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Frontiers in Cell and Developmental... 2021Chordates are divided into three subphyla: Vertebrata, Tunicata, and Cephalochordata. Phylogenetically, the Cephalochordata, more commonly known as lancelets or...
Chordates are divided into three subphyla: Vertebrata, Tunicata, and Cephalochordata. Phylogenetically, the Cephalochordata, more commonly known as lancelets or amphioxus, constitute the sister group of Vertebrata and Tunicata. Lancelets are small, benthic, marine filter feeders, and their roughly three dozen described species are divided into three genera: , , and . Due to their phylogenetic position and their stereotypical chordate morphology and genome architecture, lancelets are key models for understanding the evolutionary history of chordates. Lancelets have thus been studied by generations of scientists, with the first descriptions of adult anatomy and developmental morphology dating back to the 19th century. Today, several different lancelet species are used as laboratory models, predominantly for developmental, molecular and genomic studies. Surprisingly, however, a universal staging system and an unambiguous nomenclature for developing lancelets have not yet been adopted by the scientific community. In this work, we characterized the development of the European lancelet () using confocal microscopy and compiled a streamlined developmental staging system, from fertilization through larval life, including an unambiguous stage nomenclature. By tracing growth curves of the European lancelet reared at different temperatures, we were able to show that our staging system permitted an easy conversion of any developmental time into a specific stage name. Furthermore, comparisons of embryos and larvae from the European lancelet (), the Florida lancelet (), two Asian lancelets ( and ), and the Bahamas lancelet () demonstrated that our staging system could readily be applied to other lancelet species. Although the detailed staging description was carried out on developing , the comparisons with other lancelet species thus strongly suggested that both staging and nomenclature are applicable to all extant lancelets. We conclude that this description of embryonic and larval development will be of great use for the scientific community and that it should be adopted as the new standard for defining and naming developing lancelets. More generally, we anticipate that this work will facilitate future studies comparing representatives from different chordate lineages.
PubMed: 34095136
DOI: 10.3389/fcell.2021.668006 -
Frontiers in Plant Science 2018Anther development progresses through 15 distinct developmental stages in wheat, and accurate determination of anther developmental stages is essential in anther and...
Anther development progresses through 15 distinct developmental stages in wheat, and accurate determination of anther developmental stages is essential in anther and pollen studies. A detailed outline of the development of the wheat anther through its entire developmental program, including the 15 distinct morphological stages, is presented. In bread wheat (), anther developmental stages were correlated with five measurements, namely auricle distance, spike length, spikelet length, anther length and anther width. Spike length and auricle distance were shown to be suitable for rapid anther staging within cultivars. Anther length is an accurate measurement in determining anther stages and may be applicable for use between cultivars. Tapetal Programmed Cell Death (PCD) in wheat begins between late tetrad stage (stage 8) and the early young microspore stage (stage 9) of anther development. Tapetal PCD continues until the vacuolate pollen stage (stage 11), at which point the tapetum fully degrades. The timing of tapetal PCD initiation is slightly delayed compared to that in rice, but is two stages earlier than in the model dicot Arabidopsis. The gene, which encodes a transcription factor regulating the timing of tapetal PCD, reaches its peak expression at the onset of tapetal PCD in wheat.
PubMed: 29527219
DOI: 10.3389/fpls.2018.00228 -
MethodsX Jun 2024Fish display diverse reproductive strategies and their gametogenesis is influenced by numerous genetic, physiological and environmental factors. The analysis of 5S rRNA...
Fish display diverse reproductive strategies and their gametogenesis is influenced by numerous genetic, physiological and environmental factors. The analysis of 5S rRNA expression levels in gonads has been proposed as useful method for the molecular identification of the presence of oocytes in fish tissues. The present method provides an easy and unbiased approach to analyse the expression of tRNAs and 5S rRNA in teleost gonads and stablish the presence and developmental stage of oocytes. Total RNA extracted from gonads is analysed through capillary electrophoresis in a Bioanalyzer 2100 (Agilent Technologies) using Small RNA Assays. Electropherograms allow quantifying the concentrations of tRNAs, 5S rRNA and 5.8S rRNA per sample and calculate their tRNA/5.8S rRNA and 5S/5.8S rRNA indices. Both indices clearly differentiate ovaries from testes and can be used to identify testes that present oocytes due to exposure to environmental xenoestrogens. The tRNA/5.8S and 5S/5.8S indices show the highest values in ovaries in previtellogenic stage, values decreasing as they advance towards maturity.•Detailed molecular method to sex fish and quantitatively identify the maturity stage of females.•tRNA levels in gonads can help in the study of teleost reproduction (female fecundity assessment, molecular gonad sexing) and environmental health assessment.
PubMed: 38192358
DOI: 10.1016/j.mex.2023.102526 -
Cold Spring Harbor Protocols Apr 2022is a powerful model system for cell and developmental biology in part because frogs produce thousands of eggs and embryos year-round. In vitro fertilization (IVF) is...
is a powerful model system for cell and developmental biology in part because frogs produce thousands of eggs and embryos year-round. In vitro fertilization (IVF) is ideal for obtaining developmentally synchronized embryos for microinjection or when natural mating has failed to produce a fertilization. In IVF, females are induced to ovulate, and then eggs are collected by manual expression. After testes are collected from a euthanized male frog, the eggs are fertilized in vitro. The embryos are then treated with cysteine to remove the sticky protective jelly coat. Dejellied embryos are much easier to manipulate during microinjection or when sorting in a Petri dish. The jelly coat is also very difficult to penetrate with an injection needle. After microinjection, embryos are maintained in Petri dishes until desired stages are reached. Although in vitro fertilization in and is similar, critical differences in solutions, handling of testis, response of fertilized eggs directly after introduction of sperm, and developmental timing are required for successful fertilization in .
Topics: Animals; Female; Fertilization; Fertilization in Vitro; Male; Spermatozoa; Xenopus; Xenopus laevis
PubMed: 34031212
DOI: 10.1101/pdb.prot106351 -
Methods in Cell Biology 2016As the processes of embryogenesis become increasingly well understood, there is growing interest in the development that occurs at later, postembryonic stages....
As the processes of embryogenesis become increasingly well understood, there is growing interest in the development that occurs at later, postembryonic stages. Postembryonic development holds tremendous potential for discoveries of both fundamental and translational importance. Zebrafish, which are small, rapidly and externally developing, and which boast a wealth of genetic resources, are an outstanding model of vertebrate postembryonic development. Nonetheless, there are specific challenges posed by working with zebrafish at these stages, and this chapter is meant to serve as a primer for those working with larval and juvenile zebrafish. Since accurate staging is critical for high-quality results and experimental reproducibility, we outline best practices for reporting postembryonic developmental progress. Emphasizing the importance of accurate staging, we present new data showing that rates of growth and size-stage relationships can differ even between wild-type strains. Finally, since rapid and uniform development is particularly critical when working at postembryonic stages, we briefly describe methods that we use to achieve high rates of growth and developmental uniformity through postembryonic stages in both wild-type and growth-compromised zebrafish.
Topics: Animals; Embryo, Nonmammalian; Larva; Zebrafish
PubMed: 27312506
DOI: 10.1016/bs.mcb.2015.12.001 -
Scientific Reports Sep 2021Amyotrophic lateral sclerosis is an adult-onset neurodegenerative disorder characterized by loss of motor neurons. Mitochondria are essential for neuronal survival but... (Observational Study)
Observational Study
Amyotrophic lateral sclerosis is an adult-onset neurodegenerative disorder characterized by loss of motor neurons. Mitochondria are essential for neuronal survival but the developmental timing and mechanistic importance of mitochondrial dysfunction in sporadic ALS (sALS) neurons is not fully understood. We used human induced pluripotent stem cells and generated a developmental timeline by differentiating sALS iPSCs to neural progenitors and to motor neurons and comparing mitochondrial parameters with familial ALS (fALS) and control cells at each developmental stage. We report that sALS and fALS motor neurons have elevated reactive oxygen species levels, depolarized mitochondria, impaired oxidative phosphorylation, ATP loss and defective mitochondrial protein import compared with control motor neurons. This phenotype develops with differentiation into motor neurons, the affected cell type in ALS, and does not occur in the parental undifferentiated sALS cells or sALS neural progenitors. Our work demonstrates a developmentally regulated unifying mitochondrial phenotype between patient derived sALS and fALS motor neurons. The occurrence of a unifying mitochondrial phenotype suggests that mitochondrial etiology known to SOD1-fALS may applicable to sALS. Furthermore, our findings suggest that disease-modifying treatments focused on rescue of mitochondrial function may benefit both sALS and fALS patients.
Topics: Amyotrophic Lateral Sclerosis; Biopsy; Cell Differentiation; Cells, Cultured; Fibroblasts; Humans; Induced Pluripotent Stem Cells; Mitochondria; Motor Neurons; Neural Stem Cells; Primary Cell Culture; Reactive Oxygen Species; Skin
PubMed: 34556702
DOI: 10.1038/s41598-021-97928-7 -
The Journal of Craniofacial SurgeryCleft lip and palate (CLP) repair is typically performed in a staged fashion, which requires multiple instances of anesthetic exposure during a critical period of infant...
Cleft lip and palate (CLP) repair is typically performed in a staged fashion, which requires multiple instances of anesthetic exposure during a critical period of infant neurodevelopment. One solution to this concern includes the implementation of a single-stage CLP repair performed between 6 and 12 months of age. This study aimed to compare total anesthetic exposure between single-stage and staged CLP repairs. A retrospective review of unilateral CLP repairs between 2013 and 2018 conducted at a single institution was performed. Patients underwent either traditional, staged lip and palate repair, or single-stage complete cleft repair, where palate, lip, alveolus, and nasal repair was performed simultaneously. Primary endpoints included: total surgical time and total anesthetic exposure. Secondary endpoints included: excess anesthesia time, recovery room time, length of stay, and type of anesthetic administered. Two hundred twenty-five (n = 225) unilateral CLP repairs were conducted at the Loma Linda University. Detailed anesthetic data for eighty-six (n = 86) single-stage and twenty-eight (n = 28) staged operations were available. There was a statistically significant decrease in anesthetic exposure in single-stage versus staged repairs (316 minutes versus 345 minutes, P = 0.017), despite similar procedure times (260 minutes versus 246 minutes, P = 0.224). This resulted in near double excess anesthetic exposure time in the staged group (98 minutes versus 56 minutes, P < 0.001), primarily occurring during induction. This analysis suggests that single-stage CLP repair can reduce wasted time under general anesthesia and potentially reduce harmful neuronal toxicity in the developmental period in this at-risk population.
Topics: Anesthesia, Dental; Anesthetics; Cleft Lip; Cleft Palate; Humans; Infant; Retrospective Studies
PubMed: 33704974
DOI: 10.1097/SCS.0000000000007156 -
Genes Dec 2019Wing dimorphism is considered as an adaptive trait of insects. Brown planthoppers (BPHs) , a serious pest of rice, are either macropterous or brachypterous. Genetic and...
Wing dimorphism is considered as an adaptive trait of insects. Brown planthoppers (BPHs) , a serious pest of rice, are either macropterous or brachypterous. Genetic and environmental factors are both likely to control wing morph determination in BPHs, but the hereditary law and genes network are still unknown. Here, we investigated changes in gene expression levels between macropterous and brachypterous BPHs by creating artificially bred morphotype lines. The nearly pure-bred strains of macropterous and brachypterous BPHs were established, and their transcriptomes and gene expression levels were compared. Over ten-thousand differentially expressed genes (DEGs) between macropterous and brachypterous strains were found in the egg, nymph, and adult stages, and the three stages shared 6523 DEGs. The regulation of actin cytoskeleton, focal adhesion, tight junction, and adherens junction pathways were consistently enriched with DEGs across the three stages, whereas insulin signaling pathway, metabolic pathways, vascular smooth muscle contraction, platelet activation, oxytocin signaling pathway, sugar metabolism, and glycolysis/gluconeogenesis were significantly enriched by DEGs in a specific stage. Gene expression trend profiles across three stages were different between the two strains. Eggs, nymphs, and adults from the macropterous strain were distinguishable from the brachypterous based on gene expression levels, and genes that were related to wing morphs were differentially expressed between wing strains or strain × stage. A proposed mode based on genes and environments to modulate the wing dimorphism of BPHs was provided.
Topics: Amino Acid Sequence; Animals; Gene Expression; Gene Expression Profiling; Gene Expression Regulation, Developmental; Hemiptera; Phylogeny; Transcriptome; Wings, Animal
PubMed: 31878073
DOI: 10.3390/genes11010019 -
BMC Zoology Jul 2022Body size is a fundamental organismal trait. However, as body size and ecological contexts change across developmental time, evolutionary divergence may cause unexpected...
BACKGROUND
Body size is a fundamental organismal trait. However, as body size and ecological contexts change across developmental time, evolutionary divergence may cause unexpected patterns of body size diversity among developmental stages. This may be particularly evident in polyphenic developmental stages specialized for dispersal. The dauer larva is such a stage in nematodes, and Caenorhabditis species disperse by traveling on invertebrate carriers. Here, we describe the morphology of a stress-resistant, dauer-like larval stage of the nematode Caenorhabditis inopinata, whose adults can grow to be nearly twice as long as its close relative, the model organism C. elegans.
RESULTS
We find that a dauer-like, stress-resistant larval stage in two isolates of C. inopinata is on average 13% shorter and 30% wider than the dauer larvae of C. elegans, despite its much longer adult stage. Additionally, many C. inopinata dauer-like larvae were ensheathed, a possible novelty in this lineage reminiscent of the infective juveniles of parasitic nematodes. Variation in dauer-like larva formation frequency among twenty-four wild isolates of C. inopinata was also observed, although frequencies were low across all isolates (< 2%), with many isolates unable to produce dauer-like larvae under conventional laboratory conditions.
CONCLUSION
Most Caenorhabditis species thrive on rotting plants and disperse on snails, slugs, or isopods (among others) whereas C. inopinata is ecologically divergent and thrives in fresh Ficus septica figs and disperses on their pollinating wasps. While there is some unknown factor of the fig environment that promotes elongated body size in C. inopinata adults, the small size or unique life history of its fig wasp carrier may be driving the divergent morphology of its stress-resistant larval stages. Further characterization of the behavior, development, and morphology of this stage will refine connections to homologous developmental stages in other species and determine whether ecological divergence across multiple developmental stages can promote unexpected and opposing changes in body size dimensions within a single species.
PubMed: 37170380
DOI: 10.1186/s40850-022-00131-y -
Heredity Oct 2019Environments often vary across a life cycle, imposing fluctuating natural selection across development. Such fluctuating selection can favor different phenotypes in...
Environments often vary across a life cycle, imposing fluctuating natural selection across development. Such fluctuating selection can favor different phenotypes in different life stages, but stage-specific evolutionary responses will depend on genetic variance, covariance, and their interaction across development and across environments. Thus, quantifying how genetic architecture varies with plastic responses to the environment and across development is vital to predict whether stage-specific adaptation will occur in nature. Additionally, the interaction of genetic variation and environmental plasticity (GxE) may be stage-specific, leading to a three-way interaction between genotype, environment, and development or GxDxE. To test for these patterns, we exposed larvae and adults of Drosophila melanogaster isogenic lines derived from a natural population to extreme heat and cold stress after developmental acclimation to cool (18 °C) and warm (25 °C) conditions and measured genetic variance for thermal hardiness. We detected significant GxE that was specific to larvae and adults for cold and heat hardiness (GxDxE), but no significant genetic correlation across development for either trait at either acclimation temperature. However, cross-development phenotypic correlations for acclimation responses suggest that plasticity itself may be developmentally constrained, though rigorously testing this hypothesis requires more experimentation. These results illustrate the potential for stage-specific adaptation within a complex life cycle and demonstrate the importance of measuring traits at appropriate developmental stages and environmental conditions when predicting evolutionary responses to changing climates.
Topics: Adaptation, Physiological; Animals; Climate Change; Cold Temperature; Drosophila melanogaster; Gene-Environment Interaction; Genetic Variation; Genotype; Hot Temperature; Larva; Life Cycle Stages; Selection, Genetic; Temperature
PubMed: 31164731
DOI: 10.1038/s41437-019-0236-9