scholarly journals The dynamic transmission of positional information in stau- mutants during Drosophila embryogenesis

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Zhe Yang ◽  
Hongcun Zhu ◽  
Kakit Kong ◽  
Xiaoxuan Wu ◽  
Jiayi Chen ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Time Windows ◽  
Positional Information ◽  
Intensity Noise ◽  
Wild Type ◽  
Drosophila Embryogenesis ◽  
Self Organized ◽  
Short Time ◽  
Embryo Length ◽  
Drosophila Embryos

It has been suggested that Staufen (Stau) is key in controlling the variability of the posterior boundary of the Hb anterior domain (xHb). However, the mechanism that underlies this control is elusive. Here, we quantified the dynamic 3D expression of segmentation genes in Drosophila embryos. With improved control of measurement errors, we show that the xHb of stau– mutants reproducibly moves posteriorly by 10% of the embryo length (EL) to the wild type (WT) position in the nuclear cycle (nc) 14, and that its variability over short time windows is comparable to that of the WT. Moreover, for stau– mutants, the upstream Bicoid (Bcd) gradients show equivalent relative intensity noise to that of the WT in nc12–nc14, and the downstream Even-skipped (Eve) and cephalic furrow (CF) show the same positional errors as these factors in WT. Our results indicate that threshold-dependent activation and self-organized filtering are not mutually exclusive and could both be implemented in early Drosophila embryogenesis.

scholarly journals The dynamic transmission of positional information in stau- mutants during Drosophila embryogenesis

2019 ◽  
Author(s):  
Zhe Yang ◽  
Hongcun Zhu ◽  
KaKit Kong ◽  
Jiayi Chen ◽  
Xiaxuan Wu ◽  
...  
Keyword(s):  
Measurement Errors ◽  
Positional Information ◽  
Underlying Mechanism ◽  
Dynamic Changes ◽  
Large Shift ◽  
Large Variability ◽  
Self Organized ◽  
Developmental Patterning ◽  
And Shifts ◽  
Embryo Length

AbstractIntriguingly, the developmental patterning during Drosophila embryogenesis is highly accurate and robust despite its dynamic changes and constant fluctuations. It has been suggested that Staufen (Stau) is key in controlling the boundary variability of the gap protein Hunchback (Hb). However, its underlying mechanism is still elusive. Here, we have developed methods to quantify the dynamic 3D expression of segmentation genes in Drosophila embryos. With improved control of measurement errors, our results reveal that the posterior boundary of the Hb anterior domain (xHb) of stau- mutants shows comparable variability to that of the wild type (WT) and shifts posteriorly by nearly 12% of the embryo length (EL) to the WT position in the nuclear cycle (nc) 14. This observed large shift might contribute significantly to the apparent large variability of xHb in previous studies. Moreover, for stau- mutants, the upstream Bicoid (Bcd) gradients show equivalent gradient noise to that of the WT in nc12-nc14, and the downstream Even-skipped (Eve) and cephalic furrow (CF) show the same positional errors as the WT. Our results indicate that threshold-dependent activation and self-organized filtering are not mutually exclusive but could both be implemented in early Drosophila embryogenesis.

Apoptosis of the midline glia during Drosophila embryogenesis: a correlation with axon contact

Development ◽  
1995 ◽  
Vol 121 (2) ◽  
pp. 569-578 ◽  
Author(s):  
M.J. Sonnenfeld ◽  
J.R. Jacobs
Keyword(s):  
Cell Death ◽  
Nerve Cord ◽  
Time Course ◽  
Ventral Nerve Cord ◽  
Ectopic Expression ◽  
Wild Type ◽  
Drosophila Embryogenesis ◽  
Quantitative Studies ◽  
The Central Nervous System ◽  
Drosophila Embryos

We have examined cell death within lineages in the midline of Drosophila embryos. Approximately 50% of cells within the anterior, middle and posterior midline glial (MGA, MGM and MGP) lineages died by apoptosis after separation of the commissural axon tracts. Glial apoptosis is blocked in embryos deficient for reaper, where greater than wild-type numbers of midline glia (MG) are present after stage 12. Quantitative studies revealed that MG death followed a consistent temporal pattern during embryogenesis. Apoptotic MG were expelled from the central nervous system and were subsequently engulfed by phagocytic haemocytes. MGA and MGM survival was apparently dependent upon proper axonal contact. In embryos mutant for the commissureless gene, a decrease in axon-glia contact correlated with a decrease in MGA and MGM survival and accelerated the time course of MG death. In embryos mutant for the slit gene, MGA and MGM maintained contact with longitudinally and contralaterally projecting axons and MG survival was comparable to that in wild-type embryos. The initial number of MG within individual ventral nerve cord segments was increased by ectopic expression of the rhomboid gene, without changing axon number. Extra MGA and MGM were eliminated from the ventral nerve cord by apoptosis to restore wild-type numbers of midline glia. Ectopic rhomboid expression also shifted MGA and MGM cell death to an earlier stage of embryogenesis. One possible explanation is that axon-glia contact or communication promotes survival of the MG and that MG death may result from a competition for available axon contact.

scholarly journals Expression Level of Mature miR172 in Wild Type and StSUT4-Silenced Plants of Solanum tuberosum Is Sucrose-Dependent

2021 ◽  
Vol 22 (3) ◽  
pp. 1455
Author(s):  
Varsha Garg ◽  
Aleksandra Hackel ◽  
Christina Kühn
Keyword(s):  
Solanum Tuberosum ◽  
Wild Type ◽  
Potato Plants ◽  
Mature Leaves ◽  
In Vitro Plantlets ◽  
Long Time ◽  
Short Time ◽  
Cut Leaves

In potato plants, the phloem-mobile miR172 is involved in the sugar-dependent transmission of flower and tuber inducing signal transduction pathways and a clear link between solute transport and the induction of flowering and tuberization was demonstrated. The sucrose transporter StSUT4 seems to play an important role in the photoperiod-dependent triggering of both developmental processes, flowering and tuberization, and the phenotype of StSUT4-inhibited potato plants is reminiscent to miR172 overexpressing plants. The first aim of this study was the determination of the level of miR172 in sink and source leaves of StSUT4-silenced as well as StSUT4-overexpressing plants in comparison to Solanum tuberosum ssp. Andigena wild type plants. The second aim was to investigate the effect of sugars on the level of miRNA172 in whole cut leaves, as well as in whole in vitro plantlets that were supplemented with exogenous sugars. Experiments clearly show a sucrose-dependent induction of the level of mature miR172 in short time as well as long time experiments. A sucrose-dependent accumulation of miR172 was also measured in mature leaves of StSUT4-silenced plants where sucrose export is delayed and sucrose accumulates at the end of the light period.

scholarly journals Self-Organized Nuclear Positioning Synchronizes the Cell Cycle in Drosophila Embryos

Cell ◽  
2019 ◽  
Vol 177 (4) ◽  
pp. 925-941.e17 ◽  
Author(s):  
Victoria E. Deneke ◽  
Alberto Puliafito ◽  
Daniel Krueger ◽  
Avaneesh V. Narla ◽  
Alessandro De Simone ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Nuclear Positioning ◽  
Self Organized ◽  
Drosophila Embryos

scholarly journals NtRNF217, Encoding a Putative RBR E3 Ligase Protein of Nicotiana tabacum, Plays an Important Role in the Regulation of Resistance to Ralstonia solanacearum Infection

2021 ◽  
Vol 22 (11) ◽  
pp. 5507
Author(s):  
Ying Liu ◽  
Yuanman Tang ◽  
Xi Tan ◽  
Wei Ding
Keyword(s):  
Nicotiana Tabacum ◽  
Ralstonia Solanacearum ◽  
Plant Immunity ◽  
E3 Ligase ◽  
Marker Genes ◽  
Susceptible Cultivar ◽  
Wild Type ◽  
Disease Symptoms ◽  
Short Time ◽  
Resistance To Ralstonia Solanacearum

E3 ubiquitin ligases, the most important part of the ubiquitination process, participate in various processes of plant immune response. RBR E3 ligase is one of the E3 family members, but its functions in plant immunity are still little known. NtRNF217 is a RBR E3 ligase in tobacco based on the sequence analysis. To assess roles of NtRNF217 in tobacco responding to Ralstonia solanacearum, overexpression experiments in Nicotiana tabacum (Yunyan 87, a susceptible cultivar) were performed. The results illuminated that NtRNF217-overexpressed tobacco significantly reduced multiplication of R. solanacearum and inhibited the development of disease symptoms compared with wild-type plants. The accumulation of H2O2 and O2− in NtRNF217-OE plants was significantly higher than that in WT-Yunyan87 plants after pathogen inoculation. The activities of CAT and SOD also increased rapidly in a short time after R. solanacearum inoculation in NtRNF217-OE plants. What is more, overexpression of NtRNF217 enhanced the transcript levels of defense-related marker genes, such as NtEFE26, NtACC Oxidase, NtHIN1, NtHSR201, and NtSOD1 in NtRNF217-OE plants after R. solanacearum inoculation. The results suggested that NtRNF217 played an important role in regulating the expression of defense-related genes and the antioxidant enzymes, which resulted in resistance to R. solanacearum infection.

scholarly journals Self-organized cytoskeletal alignment during Drosophila mesoderm invagination

2020 ◽  
Vol 375 (1809) ◽  
pp. 20190551 ◽  
Author(s):  
Adam C. Martin
Keyword(s):  
Self Organization ◽  
Mechanical Forces ◽  
Feedback Process ◽  
Wild Type ◽  
Tissue Morphogenesis ◽  
Cell Behaviour ◽  
Feedback Mechanisms ◽  
Self Organized ◽  
Actomyosin Cytoskeleton ◽  
Shape Changes

During tissue morphogenesis, mechanical forces are propagated across tissues, resulting in tissue shape changes. These forces in turn can influence cell behaviour, leading to a feedback process that can be described as self-organizing. Here, I discuss cytoskeletal self-organization and point to evidence that suggests its role in directing force during morphogenesis. During Drosophila mesoderm invagination, the shape of the region of cells that initiates constriction creates a mechanical pattern that in turn aligns the cytoskeleton with the axis of greatest resistance to contraction. The wild-type direction of the force controls the shape and orientation of the invaginating mesoderm. Given the ability of the actomyosin cytoskeleton to self-organize, these types of feedback mechanisms are likely to play important roles in a range of different morphogenetic events. This article is part of the discussion meeting issue ‘Contemporary morphogenesis'.

scholarly journals Time-Varying Associations Between an Exposure History and a Subsequent Health Outcome: A landmark Approach to Identify Critical Windows.

2021 ◽  
Author(s):  
Maude Wagner ◽  
Francine Grodstein ◽  
Karen Leffondre ◽  
Cécilia Samieri ◽  
Cécile Proust-Lima
Keyword(s):  
Risk Factors ◽  
Health Outcome ◽  
Measurement Errors ◽  
Mixed Model ◽  
Time Window ◽  
Time Windows ◽  
Critical Time ◽  
Cumulative Exposure ◽  
Exposure Measurement ◽  
Exposure History

Abstract Background: Long-term behavioral and health risk factors constitute a primary focus of research on the etiology of chronic diseases. Yet, identifying critical time-windows during which risk factors have the strongest impact on disease risk is challenging. To assess the trajectory of association of an exposure history with an outcome, the weighted cumulative exposure index (WCIE) has been proposed, with weights reflecting the relative importance of exposures at different times. However, WCIE is restricted to a complete observed error-free exposure whereas exposures are often measured with intermittent missingness and error. Moreover, it rarely explores exposure history that is very distant from the outcome as usually sought in life-course epidemiology.Methods: We extend the WCIE methodology to (i) exposures that are intermittently measured with error, and (ii) contexts where the exposure time-window precedes the outcome time-window using a landmark approach. First, the individual exposure history up to the landmark time is estimated using a mixed model that handles missing data and error in exposure measurement, and the predicted complete error-free exposure history is derived. Then the WCIE methodology is applied to assess the trajectory of association between the predicted exposure history and the health outcome collected after the landmark time. In our context, the health outcome is a longitudinal marker analyzed using a mixed model.Results: A simulation study first demonstrates the correct inference obtained with this approach. Then, applied to the Nurses’ Health Study (19,415 women) to investigate the association between body mass index history (collected from midlife) and subsequent cognitive decline (evaluated after age 70), the method identified two major critical windows of association: long before the first cognitive evaluation (roughly 24 to 12 years), higher levels of BMI were associated with poorer cognition. In contrast, adjusted for the whole history, higher levels of BMI became associated with better cognition in the last years prior to the first cognitive interview, thus reflecting reverse causation (changes in exposure due to underlying disease).Conclusions: This approach, easy to implement, provides a flexible tool for studying complex dynamic relationships and identifying critical time windows while accounting for exposure measurement errors.

scholarly journals Peripheral Administration of RF9 Does Not Affect Hypothalamic-PituitaryGonadal Axis in Normal Fed Adult Male Macaque

2020 ◽  
pp. 1-5
Author(s):  
Aalia Batool ◽  
Madiha Wazir ◽  
Rahim Ullah ◽  
Aalia Batool ◽  
Rabia Naz ◽  
...  
Keyword(s):  
Adult Male ◽  
Normal Saline ◽  
Time Windows ◽  
Treated Group ◽  
Plasma Testosterone ◽  
Control Group ◽  
Hpg Axis ◽  
Testosterone Levels ◽  
Physiological Conditions ◽  
Short Time

Stress represses hypothalamic-pituitary-gonadal axis (HPG-axis) but RF9, a synthetic peptide, rescues such repression. To assess the role of RF9 in regulating HPG-axis under normal physiological conditions in higher primates, RF9 was administered to intact adult male rhesus monkeys and response of the HPG-axis was examined by measuring plasma testosterone as an end parameter of the axis. Control group (n=4) received normal saline whereas the treated group (n=4) received RF9. On the first day of experiment, four bolus injections of normal saline (1ml/animal) were administered intravenously at 2-hr interval to the control monkeys. Similarly, on the second day of experiment, treated group received four iv bolus injections of RF9 (0.1mg/kg BW) at 2-hr interval. Serial blood samples were collected at 20 min interval during a 6-hr period which started just after first saline/RF9 injection. Plasma testosterone levels were measured by using a specific EIA. Overall means of plasma testosterone levels and plasma testosterone area under curve (AUC) and overall mean testosterone and mean testosterone AUC in short time windows following each injection of RF9 and saline were comparable between the groups. Our results demonstrate that RF9 has no role in regulating HPG-axis under normal physiological conditions in adult male monkeys.

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