижизненную диагностику наиболее распространенных вариантов деменции (болезни Альцгеймера, деменции с тельцами Леви, сосудистой деменции). Структурные изменения, которые выявляются при МРТ головного мозга, являются значимыми для прогноза изменений в когнитивной сфере. Дополнительным доступным маркером, который повышает диагностическую значимость лейкоареоза и свидетельствует в пользу гипертонической микроангиопатии или церебральной амилоидной ангиопатии, является церебральное микрокровоизлияние, особенно в случаях тяжелого когнитивного дефицита и смешанной патологии. Приводится собственное наблюдение и данные цифровой гиппокампометрии как пример эффективного использования нейровизуализационных методов в дифференциальной диагностике деменции. Development of laboratory diagnosis and neuroimaging revealed some biomarkers for in vivo diagnosis of the most common forms of dementia (Alzheimer’s disease, Lewy body dementia and vascular dementia) for their differential diagnosis. Structural changes found using magnetic resonance imaging (MRI) are significant for the prognosis of the cognitive decline. Cerebral microbleeds are an available adjuvant diagnostic marker, which increases the diagnostic value of leukoaraiosis that suggests the development of cerebral amyloid angiopathy or hypertensive microangiopathy, especially in cases of mixed causes of dementia and severe cognitive deficits. We describe our own clinical case and the results of digital voxel hippocampometry as an example of effective usage of neuroimaging for the differential diagnosis of dementia.

scholarly journals Vertebrate-like CRYPTOCHROME 2 from monarch regulates circadian transcription via independent repression of CLOCK and BMAL1 activity

2017 ◽  
Vol 114 (36) ◽  
pp. E7516-E7525 ◽  
Author(s):  
Ying Zhang ◽  
Matthew J. Markert ◽  
Shayna C. Groves ◽  
Paul E. Hardin ◽  
Christine Merlin
Keyword(s):  
Danaus Plexippus ◽  
Monarch Butterfly ◽  
Constant Darkness ◽  
Transactivation Domain ◽  
C Terminus ◽  
Independent Mechanism ◽  
Reporter Assays ◽  
Cryptochrome 2 ◽  
Α Helix

Circadian repression of CLOCK-BMAL1 by PERIOD and CRYPTOCHROME (CRY) in mammals lies at the core of the circadian timekeeping mechanism. CRY repression of CLOCK-BMAL1 and regulation of circadian period are proposed to rely primarily on competition for binding with coactivators on an α-helix located within the transactivation domain (TAD) of the BMAL1 C terminus. This model has, however, not been tested in vivo. Here, we applied CRISPR/Cas9-mediated mutagenesis in the monarch butterfly (Danaus plexippus), which possesses a vertebrate-like CRY (dpCRY2) and an ortholog of BMAL1, to show that insect CRY2 regulates circadian repression through TAD α-helix–dependent and –independent mechanisms. Monarch mutants lacking the BMAL1 C terminus including the TAD exhibited arrhythmic eclosion behavior. In contrast, mutants lacking the TAD α-helix but retaining the most distal C-terminal residues exhibited robust rhythms during the first day of constant darkness (DD1), albeit with a delayed peak of eclosion. Phase delay in this mutant on DD1 was exacerbated in the presence of a single functional allele of dpCry2, and rhythmicity was abolished in the absence of dpCRY2. Reporter assays in Drosophila S2 cells further revealed that dpCRY2 represses through two distinct mechanisms: a TAD-dependent mechanism that involves the dpBMAL1 TAD α-helix and dpCLK W328 and a TAD-independent mechanism involving dpCLK E333. Together, our results provide evidence for independent mechanisms of vertebrate-like CRY circadian regulation on the BMAL1 C terminus and the CLK PAS-B domain and demonstrate the importance of a BMAL1 TAD-independent mechanism for generating circadian rhythms in vivo.

scholarly journals Airway remodeling in ferrets with cigarette smoke-induced COPD using µCT imaging

2020 ◽  
Vol 319 (1) ◽  
pp. L11-L20 ◽  
Author(s):  
Denise Stanford ◽  
Harrison Kim ◽  
Sandeep Bodduluri ◽  
Jennifer LaFontaine ◽  
Stephen A. Byzek ◽  
...  
Keyword(s):  
Chronic Bronchitis ◽  
Cigarette Smoke ◽  
Structural Changes ◽  
Morphological Changes ◽  
Airway Remodeling ◽  
Chronic Obstructive ◽  
Luminal Diameter ◽  
Bronchial Wall ◽  
Wall Area

Structural changes to airway morphology, such as increased bronchial wall thickness (BWT) and airway wall area, are cardinal features of chronic obstructive pulmonary disease (COPD). Ferrets are a recently established animal model uniquely exhibiting similar clinical and pathological characteristics of COPD as humans, including chronic bronchitis. Our objective was to develop a microcomputed tomography (µCT) method for evaluating structural changes to the airways in ferrets and assess whether the effects of smoking induce changes consistent with chronic bronchitis in humans. Ferrets were exposed to mainstream cigarette smoke or air control twice daily for 6 mo. µCT was conducted in vivo at 6 mo; a longitudinal cohort was imaged monthly. Manual measurements of BWT, luminal diameter (LD), and BWT-to-LD ratio (BWT/LD) were conducted and confirmed by a semiautomated algorithm. The square root of bronchial wall area (√WA) versus luminal perimeter was determined on an individual ferret basis. Smoke-exposed ferrets reproducibly demonstrated 34% increased BWT ( P < 0.001) along with increased LD and BWT/LD versus air controls. Regression indicated that the effect of smoking on BWT persisted despite controlling for covariates. Semiautomated measurements replicated findings. √WA for the theoretical median airway luminal perimeter of 4 mm (Pi4) was elevated 4.4% in smoke-exposed ferrets ( P = 0.015). Increased BWT and Pi4 developed steadily over time. µCT-based airway measurements in ferrets are feasible and reproducible. Smoke-exposed ferrets develop increased BWT and Pi4, changes similar to humans with chronic bronchitis. µCT can be used as a significant translational platform to measure dynamic airway morphological changes.

scholarly journals Systemic Administration of Polyelectrolyte Microcapsules: Where Do They Accumulate and When? In Vivo and Ex Vivo Study

Nanomaterials ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 812 ◽  
Author(s):  
Nikita Navolokin ◽  
Sergei German ◽  
Alla Bucharskaya ◽  
Olga Godage ◽  
Viktor Zuev ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Magnetite Nanoparticles ◽  
Ex Vivo ◽  
Morphological Changes ◽  
Morphological Structure ◽  
Intravenous Injections ◽  
Inner Organs ◽  
Distribution In Organs ◽  
Magnetic Resonance Imaging Mri

Multilayer capsules of 4 microns in size made of biodegradable polymers and iron oxide magnetite nanoparticles have been injected intravenously into rats. The time-dependent microcapsule distribution in organs was investigated in vivo by magnetic resonance imaging (MRI) and ex vivo by histological examination (HE), atomic absorption spectroscopy (AAS) and electron spin resonance (ESR), as these methods provide information at different stages of microcapsule degradation. The following organs were collected: Kidney, liver, lung, and spleen through 15 min, 1 h, 4 h, 24 h, 14 days, and 30 days after intravenous injections (IVIs) of microcapsules in a saline buffer at a dosage of 2.5 × 109 capsule per kg. The IVI of microcapsules resulted in reversible morphological changes in most of the examined inner organs (kidney, heart, liver, and spleen). The capsules lost their integrity due to degradation over 24 h, and some traces of iron oxide nanoparticles were seen at 7 days in spleen and liver structure. The morphological structure of the tissues was completely restored one month after IVI of microcapsules. Comprehensive analysis of the biodistribution and degradation of entire capsules and magnetite nanoparticles as their components gave us grounds to recommend these composite microcapsules as useful and safe tools for drug delivery applications.

scholarly journals Atrophy associated with tau pathology precedes overt cell death in a mouse model of progressive tauopathy

2020 ◽  
Vol 6 (42) ◽  
pp. eabc8098
Author(s):  
Christine W. Fung ◽  
Jia Guo ◽  
Hongjun Fu ◽  
Helen Y. Figueroa ◽  
Elisa E. Konofagou ◽  
...  
Keyword(s):  
Mouse Model ◽  
Medial Temporal Lobe ◽  
Structural Changes ◽  
Cell Loss ◽  
Temporal Association ◽  
Spatiotemporal Pattern ◽  
Resonance Imaging ◽  
Tau Pathology ◽  
Magnetic Resonance Imaging Mri

Tau pathology in Alzheimer’s disease (AD) first develops in the entorhinal cortex (EC), then spreads to the hippocampus, followed by the neocortex. Overall, tau pathology correlates well with neurodegeneration and cell loss, but the spatial and temporal association between tau pathology and overt volume loss (atrophy) associated with structural changes or cell loss is unclear. Using in vivo magnetic resonance imaging (MRI) with tensor-based morphometry (TBM), we mapped the spatiotemporal pattern of structural changes in a mouse model of AD-like progressive tauopathy. A novel, coregistered in vivo MRI atlas was then applied to identify regions in the medial temporal lobe that had a significant volume reduction. Our study shows that in a mouse model of tauopathy spread, the propagation of tau pathology from the EC to the hippocampus is associated with TBM-related atrophy, but atrophy in the dentate gyrus and subiculum precedes overt cell loss.

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