scholarly journals Molecular mechanisms underlying nuchal hump formation in dolphin cichlid, Cyrtocara moorii

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Laurène Alicia Lecaudey ◽  
Christian Sturmbauer ◽  
Pooja Singh ◽  
Ehsan Pashay Ahi
Keyword(s):  
Central America ◽  
Adaptive Radiation ◽  
Expression Profiling ◽  
Molecular Mechanisms ◽  
Soft Tissues ◽  
Molecular Level ◽  
Teleost Fishes ◽  
East African ◽  
Rapid Speciation ◽  
Adaptive Radiations

AbstractEast African cichlid fishes represent a model to tackle adaptive changes and their connection to rapid speciation and ecological distinction. In comparison to bony craniofacial tissues, adaptive morphogenesis of soft tissues has been rarely addressed, particularly at the molecular level. The nuchal hump in cichlids fishes is one such soft-tissue and exaggerated trait that is hypothesized to play an innovative role in the adaptive radiation of cichlids fishes. It has also evolved in parallel across lakes in East Africa and Central America. Using gene expression profiling, we identified and validated a set of genes involved in nuchal hump formation in the Lake Malawi dolphin cichlid, Cyrtocara moorii. In particular, we found genes differentially expressed in the nuchal hump, which are involved in controlling cell proliferation (btg3, fosl1a and pdgfrb), cell growth (dlk1), craniofacial morphogenesis (dlx5a, mycn and tcf12), as well as regulators of growth-related signals (dpt, pappa and socs2). This is the first study to identify the set of genes associated with nuchal hump formation in cichlids. Given that the hump is a trait that evolved repeatedly in several African and American cichlid lineages, it would be interesting to see if the molecular pathways and genes triggering hump formation follow a common genetic track or if the trait evolved in parallel, with distinct mechanisms, in other cichlid adaptive radiations and even in other teleost fishes.

scholarly journals Cranial shape evolution in adaptive radiations of birds: comparative morphometrics of Darwin's finches and Hawaiian honeycreepers

2017 ◽  
Vol 372 (1713) ◽  
pp. 20150481 ◽  
Author(s):  
Masayoshi Tokita ◽  
Wataru Yano ◽  
Helen F. James ◽  
Arhat Abzhanov
Keyword(s):  
Adaptive Radiation ◽  
Molecular Mechanisms ◽  
Rapid Evolution ◽  
Oceanic Islands ◽  
Shape Variation ◽  
Skull Morphology ◽  
Darwin's Finches ◽  
Hawaiian Honeycreepers ◽  
Darwin’S Finches ◽  
Adaptive Radiations

Adaptive radiation is the rapid evolution of morphologically and ecologically diverse species from a single ancestor. The two classic examples of adaptive radiation are Darwin's finches and the Hawaiian honeycreepers, which evolved remarkable levels of adaptive cranial morphological variation. To gain new insights into the nature of their diversification, we performed comparative three-dimensional geometric morphometric analyses based on X-ray microcomputed tomography (µCT) scanning of dried cranial skeletons. We show that cranial shapes in both Hawaiian honeycreepers and Coerebinae (Darwin's finches and their close relatives) are much more diverse than in their respective outgroups, but Hawaiian honeycreepers as a group display the highest diversity and disparity of all other bird groups studied. We also report a significant contribution of allometry to skull shape variation, and distinct patterns of evolutionary change in skull morphology in the two lineages of songbirds that underwent adaptive radiation on oceanic islands. These findings help to better understand the nature of adaptive radiations in general and provide a foundation for future investigations on the developmental and molecular mechanisms underlying diversification of these morphologically distinguished groups of birds. This article is part of the themed issue ‘Evo-devo in the genomics era, and the origins of morphological diversity’.

scholarly journals Radula diversification promotes ecomorph divergence in an adaptive radiation of freshwater snails

2020 ◽  
Author(s):  
Leon Hilgers ◽  
Stefanie Hartmann ◽  
Jobst Pfaender ◽  
Nora Lentge-Maaß ◽  
Thomas von Rintelen ◽  
...  
Keyword(s):  
Adaptive Radiation ◽  
Complex Traits ◽  
Molecular Basis ◽  
Molecular Mechanisms ◽  
Freshwater Snail ◽  
Freshwater Snails ◽  
Trophic Specialization ◽  
Adaptive Diversification ◽  
Adaptive Radiations ◽  
Lineage Divergence

AbstractAdaptive diversification of complex traits plays a pivotal role for the evolution of organismal diversity. However, the underlying molecular mechanisms remain largely elusive. In the freshwater snail genus Tylomelania, adaptive radiations were likely promoted by trophic specialization via diversification of their key foraging organ, the radula. To investigate the molecular basis of radula diversification and its contribution to lineage divergence, we use pooled tissue-specific transcriptomes of two sympatric Tylomelania sarasinorum ecomorphs. We show that divergence in both gene expression and coding sequences is stronger between radula transcriptomes compared to mantle and foot transcriptomes. These findings support the hypothesis that diversifying selection on the radula is driving speciation in Tylomelania radiations. We also identify several candidate genes for radula divergence. Putative homologs of some candidates (hh, arx, gbb) also contributed to trophic specialization in cichlids and Darwin’s finches, indicating that some molecular pathways may be especially prone to adaptive diversification.

scholarly journals Genetic basis of body shape variation along the benthic-pelagic axis in cichlid fishes

2021 ◽  
Author(s):  
Leah DeLorenzo ◽  
Destiny Mathews ◽  
A. Allyson Brandon ◽  
Mansi Joglekar ◽  
Aldo Carmona Baez ◽  
...  
Keyword(s):  
Adaptive Radiation ◽  
Body Shape ◽  
Genetic Basis ◽  
Molecular Mechanisms ◽  
Lake Malawi ◽  
Shape Variation ◽  
East African ◽  
Cichlid Fishes ◽  
African Rift ◽  
Two Hybrid

Divergence along the benthic-pelagic axis is one of the most widespread and repeated patterns of morphological variation in fishes, producing body shape diversity associated with ecology and swimming mechanics. This ecological shift is also the first stage of the explosive adaptive radiation of cichlid fishes in the East African Rift Lakes. We use two hybrid crosses of cichlids (Metriaclima sp. x Aulonocara sp. and Labidochromis sp. x Labeotropheus sp., >975 animals total) along the benthic-pelagic ecomorphological axis to determine the genetic basis of body shape diversification. Using a series of both linear and geometric shape measurements, we identify 55 quantitative trait loci (QTL) that underlie various aspects of body shape variation associated with benthic-pelagic divergence. These QTL are spread throughout the genome, each explain 3.0-7.2% of phenotypic variation, and are largely modular. Further, QTL are distinct both between these two crosses of Lake Malawi cichlids and compared to previously identified QTL for body shape in fishes such as sticklebacks. We find that body shape is controlled by many genes of small effects. In all, we find that convergent benthic and pelagic body phenotypes commonly observed across fish clades are most likely due to distinct genetic and molecular mechanisms.

scholarly journals Continental cichlid radiations: functional diversity reveals the role of changing ecological opportunity in the Neotropics

2016 ◽  
Vol 283 (1836) ◽  
pp. 20160556 ◽  
Author(s):  
Jessica Hilary Arbour ◽  
Hernán López-Fernández
Keyword(s):  
Central America ◽  
Adaptive Radiation ◽  
Morphological Diversity ◽  
Evolutionary Rates ◽  
Ecological Niches ◽  
Ecological Opportunity ◽  
Ecological Release ◽  
Adaptive Radiations ◽  
Lineage Diversification

Adaptive radiations have been hypothesized to contribute broadly to the diversity of organisms. Models of adaptive radiation predict that ecological opportunity and ecological release, the availability of empty ecological niches and the response by adapting lineages to occupy them, respectively, drive patterns of phenotypic and lineage diversification. Adaptive radiations driven by ‘ecological opportunity’ are well established in island systems; it is less clear if ecological opportunity influences continent-wide diversification. We use Neotropical cichlid fishes to test if variation in rates of functional evolution is consistent with changing ecological opportunity. Across a functional morphological axis associated with ram–suction feeding traits, evolutionary rates declined through time as lineages diversified in South America. Evolutionary rates of ram–suction functional morphology also appear to have accelerated as cichlids colonized Central America and encountered renewed opportunity. Our results suggest that ecological opportunity may play an important role in shaping patterns of morphological diversity of even broadly distributed lineages like Neotropical cichlids.

scholarly journals Molecular remission at T cell level in patients with rheumatoid arthritis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jun Inamo ◽  
Katsuya Suzuki ◽  
Masaru Takeshita ◽  
Yasushi Kondo ◽  
Yuumi Okuzono ◽  
...  
Keyword(s):  
Rheumatoid Arthritis ◽  
T Cells ◽  
T Cell ◽  
Disease Control ◽  
Expression Profiling ◽  
Molecular Mechanisms ◽  
Principal Component ◽  
Cell Level ◽  
Molecular Remission ◽  
Signature Genes

AbstractWhile numerous disease-modifying anti-rheumatic drugs (DMARDs) have brought about a dramatic paradigm shift in the management of rheumatoid arthritis (RA), unmet needs remain, such as the small proportion of patients who achieve drug-free status. The aim of this study was to explore key molecules for remission at the T cell level, which are known to be deeply involved in RA pathogenesis, and investigate the disease course of patients who achieved molecular remission (MR). We enrolled a total of 46 patients with RA and 10 healthy controls (HCs). We performed gene expression profiling and selected remission signature genes in CD4+ T cells and CD8+ T cells from patients with RA using machine learning methods. In addition, we investigated the benefits of achieving MR on disease control. We identified 9 and 23 genes that were associated with clinical remission in CD4+ and CD8+ T cells, respectively. Principal component analysis (PCA) demonstrated that their expression profiling was similar to those in HCs. For the remission signature genes in CD4+ T cells, the PCA result was reproduced using a validation cohort, indicating the robustness of these genes. A trend toward better disease control was observed during 12 months of follow-up in patients treated with tocilizumab in deep MR compared with those in non-deep MR, although the difference was not significant. The current study will promote our understanding of the molecular mechanisms necessary to achieve deep remission during the management of RA.

scholarly journals Emerging Data on the Diversity of Molecular Mechanisms Involving C/D snoRNAs

2021 ◽  
Vol 7 (2) ◽  
pp. 30
Author(s):  
Laeya Baldini ◽  
Bruno Charpentier ◽  
Stéphane Labialle
Keyword(s):  
Ribosomal Rna ◽  
Molecular Mechanisms ◽  
Molecular Level ◽  
Accurate Description ◽  
Small Nucleolar Rnas ◽  
Age Of Maturity ◽  
Non Coding Rnas ◽  
And Function ◽  
Nucleolar Rnas

Box C/D small nucleolar RNAs (C/D snoRNAs) represent an ancient family of small non-coding RNAs that are classically viewed as housekeeping guides for the 2′-O-methylation of ribosomal RNA in Archaea and Eukaryotes. However, an extensive set of studies now argues that they are involved in mechanisms that go well beyond this function. Here, we present these pieces of evidence in light of the current comprehension of the molecular mechanisms that control C/D snoRNA expression and function. From this inventory emerges that an accurate description of these activities at a molecular level is required to let the snoRNA field enter in a second age of maturity.

scholarly journals Adaptive radiation and hybridization in Wallace's Dreamponds: evidence from sailfin silversides in the Malili Lakes of Sulawesi

2006 ◽  
Vol 273 (1598) ◽  
pp. 2209-2217 ◽  
Author(s):  
Fabian Herder ◽  
Arne W Nolte ◽  
Jobst Pfaender ◽  
Julia Schwarzer ◽  
Renny K Hadiaty ◽  
...  
Keyword(s):  
New Species ◽  
Adaptive Radiation ◽  
Introgressive Hybridization ◽  
Reticulate Evolution ◽  
Species Group ◽  
Potential Force ◽  
Major Interest ◽  
Key Factor ◽  
Adaptive Radiations ◽  
Malili Lakes

Adaptive radiations are extremely useful to understand factors driving speciation. A challenge in speciation research is to distinguish forces creating novelties and those relevant to divergence and adaptation. Recently, hybridization has regained major interest as a potential force leading to functional novelty and to the genesis of new species. Here, we show that introgressive hybridization is a prominent phenomenon in the radiation of sailfin silversides (Teleostei: Atheriniformes: Telmatherinidae) inhabiting the ancient Malili Lakes of Sulawesi, correlating conspicuously with patterns of increased diversity. We found the most diverse lacustrine species-group of the radiation to be heavily introgressed by genotypes originating from streams of the lake system, an effect that has masked the primary phylogenetic pattern of the flock. We conclude that hybridization could have acted as a key factor in the generation of the flock's spectacular diversity. To our knowledge, this is the first empirical evidence for massive reticulate evolution within a complex animal radiation.

scholarly journals Desethylamiodarone antagonizes the effect of thyroid hormone at the molecular level

2001 ◽  
pp. 59-64 ◽  
Author(s):  
F Bogazzi ◽  
L Bartalena ◽  
S Brogioni ◽  
A Burelli ◽  
F Raggi ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Molecular Mechanisms ◽  
Thyroid Hormone Receptor ◽  
Molecular Level ◽  
Inhibitory Effect ◽  
Mobility Shift ◽  
Down Regulation ◽  
Nih3t3 Cells ◽  
Peripheral Tissues

OBJECTIVE: To evaluate the molecular mechanisms of the inhibitory effects of amiodarone and its active metabolite, desethylamiodarone (DEA) on thyroid hormone action. MATERIALS AND METHODS: The reporter construct ME-TRE-TK-CAT or TSHbeta-TRE-TK-CAT, containing the nucleotide sequence of the thyroid hormone response element (TRE) of either malic enzyme (ME) or TSHbeta genes, thymidine kinase (TK) and chloramphenicol acetyltransferase (CAT) was transiently transfected with RSV-TRbeta into NIH3T3 cells. Gel mobility shift assay (EMSA) was performed using labelled synthetic oligonucleotides containing the ME-TRE and in vitro translated thyroid hormone receptor (TR)beta. RESULTS: Addition of 1 micromol/l T4 or T3 to the culture medium increased the basal level of ME-TRE-TK-CAT by 4.5- and 12.5-fold respectively. Amiodarone or DEA (1 micromol/l) increased CAT activity by 1.4- and 3.4-fold respectively. Combination of DEA with T4 or T3 increased CAT activity by 9.4- and 18.9-fold respectively. These data suggested that DEA, but not amiodarone, had a synergistic effect with thyroid hormone on ME-TRE, rather than the postulated inhibitory action; we supposed that this was due to overexpression of the transfected TR into the cells. When the amount of RSV-TRbeta was reduced until it was present in a limited amount, allowing competition between thyroid hormone and the drug, addition of 1 micromol/l DEA decreased the T3-dependent expression of the reporter gene by 50%. The inhibitory effect of DEA was partially due to a reduced binding of TR to ME-TRE, as assessed by EMSA. DEA activated the TR-dependent down-regulation by the negative TSH-TRE, although at low level (35% of the down-regulation produced by T3), whereas amiodarone was ineffective. Addition of 1 micromol/l DEA to T3-containing medium reduced the T3-TR-mediated down-regulation of TSH-TRE to 55%. CONCLUSIONS: Our results demonstrate that DEA, but not amiodarone, exerts a direct, although weak, effect on genes that are regulated by thyroid hormone. High concentrations of DEA antagonize the action of T3 at the molecular level, interacting with TR and reducing its binding to TREs. This effect may contribute to the hypothyroid-like effect observed in peripheral tissues of patients receiving amiodarone treatment.

Age-associated features of the expression level of apoptosis markers in cardiomyocytes of patients with dilated cardiomyopathy

2022 ◽  
pp. 885-890
Author(s):  
К.П. Кравченко ◽  
К. Л. Козлов ◽  
А.О. Дробинцева ◽  
Д.С. Медведев ◽  
В.О. Полякова
Keyword(s):  
Cell Death ◽  
Dilated Cardiomyopathy ◽  
Molecular Mechanisms ◽  
Molecular Level ◽  
Confocal Laser ◽  
Control Group ◽  
Cellular Mechanisms ◽  
Apoptosis Pathway ◽  
Bax Protein

Для понимания патогенеза дилатационной кардиомиопатии (ДКМП) необходимо установить молекулярно-клеточные механизмы старения миокарда, в том числе связанные с программируемой клеточной гибелью, молекулярные механизмы которого практически не изучены. Цель работы - изучение маркеров апоптоза в кардиомиоцитах у пациентов с ДКМП in vitro. В работе использовали метод первичных диссоциированных клеточных культур и метод иммунофлюоресцентной конфокальной лазерной микроскопии. Для моделирования клеточного старения использовали клетки 3-го и 14-го пассажей, соответствующие «молодым» и «старым» культурам. На молекулярном уровне старение клеток кардиомиоцитов сопровождалось повышением экспрессии р16 в 2 раза по сравнению с «молодыми культурами» как в контрольной, так и в группе с ДКМП. Также установлено, что экспрессия р16 в культурах, взятых от пациентов с патологией, была в 2 раза выше, чем в аналогичных культурах от здоровых пациентов. Экспрессия р21 была повышена в группе с ДКМП по сравнению с контрольной группой, однако при старении культуры экспрессия p21 не изменялась, оставаясь на высоком уровне. Наиболее значимые различия были получены при сравнении экспрессии Bax в культуре клеток кардиомиоцитов из группы с ДКМП в «молодой» культуре с нормой - в 3,2 раза. Старение клеток миокарда на молекулярном уровне проявлялось в повышении экспрессии белка Baх, именно он является запускающим механизмом митохондриального пути апоптоза. Возможно, этот путь клеточной гибели является превалирующем при ДКМП. To understand the pathogenesis of dilated cardiomyopathy (DCMP), it is necessary to establish the molecular-cellular mechanisms of myocardial aging, including those associated with programmed cell death, the molecular mechanisms of which have not been practically studied. The aim of this work is to study markers of apoptosis in cardiomyocytes of patients with DCMP in vitro. We used the method of primary dissociated cell cultures and the method of immunofluorescence confocal laser microscopy. Cells of the 3 and 14 passages, corresponding to «young» and «old» cultures, were used to simulate cellular senescence. Results. At the molecular level, aging of cardiomyocyte cells was accompanied by a twofold increase in the expression of p16 compared to «young cultures» both in the control group and in the group with DCMP. It was also found that the expression of p16 in cultures taken from patients with pathology was 2 times higher than in similar cultures from healthy patients. The expression of p21 was increased in the group with DCMP compared to the control; however, with aging of the culture, the expression of p21 did not change, remaining at a significant level. The most significant differences were obtained when comparing the expression of Bax in the cell culture of cardiomyocytes from the group with DCMP in a «young» culture compared with the norm, 3,2 times. Aging of myocardial cells at the molecular level was manifested in an increase in the expression of the Bax protein, which is the triggering mechanism of the mitochondrial apoptosis pathway. It is possible that this pathway of cell death is prevalent in DCMP.

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