scholarly journals Walter Jakob Gehring. 20 March 1939—29 May 2014

2021 ◽  
Author(s):  
Ginés Morata ForMemRS ◽  
Markus Affolter
Keyword(s):  
Molecular Mechanisms ◽  
Gifted Students ◽  
Fruit Fly ◽  
Football Player ◽  
Molecular Techniques ◽  
General Interest ◽  
Animal Development ◽  
Developmental Problems ◽  
Scientific Disciplines ◽  
Great Energy

Walter Jakob Gehring was one of the most influential developmental biologists of the last 50 years. First as a student with Professor Ernst Hadorn in Zurich, later as a postdoc in Yale and finally as group leader in Basel, he was involved in a number of major discoveries that had a profound impact in the understanding of the genetic and molecular mechanisms of animal development, not only for the fruit fly Drosophila but for the whole animal kingdom. Throughout his career Gehring demonstrated an outstanding ability to recognize key problems and then to push experimental work on these problems with great energy. Gehring pioneered the application of molecular techniques to developmental problems, an approach that was at the root of many of his contributions. His laboratory was involved in a number of key findings: the first cloning of a Hox gene, the discovery of the homeobox, the enhancer trap method, and the remarkable conservation of features of the visual system in metazoans. He was an excellent speaker, with special ability to emphasize the relevant aspects of his work and to draw conclusions of general interest. This attracted a number of gifted students and postdocs who were key for the success of his research group. Passionately interested in science, he was also very excited about other scientific disciplines; he was an accomplished bird watcher and was also fascinated by marine life. But he also had non-scientific interests, too; he claimed to be an excellent football player and frequently commented that he had had to decide whether to be a scientist or a professional footballer. He decided on the former, but one wonders if he might have been a Swiss version of Messi or Ronaldo.

The development of the human uterus: morphogenesis to menarche

2020 ◽  
Vol 27 (1) ◽  
pp. 1-26
Author(s):  
Marwan Habiba ◽  
Rosemarie Heyn ◽  
Paola Bianchi ◽  
Ivo Brosens ◽  
Giuseppe Benagiano
Keyword(s):  
Molecular Mechanisms ◽  
Uterine Bleeding ◽  
Molecular Techniques ◽  
Receptor Expression ◽  
Abnormal Development ◽  
Uterine Disease ◽  
Adult Onset ◽  
Uterine Anomalies ◽  
Mullerian Ducts ◽  
Uterine Development

ABSTRACT There is emerging evidence that early uterine development in humans is an important determinant of conditions such as ontogenetic progesterone resistance, menstrual preconditioning, defective deep placentation and pre-eclampsia in young adolescents. A key observation is the relative infrequency of neonatal uterine bleeding and hormone withdrawal at birth. The origin of the uterus from the fusion of the two paramesonephric, or Müllerian, ducts was described almost 200 years ago. The uterus forms around the 10th week of foetal life. The uterine corpus and the cervix react differently to the circulating steroid hormones during pregnancy. Adult uterine proportions are not attained until after puberty. It is unclear if the endometrial microbiome and immune response—which are areas of growing interest in the adult—play a role in the early stages of uterine development. The aim is to review the phases of uterine development up until the onset of puberty in order to trace the origin of abnormal development and to assess current knowledge for features that may be linked to conditions encountered later in life. The narrative review incorporates literature searches of Medline, PubMed and Scopus using the broad terms individually and then in combination: uterus, development, anatomy, microscopy, embryology, foetus, (pre)-puberty, menarche, microbiome and immune cells. Identified articles were assessed manually for relevance, any linked articles and historical textbooks. We included some animal studies of molecular mechanisms. There are competing theories about the contributions of the Müllerian and Wolffian ducts to the developing uterus. Endometrium features are suggestive of an oestrogen effect at 16–20 weeks gestation. The discrepancy in the reported expression of oestrogen receptor is likely to be related to the higher sensitivity of more recent techniques. Primitive endometrial glands appear around 20 weeks. Features of progestogen action are expressed late in the third trimester. Interestingly, progesterone receptor expression is higher at mid-gestation than at birth when features of endometrial maturation are rare. Neonatal uterine bleeding occurs in around 5% of neonates. Myometrial differentiation progresses from the mesenchyme surrounding the endometrium at the level of the cervix. During infancy, the uterus and endometrium remain inactive. The beginning of uterine growth precedes the onset of puberty and continues for several years after menarche. Uterine anomalies may result from fusion defects or atresia of one or both Müllerian ducts. Organogenetic differentiation of Müllerian epithelium to form the endometrial and endocervical epithelium may be independent of circulating steroids. A number of genes have been identified that are involved in endometrial and myometrial differentiation although gene mutations have not been demonstrated to be common in cases of uterine malformation. The role, if any, of the microbiome in relation to uterine development remains speculative. Modern molecular techniques applied to rodent models have enhanced our understanding of uterine molecular mechanisms and their interactions. However, little is known about functional correlates or features with relevance to adult onset of uterine disease in humans. Prepubertal growth and development lends itself to non-invasive diagnostics such as ultrasound and MRI. Increased awareness of the occurrence of neonatal uterine bleeding and of the potential impact on adult onset disease may stimulate renewed research in this area.

scholarly journals Transcriptome characterization analysis and molecular profiles of obligatory diapause induction of the Chinese citrus fruit fly,Bactrocera minax(Diptera: Tephritidae)

2019 ◽  
Author(s):  
Zhixiong Zhou ◽  
Xiaolin Dong ◽  
Chuanren Li
Keyword(s):  
Signaling Pathway ◽  
Molecular Mechanisms ◽  
Expression Patterns ◽  
Citrus Fruit ◽  
Pupal Stage ◽  
Fruit Fly ◽  
Diapause Induction ◽  
Regulation Mechanism ◽  
Pupal Diapause ◽  
Specific Stage

AbstractThe Chinese citrus fruit fly,Bactrocera minax, is a devastating citrus pest in China, Bhutan and India. It will enter obligatory pupal diapause in each generation at specific stage, while little is known about the course and the molecular mechanisms of diapause induction. To gain insight into possible mechanisms of obligatory pupal diapause induction, high-throughput RNA-seq data were generated from second-instar larvae (2L), third-instar larvae (3L) and pupal (P, one week after pupating). A total of 116,402 unigenes were assembled and researched against public databases, and 54,781 unigenes matched to proteins in the NCBI database using the BLAST search. Three pairwise comparisons were performed, and significantly differentially regulated transcripts were identified. Several differentially expressed genes (DEGs) expression patterns revealed that those highly or lowly expressed genes in pupal stage were predicted to be involved in diapause induction. Moreover, GO function and KEGG pathway analysis were performed on all DEGs and showed that 20-hydroxyecdysone (20E) biosynthesis, insulin signaling pathway, FoxO signaling pathway, cell cycle and metabolism pathway may be related to the obligatory diapause of the Chinese citrus fruit fly. This study provides valuable information about the Chinese citrus fruit fly transcriptome for future gene function research, and contributes to the in-depth elucidation of the molecular regulation mechanism of insect obligatory diapause induction.

scholarly journals The Making of Long-Lasting Memories: A Fruit Fly Perspective

2021 ◽  
Vol 15 ◽  
Author(s):  
Camilla Roselli ◽  
Mani Ramaswami ◽  
Tamara Boto ◽  
Isaac Cervantes-Sandoval
Keyword(s):  
Learning And Memory ◽  
Neural Activity ◽  
Molecular Mechanisms ◽  
De Novo ◽  
Fruit Fly ◽  
Memory Formation ◽  
Synaptic Activity ◽  
Model Organisms ◽  
Transient Wave ◽  
Control Of Gene Expression

Understanding the nature of the molecular mechanisms underlying memory formation, consolidation, and forgetting are some of the fascinating questions in modern neuroscience. The encoding, stabilization and elimination of memories, rely on the structural reorganization of synapses. These changes will enable the facilitation or depression of neural activity in response to the acquisition of new information. In other words, these changes affect the weight of specific nodes within a neural network. We know that these plastic reorganizations require de novo protein synthesis in the context of Long-term memory (LTM). This process depends on neural activity triggered by the learned experience. The use of model organisms like Drosophila melanogaster has been proven essential for advancing our knowledge in the field of neuroscience. Flies offer an optimal combination of a more straightforward nervous system, composed of a limited number of cells, and while still displaying complex behaviors. Studies in Drosophila neuroscience, which expanded over several decades, have been critical for understanding the cellular and molecular mechanisms leading to the synaptic and behavioral plasticity occurring in the context of learning and memory. This is possible thanks to sophisticated technical approaches that enable precise control of gene expression in the fruit fly as well as neural manipulation, like chemogenetics, thermogenetics, or optogenetics. The search for the identity of genes expressed as a result of memory acquisition has been an active interest since the origins of behavioral genetics. From screenings of more or less specific candidates to broader studies based on transcriptome analysis, our understanding of the genetic control behind LTM has expanded exponentially in the past years. Here we review recent literature regarding how the formation of memories induces a rapid, extensive and, in many cases, transient wave of transcriptional activity. After a consolidation period, transcriptome changes seem more stable and likely represent the synthesis of new proteins. The complexity of the circuitry involved in memory formation and consolidation is such that there are localized changes in neural activity, both regarding temporal dynamics and the nature of neurons and subcellular locations affected, hence inducing specific temporal and localized changes in protein expression. Different types of neurons are recruited at different times into memory traces. In LTM, the synthesis of new proteins is required in specific subsets of cells. This de novo translation can take place in the somatic cytoplasm and/or locally in distinct zones of compartmentalized synaptic activity, depending on the nature of the proteins and the plasticity-inducing processes that occur. We will also review recent advances in understanding how localized changes are confined to the relevant synapse. These recent studies have led to exciting discoveries regarding proteins that were not previously involved in learning and memory processes. This invaluable information will lead to future functional studies on the roles that hundreds of new molecular actors play in modulating neural activity.

scholarly journals Multilevel regulation of the glass locus during Drosophila eye development

2019 ◽  
Author(s):  
Cornelia Fritsch ◽  
F. Javier Bernardo-Garcia ◽  
Tim-Henning Humberg ◽  
Sara Miellet ◽  
Silvia Almeida ◽  
...  
Keyword(s):  
Cell Fate ◽  
Molecular Mechanisms ◽  
Eye Development ◽  
Fruit Fly ◽  
Protein Isoforms ◽  
Critical Feature ◽  
Reading Frame ◽  
Cis Acting ◽  
Temporal Gene Expression ◽  
And Function

ABSTRACTDevelopment of eye tissue is initiated by a conserved set of transcripton factors termed retinal determination network (RDN). In the fruit fly Drosophila melanogaster, the zinc-finger transcription factor Glass acts directly downstream of the RDN to control idendity of photoreceptor as well as non-photoreceptors cells. Tight control of spatial and temporal gene expression is a critical feature during development, cell-fate determination as well as maintainance of differentiated tissues. The molecular mechanisms that control expression of glass, however remain largely unknown. We here identify complex regulatory mechanisms controlling expression of the glass locus. All information to recapitulate glass expression are contained in a compact 5.2 kb cis-acting genomic element by combining different cell-type specific and general enhancers with repressor elements. Moreover, the immature RNA of the locus contains an alterantive small open reading frame (smORF) upstream of the actual glass translation start, resulting in a small peptide instead of the three possible glass protein isoforms. CRISPR/Cas9-based mutagenesis shows that the smORF is not required for the formation of functioning photoreceptors, but to attenuate effects of glass misexpression. Furthermore, editing the genome to generate glass loci eliminating either one or two isoforms shows that only one of the three proteins is critical for formation of functioning photoreceptors, while removing the two other isoforms did not cause defects in developmental or photoreceptor function. Our results show that eye development and function is surprisingly robust and appears buffered to targeted manipulations of critical features of the glass transcript, suggesting a strong selection pressure to allow the formation of a functioning eye.

Protective and Destructive Immunity in the Periodontium: Part 2—T-cell-mediated Immunity in the Periodontium

2006 ◽  
Vol 85 (3) ◽  
pp. 209-219 ◽  
Author(s):  
Y.-T.A. Teng
Keyword(s):  
T Cell ◽  
Porphyromonas Gingivalis ◽  
Virulence Factors ◽  
Molecular Mechanisms ◽  
Molecular Techniques ◽  
Actinobacillus Actinomycetemcomitans ◽  
Antigenic Determinants ◽  
Cell Mediated Immunity ◽  
Receptor Activator ◽  
Molecular Patterns

Based on the results of recent research in the field and Part 1 of this article (in this issue), the present paper will discuss the protective and destructive aspects of the T-cell-mediated adaptive immunity associated with the bacterial virulent factors or antigenic determinants during periodontal pathogenesis. Attention will be focused on: (i) osteoimmunology and periodontal disease; (ii) some molecular techniques developed and applied to identify critical microbial virulence factors or antigens associated with host immunity (with Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis as the model species); and (iii) summarizing the identified virulence factors/antigens associated with periodontal immunity. Thus, further understanding of the molecular mechanisms of the host’s T-cell-mediated immune responses and the critical microbial antigens related to disease pathogenesis will facilitate the development of novel therapeutics or protocols for future periodontal treatments. Abbreviations used in the paper are as follows: A. actinomycetemcomitans ( Aa), Actinobacillus actinomycetemcomitans; Ab, antibody; DC, dendritic cells; mAb, monoclonal antibody; pAb, polyclonal antibody; OC, osteoclast; PAMP, pathogen-associated molecular patterns; P. gingivalis ( Pg), Porphyromonas gingivalis; RANK, receptor activator of NF-κB; RANKL, receptor activator of NF-κB ligand; OPG, osteoprotegerin; TCR, T-cell-receptors; TLR, Toll-like receptors.

The microtubule motor cytoplasmic dynein is required for spindle orientation during germline cell divisions and oocyte differentiation in Drosophila

Development ◽  
1997 ◽  
Vol 124 (12) ◽  
pp. 2409-2419 ◽  
Author(s):  
M. McGrail ◽  
T.S. Hays
Keyword(s):  
Asymmetric Cell Division ◽  
Fruit Fly ◽  
Cytoplasmic Dynein ◽  
Spindle Orientation ◽  
Chain Gene ◽  
Animal Development ◽  
Dynein Motor ◽  
Microtubule Motor ◽  
Two Stages ◽  
Oocyte Differentiation

During animal development cellular differentiation is often preceded by an asymmetric cell division whose polarity is determined by the orientation of the mitotic spindle. In the fruit fly, Drosophila melanogaster, the oocyte differentiates in a 16-cell syncytium that arises from a cystoblast which undergoes 4 synchronous divisions with incomplete cytokinesis. During these divisions, spindle orientation is highly ordered and is thought to impart a polarity to the cyst that is necessary for the subsequent differentiation of the oocyte. Using mutations in the Drosophila cytoplasmic dynein heavy chain gene, Dhc64C, we show that cytoplasmic dynein is required at two stages of oogenesis. Early in oogenesis, dynein mutations disrupt spindle orientation in dividing cysts and block oocyte determination. The localization of dynein in mitotic cysts suggests spindle orientation is mediated by the microtubule motor cytoplasmic dynein. Later in oogenesis, dynein function is necessary for proper differentiation, but does not appear to participate in morphogen localization within the oocyte. These results provide evidence for a novel developmental role for the cytoplasmic dynein motor in cellular determination and differentiation.

scholarly journals The AMPK-PP2A axis in insect fat body is activated by 20-hydroxyecdysone to antagonize insulin/IGF signaling and restrict growth rate

2020 ◽  
Vol 117 (17) ◽  
pp. 9292-9301 ◽  
Author(s):  
Dongwei Yuan ◽  
Shun Zhou ◽  
Suning Liu ◽  
Kang Li ◽  
Haigang Zhao ◽  
...  
Keyword(s):  
Growth Rate ◽  
Protein Kinase ◽  
Energy Homeostasis ◽  
Molecular Mechanisms ◽  
Fat Body ◽  
Larval Growth ◽  
Growth Period ◽  
Fruit Fly ◽  
Growth Factor Signaling ◽  
Phosphatase 2A

In insects, 20-hydroxyecdysone (20E) limits the growth period by triggering developmental transitions; 20E also modulates the growth rate by antagonizing insulin/insulin-like growth factor signaling (IIS). Previous work has shown that 20E cross-talks with IIS, but the underlying molecular mechanisms are not fully understood. Here we found that, in both the silkworm Bombyx mori and the fruit fly Drosophila melanogaster, 20E antagonized IIS through the AMP-activated protein kinase (AMPK)-protein phosphatase 2A (PP2A) axis in the fat body and suppressed the growth rate. During Bombyx larval molt or Drosophila pupariation, high levels of 20E activate AMPK, a molecular sensor that maintains energy homeostasis in the insect fat body. In turn, AMPK activates PP2A, which further dephosphorylates insulin receptor and protein kinase B (AKT), thus inhibiting IIS. Activation of the AMPK-PP2A axis and inhibition of IIS in the Drosophila fat body reduced food consumption, resulting in the restriction of growth rate and body weight. Overall, our study revealed an important mechanism by which 20E antagonizes IIS in the insect fat body to restrict the larval growth rate, thereby expanding our understanding of the comprehensive regulatory mechanisms of final body size in animals.

ANTI-EPILEPTIC DRUGS AND BRAIN AND BEHAVIOURAL DEVELOPMENT IN ANIMAL MODELS AND HUMANS

2010 ◽  
Vol 21 (4) ◽  
pp. 283-306
Author(s):  
NAGHME ADAB ◽  
MICHAEL F O'DONOGHUE
Keyword(s):  
Animal Models ◽  
Animal Studies ◽  
Molecular Mechanisms ◽  
Developmental Problems ◽  
Gestational Exposure ◽  
Behavioural Effects ◽  
Confounding Variables ◽  
Long Time ◽  
Behavioural Repertoire ◽  
Rule Out

Women with epilepsy constitute about 0.6% of pregnancies. The potential for major structural malformations following gestational exposure to anti-epileptic drugs (AEDs) is well known and causes concern as how best to manage epilepsy during pregnancy. In this review we focus on the structural and functional effects on the developing brain to complement other recent reviews. We do not cover neural tube defects which have been reviewed elsewhere. Suffice to say that carbamazepine, lamotrigine and, in particular, valproate exposure are associated with them. We discuss studies based on animal models as well as those that have followed-up children exposed to AEDs in-utero. Careful longitudinal human research can document the cognitive and behavioural effects, but the long time scales required and inability to rule out confounding variables, both genetic and environmental, are serious limitations. Animal studies are based on the assumption that many developmental processes are conserved between the animals used in the models (most often rodents) and humans. However, the hugely expanded cortex and cognitive and behavioural repertoire of humans implies that there are aspects that can not be well modelled. In addition, due to differences in how susceptible different species are to various teratogens, studies always need to be done in man as well. Nevertheless, an understanding of the molecular mechanisms of neuro-teratogenesis derived from animal models will help us predict which anti-epileptic drugs are likely to cause fewer neuro-developmental problems in humans.

scholarly journals Sleep regulates the glial engulfment receptor Draper to promote Wallerian degeneration

2019 ◽  
Author(s):  
Bethany A. Stahl ◽  
James B. Jaggard ◽  
Alex C. Keene
Keyword(s):  
Sleep Deprivation ◽  
Brain Function ◽  
Wallerian Degeneration ◽  
Molecular Mechanisms ◽  
Critical Role ◽  
Fruit Fly ◽  
Glial Activation ◽  
List Type ◽  
Toxic Substances ◽  
Activation Markers

SummarySleep, a universal behavior, is critical for diverse aspects of brain function. Chronic sleep disturbance is associated with numerous health consequences, including neurodegenerative disease and cognitive decline. Neurite damage due to apoptosis, trauma, or genetic factors is a common feature of aging, and clearance of damaged neurons is essential for maintenance of brain function. In the central nervous system, damaged neurites are cleared by Wallerian degeneration, in which activated microglia and macrophages engulf damaged neurons. The fruit fly Drosophila melanogaster provides a powerful model for investigating the relationship between sleep and Wallerian degeneration. Several lines of evidence suggest that glia influence sleep duration, sleep-mediated neuronal homeostasis, and clearance of toxic substances during sleep, raising the possibility that glial engulfment of damaged axons is regulated by sleep. To explore this possibility, we axotomized olfactory receptor neurons and measured the effects of sleep loss or gain on the clearance of damaged neurites. Mechanical sleep deprivation impaired the clearance of damaged neurites, whereas the sleep-promoting drug gaboxadol accelerated clearance. In sleep-deprived animals, multiple markers of glial activation were delayed, including activation of the JAK/STAT pathway, upregulation of the cell corpse engulfment receptor Draper, and innervation of the antennal lobe by glial membranes. These markers were all enhanced when sleep was induced in gaboxadol-treated flies. Taken together, these findings reveal a critical role for sleep in regulation glial activation and engulfment following axotomy, providing a platform for further investigations of the molecular mechanisms underlying sleep-dependent modulation of glial function and neurite clearance.HighlightsSleep deprivation impairs Wallerian degeneration in fruit flies.Pharmacological induction of sleep accelerates Wallerian degeneration.Sleep promotes innervation surrounding damaged neurites by phagocytic glia.Sleep increases levels of the glial activation markers Draper and Stat92E.

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