scholarly journals Diversity and evolution of amphibian pupil shapes

2021 ◽  
Author(s):  
Kate N Thomas ◽  
Caitlyn Rich ◽  
Rachel Quock ◽  
Jeffrey W Streicher ◽  
David J Gower ◽  
...  
Keyword(s):  
Larval Life ◽  
Amphibian Species ◽  
Evolutionary Mechanisms ◽  
Evolutionary Transitions ◽  
Before And After ◽  
Functional Consequences ◽  
Pupil Constriction ◽  
Ecological Mechanisms ◽  
Dim Light ◽  
Animal Vision

Pupil constriction has important functional consequences for animal vision, yet the evolutionary mechanisms underlying diverse pupil sizes and shapes, often among animals that occupy optically similar environments, are poorly understood. We aimed to quantify the diversity and evolution of pupil shapes among amphibians and test for potential correlations to ecology based on functional hypotheses. Using photographs, we surveyed pupil shape and the orientation of the constricted pupil across adults of 1293 amphibian species, 72 families, and 3 orders, and additionally for larval life stages for all families of frogs and salamanders with a biphasic ontogeny. Pupil shape is exceptionally diverse in amphibians with evolutionary transitions throughout the amphibian tree of life. For amphibians with a biphasic life history, we found that pupils change in many species that occupy distinct habitats before and after metamorphosis. Finally, we found that non-elongated (round or diamond) constricted pupils were correlated with species inhabiting consistently dim light environments (burrowing and aquatic species) and that elongated pupils (vertical and horizontal) were more common in species with larger absolute eye sizes. We propose that amphibians provide a valuable group within which to explore the anatomical, physiological, optical, and ecological mechanisms underlying the evolution of pupil shape.

Evolutionary Transitions in Mode of Development

2018 ◽  
Keyword(s):  
Analytical Approach ◽  
Large Body ◽  
Functional Variation ◽  
Evolutionary Mechanisms ◽  
Evolutionary Transitions ◽  
Comparative Phylogenetics ◽  
Mode Of Development ◽  
Larval Traits ◽  
Complex Characters

In the large body of literature on ecological and evolutionary mechanisms underlying transitions between planktotrophy and lecithotrophy, the focus has typically covered long evolutionary timescales; that is, evolution of complex larval traits is generally discussed in the context of phylogenetic patterns detectable at the level of families, classes, or phyla. An analytical approach incorporating comparative phylogenetics is increasingly used to address these long-view questions. Here, we discuss what has been learned from taking a comparative phylogenetic approach and the limitations of this approach. We propose that approaches based on a closer view—that is, analyses that focus on genetic, morphological, and functional variation among individuals, populations, or closely related congeners—have greater potential to answer questions about mechanisms underlying the loss and regain of major complex characters such as feeding larvae.

Clinical mucositis and intestinal permeability abnormalities in metastatic colorectal cancer patients treated with irinotecan and 5-fluoruracil.

2012 ◽  
Vol 30 (15_suppl) ◽  
pp. e14183-e14183 ◽  
Author(s):  
Markus Gifoni ◽  
Roberto Cesar Lima ◽  
Aldo Angelo Moreira Lima ◽  
Adriana Facanha ◽  
Rodrigo Barbosa Callado ◽  
...  
Keyword(s):  
Intestinal Permeability ◽  
Serum Levels ◽  
Wilcoxon Test ◽  
Permeability Test ◽  
Invasive Test ◽  
Before And After ◽  
Functional Consequences ◽  
Gastrointestinal Mucositis ◽  
Pain Symptoms ◽  
Almost All

e14183 Background: The comprehension of the mechanisms involved in the adverse events of the cytotoxic drugs available to treat metastatic colorctal cancer (CRC) is necessary to improve their efficacy and safety. The irinotecan, fluoruracil and folinic acid (IFL) bolus regimen have as its major toxicity issue the complex and multi-mediated gastrointestinal mucositis. Nevertheless, it is difficult to obtain a reliable measurement of the intestinal abnormalities and functional consequences caused by intestinal mucositis, as almost all the clinical data available are reported on a patient symptoms-based scale analysis. Methods: With the lactulose/ mannitol permeability test as the experimental platform, we did a prospective case control study with 25 metastatic CRC patients treated with first line IFL. The primary end point was to compare (Wilcoxon test) the lactulose/ mannitol permeability test before the treatment and the same patients tests at the 15th and 29th day of the first IFL cycle. Blood samples of the same individuals were obtained before the treatment and at 15th day of their first IFL cycle to compare the ELISA serum levels of potentially involved cytokines (TNFα, IL-1β, IL-6, IL-18, IL-18bp e IL-33) (paired t-test). Results: In contrast with the pretreatment controls, the lactulose/ mannitol ratio was significantly (p<0,05) increased at the D15 and D29 in patients taking the first IFL cycle. The mannitol excretion rate was also decreased (p<0,05) at the 29th day. This abnormalities also reserve significant (p<0,05 – Spearman coeficient) correlation with the diarrhea and abdominal pain symptoms (NCI-CTC version 4.0) scale reported by the patients. Otherwise, it has not been possible to demonstrate serum levels differences of the addressed cytokines before and after the treatment. Conclusions: The lactulose/ mannitol permeability test is an objective and reliable tool to measure intestinal permeability abnormalities secondary to gastrointestinal mucositis caused by IFL to metastatic CRC patients.This non-invasive test could bring more objetctive measurement of the functional consequences of this limiting toxicity.

scholarly journals The Effect of Cognitive Behaviour Therapy on Sleep and Circadian Rhythm in Young College Students

2021 ◽  
pp. 43-47
Author(s):  
Shweta Kanchan ◽  
Sunita Tiwari ◽  
Shweta Singh
Keyword(s):  
Cognitive Behaviour Therapy ◽  
Sleep Time ◽  
Behaviour Therapy ◽  
Circadian Phase ◽  
Dim Light Melatonin Onset ◽  
College Going ◽  
Cognitive Behaviour ◽  
Before And After ◽  
Sleep Parameters ◽  
Dim Light

The present study is to study the effect of cognitive behaviour therapy on various sleep parameters and circadian phase rhythmic in young college going adults. Fifty young college going adults were chosen from the MBBS and BDS students of King George's Medical University Lucknow, their polysomnography was conducted along with it salivary melatonin estimation was conducted to find the time of Dim light melatonin onset (DLMO), the subjects were administered cognitive behaviour therapy (CBT),after completing the sessions of cognitive behaviour therapy another Polysomnographic study and DLMO estimation was conducted, various sleep parameters were compared before and after the CBT. The study showed an improvement in the steep quality, a decrease in daytime sleepiness along with this total sleep time significantly increased, sleep efficiency also improved and there was a decrease in the REM sleep latency. The Dim light melatonin onset advanced for the subjects and the chronotype showed an inclination towards an earlier timings.

Mechanisms of tongue protraction and narial closure in the marine toad Bufo marinus.

1996 ◽  
Vol 199 (11) ◽  
pp. 2511-2529 ◽  
Author(s):  
K C Nishikawa ◽  
C Gans
Keyword(s):  
Prey Capture ◽  
Morphological Evolution ◽  
Neuromuscular Control ◽  
Bufo Marinus ◽  
Forward Movement ◽  
External Reference ◽  
Before And After ◽  
Functional Consequences ◽  
Two Phases ◽  
Toad Bufo

Electromyography, kinematic analysis, muscle stimulation and denervation techniques were used to investigate the muscular mechanisms of narial closure during breathing and of tongue protraction during prey capture in the marine toad Bufo marinus. Toads were video-taped during breathing and feeding under a variety of conditions: before surgery, after unilateral or bilateral denervation of the M. submentalis, and after unilateral or bilateral denervation of the Mm. genioglossus basalis and medialis. Deeply anesthetized toads were video-taped during stimulation of several cranial muscles, and electromyograms were recorded from the M. submentalis during feeding before and after its denervation. Bufo marinus differs from many other anurans in having a relatively long tongue that experiences large accelerations (&gt; 31 g) during protraction. Tongue protraction occurs in two phases: an early phase during which the lingual tip moves upward and forward relative to the mandibular tip as the tongue shortens, and a later phase during which the lingual tip moves downward and forward relative to the mandibular tip as the tongue elongates under its own momentum. Relative to an external reference, the lingual tip follows a straight trajectory from mouth to prey, which depends critically upon precise coordination of tongue and jaw movements. The M. submentalis is necessary for normal tongue protraction during feeding. In contrast, the Mm. genioglossus basalis and medialis are necessary for forward movement of the tongue pad over the symphysis. In B. marinus, a simple anatomical change (elongation of the tongue) has functional consequences (inertial elongation) that profoundly affect the mechanisms of neuromuscular control. Though seldom studied, it seems likely that morphological evolution has had a profound influence on mechanisms of motor control in animals generally.

scholarly journals Allopatric origins of microbial species

2006 ◽  
Vol 361 (1475) ◽  
pp. 1975-1984 ◽  
Author(s):  
Rachel J Whitaker
Keyword(s):  
Microbial Populations ◽  
Dynamic Processes ◽  
Microbial World ◽  
Evolutionary Mechanisms ◽  
Microbial Species ◽  
Great Debate ◽  
Genomic Tools ◽  
Allopatric Divergence ◽  
Ecological Mechanisms ◽  
Micro Organisms

Although allopatric divergence is a well-accepted mechanism of speciation for eukaryotic macro-organisms, the importance of geographical barriers to divergence in microbial populations is a subject of great debate. Do geographically separated populations of micro-organisms diverge independently, or does their structure fit the often quoted Bass-Becking description ‘everything is everywhere; the environment selects’? Aided by high-resolution genetic and genomic tools, the search for ‘microbial marsupials’ has revealed that in fact both are true; some species of micro-organisms demonstrate allopatric divergence, while others do not. This discovery opens the door for comparative analyses, where questions about the differences in evolutionary and ecological mechanisms that drive divergence and speciation in different microbial species can begin to be explored. Investigating these differences in evolutionary mechanisms will greatly enhance interest in, and understanding of, the dynamic processes that create and maintain the vast diversity of the microbial world.

scholarly journals Substantial Achilles adaptation following strength training has no impact on tendon function during walking

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0255221
Author(s):  
C. M. Waugh ◽  
A. Scott
Keyword(s):  
Strength Training ◽  
Statistical Tests ◽  
Statistical Parametric Mapping ◽  
Training Adaptations ◽  
Before And After ◽  
Functional Consequences ◽  
Tendon Adaptation ◽  
Stretch Shortening Cycle

Tendons are responsive to mechanical loading and their properties are often the target of intervention programs. The tendon’s mechanical properties, particularly stiffness, also govern its function, therefore changes to these properties could have substantial influence on energy-saving mechanisms during activities utilizing the stretch-shortening cycle. We investigated Achilles tendon (AT) function in vivo during walking with respect to a training intervention that elicited significant increases in AT stiffness. 14 men and women completed 12-weeks of isometric plantarflexor strength training that increased AT stiffness, measured during isometric MVC, by ~31%. Before and after the intervention, participants walked shod at their preferred velocity on a fully-instrumented treadmill. Movement kinematics, kinetics and displacement of the gastrocnemius medialis muscle-tendon junction were captured synchronously using 3D motion capture and ultrasound imaging, respectively. A MANOVA test was used to examine changes in AT force, stress, strain, stiffness, Young’s modulus, hysteresis and strain energy, measured during walking, before and following strength training. All were non-significant for a main effect of time, therefore no follow-up statistical tests were conducted. Changes in joint kinematics, tendon strain, velocity, work and power and muscle activity during the stance phase were assessed with 1D statistical parametric mapping, all of which also demonstrated a lack of change in response to the intervention. This in vivo examination of tendon function in walking provides an important foundation for investigating the functional consequences of training adaptations. We found substantial increases in AT stiffness did not impact on tendon function during walking. AT stiffness measured during walking, however, was unchanged with training, which suggests that increases in stiffness may not be evident across the whole force-elongation relation, a finding which may help explain previously mixed intervention results and guide future investigations in the functional implications of tendon adaptation.

scholarly journals Genome-Wide SNP Analysis of Male and Female Rice Field Frogs, Hoplobatrachus rugulosus, Supports a Non-Genetic Sex Determination System

Diversity ◽  
2021 ◽  
Vol 13 (10) ◽  
pp. 501
Author(s):  
Thitipong Panthum ◽  
Worapong Singchat ◽  
Nararat Laopichienpong ◽  
Syed Farhan Ahmad ◽  
Ekaphan Kraichak ◽  
...  
Keyword(s):  
Sex Determination ◽  
Rice Field ◽  
Sex Chromosome ◽  
The Body ◽  
Threshold Temperature ◽  
Snp Analysis ◽  
Amphibian Species ◽  
Evolutionary Transitions ◽  
Evolutionary Trap ◽  
Sex Determination System

Sex determination systems (SDSs) in anurans are diverse and have undergone independent evolutionary transitions among species. The mode of sexual reproduction of the rice field frog (Hoplobatrachus rugulosus)—an economically viable, edible amphibian species—is not well known. Previous studies have proposed that threshold temperature conditions may determine sex in these frogs. To elucidate the SDS in H. rugulosus, we karyotyped 10 male and 12 female frogs, and performed fluorescence in situ hybridization combined with sequencing analyses using DArTseq™. Our results revealed a highly conserved karyotype with no sex chromosome heteromorphism, and the sequencing analyses did not identify any consistent sex-linked loci, supporting the hypothesis of temperature-dependent sex determination. The results of this study, and others, on SDSs in the rice field frog and related species also provide support for the theory that heteromorphic sex chromosomes may lead to an evolutionary trap that prevents variable SDSs. These findings add important information to the body of knowledge on H. rugulosus and are likely to have a significant impact on the productivity and economic success of rice field frog farming.

scholarly journals Checklist of amphibians in a transitional area between the Caatinga and the Atlantic Forest, central-southern Bahia, Brazil

Check List ◽  
2013 ◽  
Vol 9 (4) ◽  
pp. 725 ◽  
Author(s):  
Amanda S. F. Lantyer Silva ◽  
Sérgio Siqueira Júnior ◽  
Juliana Zina
Keyword(s):  
Transition Zone ◽  
Atlantic Forest ◽  
Pitfall Traps ◽  
Community Structures ◽  
Amphibian Species ◽  
Transitional Area ◽  
Active Search ◽  
Reproductive Modes ◽  
Southern Bahia ◽  
Ecological Mechanisms

We present a list of amphibian species from Serra do Brejo Novo, municipality of Jequié, state of Bahia in Brazil, a transition zone between the Caatinga and the Atlantic Forest that encompasses a great diversity of species and reproductive modes. Between November 2009 and April 2010 we surveyed the area using pitfall traps and between August 2010 and February 2012 data was collected using active search methodology. We recorded 32 species belonging to seven families. The unexpected composition of species and reproductive modes of this community highlight the importance of species inventories and also the need for exploring transitional areas to understand the ecological mechanisms responsible for changes in community structures between different zones.

scholarly journals Morning impairment in vascular function is unrelated to overnight sleep or the inactivity that accompanies sleep

2018 ◽  
Vol 315 (5) ◽  
pp. R986-R993 ◽  
Author(s):  
Saurabh S. Thosar ◽  
Alec M. Berman ◽  
Maya X. Herzig ◽  
Sally A. Roberts ◽  
Michael R. Lasarev ◽  
...  
Keyword(s):  
Vascular Function ◽  
Physical Inactivity ◽  
Flow Mediated Dilation ◽  
Vascular Endothelial ◽  
Endothelin 1 ◽  
System A ◽  
Before And After ◽  
Markers Of Oxidative Stress ◽  
Dim Light ◽  
Healthy Participants

Adverse cardiovascular events, such as myocardial infarction and sudden cardiac death, occur more frequently in the morning. Prior studies have shown that vascular endothelial function (VEF), a marker of cardiovascular disease, is attenuated during physical inactivity and declines across the night. We sought to determine whether a morning attenuation in VEF is a result of prior sleep or the inactivity that inevitably accompanies sleep. After 1 wk of a rigorously controlled sleep-wake schedule and behaviors, 10 healthy participants completed a randomized crossover protocol in dim light and constant conditions, incorporating a night of 6 h of sleep opportunity and a night of immobility while they were supine and awake. VEF was measured in the dominant brachial artery as flow mediated dilation (FMD) before and after each 6-h trial. To avoid disturbing sleep and posture of the participants, blood was drawn using a 12-ft catheter from an adjoining laboratory room before, during, and after each 6-h trial, and plasma was analyzed for markers of oxidative stress [malondialdehyde adducts (MDA)], and endothelin-1. Contrary to expectation, both nocturnal sleep and nocturnal inactivity significantly increased FMD ( P < 0.05). There was no significant change in MDA or endothelin-1 within and between trials. Contrary to expectations based on prior studies, we found that overnight sleep or the inactivity that accompanies sleep did not result in attenuation in VEF in the morning hours in healthy people. Thus, it is plausible that the endogenous circadian system, a remaining factor not studied here, is responsible for the commonly observed decline in VEF across the night.

scholarly journals EXPLORING THE DYNAMICS DURING COMMUNITY ASSEMBLY THROUGH COMMUNITY PHYLOGENETICS

TREUBIA ◽  
2015 ◽  
Vol 42 ◽  
pp. 37
Author(s):  
Rena Tri Hernawati ◽  
Daisy Wowor ◽  
Nicolas Hubert
Keyword(s):  
Community Assembly ◽  
Evolutionary Dynamics ◽  
Empirical Studies ◽  
Regional Scale ◽  
Ecological Community ◽  
Evolutionary Mechanisms ◽  
Spatial And Temporal Scales ◽  
Spatial Framework ◽  
Approaches To Study ◽  
Ecological Mechanisms

Species diversify through speciation and accumulate in ecological community, a process known as community assembly. Relying on both evolutionary mechanisms acting at regional scale and ecological mechanisms acting at local scale, the process of community assembly results from intricate interactions among mechanisms at play across varying spatial and temporal scales. During the last decade, community assembly theory has been reconsidered in the light of evolutionary dynamics of species diversification and ecological dynamics have been formalized in an explicit spatial framework (i.e. metacommunity theory). The aims of the present review are: (1) to present the community assembly theory and the main paradigms that have been proposed, (2) to discuss how the metacommunity theory as defined an explicit spatial framework for community ecology, (3)to discuss the potential mechanisms at play during community assembly and their associated predictions, (4) to present new approaches to study community assembly based on phylogenetics approaches and discuss how they have been integrated in empirical studies.

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