| 319491. |
- Hench, Jürgen, et al.
(författare)
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Spatio-temporal reference model of Caenorhabditis elegans embryogenesis with cell contact maps
- 2009
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Ingår i: Developmental Biology. - : Elsevier BV. - 0012-1606 .- 1095-564X. ; 333:1, s. 1-13
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Tidskriftsartikel (refereegranskat)abstract
- The nematode Caenorhabditis elegans has been used as a model for developmental biology for decades. Still, the few publicly available spatio-temporal (4D) data sets have conflicting information regarding variability of cell positions and are not well-suited for a standard 4D embryonic model, due to compression. We have recorded six uncompressed embryos, and determined their lineage and 4D coordinates, including nuclear radii, until the end of gastrulation. We find a remarkable degree of stability in the cell positions, as well as little rotational movement, which allowed us to combine the data into a single reference model of C. elegans embryogenesis. Using Voronoi decomposition we generated the list of all predicted cell contacts during early embryogenesis and calculated these contacts up to the similar to 150 cell stage, and find that about 1500 contacts last 2.5 min or longer. The cell contact map allows for comparison of multiple 4D data sets, e. g., mutants or related species, at the cellular level. A comparison of our uncompressed 4D model with a compressed embryo shows that up to 40% of the cell contacts can be different. To visualize the 4D model interactively we developed a software utility. Our model provides an anatomical resource and can serve as foundation to display 4D expression data, a basis for developmental systems biology.
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| 319492. |
- Hench, Jürgen, et al.
(författare)
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The Homeobox Genes of Caenorhabditis elegans and Insights into Their Spatio-Temporal Expression Dynamics during Embryogenesis
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:5
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Tidskriftsartikel (refereegranskat)abstract
- Homeobox genes play crucial roles for the development of multicellular eukaryotes. We have generated a revised list of all homeobox genes for Caenorhabditis elegans and provide a nomenclature for the previously unnamed ones. We show that, out of 103 homeobox genes, 70 are co-orthologous to human homeobox genes. 14 are highly divergent, lacking an obvious ortholog even in other Caenorhabditis species. One of these homeobox genes encodes 12 homeodomains, while three other highly divergent homeobox genes encode a novel type of double homeodomain, termed HOCHOB. To understand how transcription factors regulate cell fate during development, precise spatio-temporal expression data need to be obtained. Using a new imaging framework that we developed, Endrov, we have generated spatio-temporal expression profiles during embryogenesis of over 60 homeobox genes, as well as a number of other developmental control genes using GFP reporters. We used dynamic feedback during recording to automatically adjust the camera exposure time in order to increase the dynamic range beyond the limitations of the camera. We have applied the new framework to examine homeobox gene expression patterns and provide an analysis of these patterns. The methods we developed to analyze and quantify expression data are not only suitable for C. elegans, but can be applied to other model systems or even to tissue culture systems.
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| 319493. |
- Henche, Anna-Lena, et al.
(författare)
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Structure and function of the adhesive type IV pilus of Sulfolobus acidocaldarius
- 2012
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Ingår i: Environmental Microbiology. - : Wiley. - 1462-2912 .- 1462-2920. ; 14:12, s. 3188-3202
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Tidskriftsartikel (refereegranskat)abstract
- Archaea display a variety of type IV pili on their surface and employ them in different physiological functions. In the crenarchaeon Sulfolobus acidocaldarius the most abundant surface structure is the aap pilus (archaeal adhesive pilus). The construction of in frame deletions of the aap genes revealed that all the five genes (aapA, aapX, aapE, aapF, aapB) are indispensible for assembly of the pilus and an impact on surface motility and biofilm formation was observed. Our analyses revealed that there exists a regulatory cross-talk between the expression of aap genes and archaella (formerly archaeal flagella) genes during different growth phases. The structure of the aap pilus is entirely different from the known bacterial type IV pili as well as other archaeal type IV pili. An aap pilus displayed 3 stranded helices where there is a rotation per subunit of ∼ 138° and a rise per subunit of ∼ 5.7 Å. The filaments have a diameter of ∼ 110 Å and the resolution was judged to be ∼ 9 Å. We concluded that small changes in sequence might be amplified by large changes in higher-order packing. Our finding of an extraordinary stability of aap pili possibly represents an adaptation to harsh environments that S. acidocaldarius encounters.
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| 319494. |
- Henckel, Ewa, et al.
(författare)
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A novel association between ykl-40, a marker of structural lung disease, and short telomere length in 10-year-old children with bronchopulmonary dysplasia
- 2021
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Ingår i: Children. - : MDPI. - 2227-9067. ; 8:2
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Tidskriftsartikel (refereegranskat)abstract
- Extremely preterm infants are born with immature lungs and are exposed to an inflammatory environment as a result of oxidative stress. This may lead to airway remodeling, cellular aging and the development of bronchopulmonary dysplasia (BPD). Reliable markers that predict the long-term consequences of BPD in infancy are still lacking. We analyzed two biomarkers of cellular aging and lung function, telomere length and YKL-40, respectively, at 10 years of age in children born preterm with a history of BPD (n = 29). For comparison, these markers were also evaluated in sex-and-age-matched children born at term with childhood asthma (n = 28). Relative telomere length (RTL) was measured in whole blood with qPCR and serum YKL-40 with ELISA, and both were studied in relation to gas exchange and the regional ventilation/perfusion ratio using three-dimensional V/Q-scintigraphy (single photon emission computer tomography, SPECT) in children with BPD. Higher levels of YKL-40 were associated with shorter leukocyte RTL (Pearson’s correlation: −0.55, p = 0.002), but were not associated with a lower degree of matching between ventilation and perfusion within the lung. Serum YKL-40 levels were significantly higher in children with BPD compared to children with asthma (17.7 vs. 13.2 ng/mL, p < 0.01). High levels of YKL-40 and short RTLs were associated to the need for ventilatory support more than 1 month in the neonatal period (p < 0.01). The link between enhanced telomere shortening in childhood and structural remodeling of the lung, as observed in children with former BPD but not in children with asthma at the age of 10 years, suggests altered lung development related to prematurity and early life inflammatory exposure. In conclusion, relative telomere length and YKL-40 may serve as biomarkers of altered lung development as a result of early-life inflammation in children with a history of prematurity.
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| 319495. |
- Henckel, Ewa, et al.
(författare)
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Hematopoietic cellular aging is not accelerated during the first 2 years of life in children born preterm
- 2020
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Ingår i: Pediatric Research. - : Nature Publishing Group. - 0031-3998 .- 1530-0447. ; 88
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Tidskriftsartikel (refereegranskat)abstract
- Background: Prematurity in itself and exposure to neonatal intensive care triggers inflammatory processes and oxidative stress, leading to risk for disease later in life. The effects on cellular aging processes are incompletely understood.Methods: Relative telomere length (RTL) was measured by qPCR in this longitudinal cohort study with blood samples taken at birth and at 2 years of age from 60 children (16 preterm and 44 term). Viral respiratory infections the first year were evaluated. Epigenetic biological DNA methylation (DNAm) age was predicted based on methylation array data in 23 children (11 preterm and 12 term). RTL change/year and DNAm age change/year was compared in preterm and term during the 2 first years of life.Results: Preterm infants had longer telomeres than term born at birth and at 2 years of age, but no difference in telomere attrition rate could be detected. Predicted epigenetic DNAm age was younger in preterm infants, but rate of DNAm aging was similar in both groups.Conclusions: Despite early exposure to risk factors for accelerated cellular aging, children born preterm exhibited preserved telomeres. Stress during the neonatal intensive care period did not reflect accelerated epigenetic DNAm aging. Early-life aging was not explained by preterm birth.Impact: Preterm birth is associated with elevated disease risk later in life. Preterm children often suffer from inflammation early in life. Stress-related telomere erosion during neonatal intensive care has been proposed. Inflammation-accelerated biological aging in preterm is unknown. We find no accelerated aging due to prematurity or infections during the first 2 years of life.
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| 319496. |
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| 319497. |
- Henckel, E., et al.
(författare)
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Telomere length was similar in school-age children with bronchopulmonary dysplasia and allergic asthma
- 2018
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Ingår i: Acta Paediatrica. - : John Wiley & Sons. - 0803-5253 .- 1651-2227. ; 107:8, s. 1395-1401
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Inflammation is a major factor in the pathophysiology of bronchopulmonary dysplasia (BPD), and it contributes to accelerated telomere shortening and cellular ageing. This study aimed to determine its effect on telomere length and lung function in school-aged children born preterm with BPD.Methods: We examined 29 children with BPD, born preterm in Stockholm county 1998-99, along with 28 children with allergic asthma born at term matched for age and gender. At 10 years of age, we measured relative telomere length (RTL) in blood by quantitative polymerase chain reaction, lung function by spirometry and inflammation by fractional exhaled nitric oxide and blood cytokines.Results: RTL was not different in preterm born with BPD compared to term born children with asthma. The gender effect was strong in both groups; girls had significantly longer median RTL than boys (1.8 versus 1.5, p < 0.01). Short RTL was associated with low forced expiratory flow, also after adjusting for gender, but was not affected by severity of BPD or ongoing inflammation.Conclusion: Telomere length was similar in 10-year-old children born preterm with a history of BPD and term born children with allergic asthma. However, impaired lung function and male gender were associated wrth short telomeres.
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| 319498. |
- Henckel, Laura, et al.
(författare)
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Assessing the usefulness of citizen science data for habitat suitability modelling: Opportunistic reporting versus sampling based on a systematic protocol
- 2020
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Ingår i: Diversity and Distributions. - : Wiley. - 1366-9516 .- 1472-4642. ; 26, s. 1276-1290
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Tidskriftsartikel (refereegranskat)abstract
- Aim To evaluate the potential of models based on opportunistic reporting (OR) compared to models based on data from a systematic protocol (SP) for modelling species distributions. We compared model performance for eight forest bird species with contrasting spatial distributions, habitat requirements and rarity. Differences in the reporting of species were also assessed. Finally, we tested potential improvement of models when inferring high-quality absences from OR based on questionnaires sent to observers. Location Both datasets cover the same large area (Sweden) and time period (2000-2013). Methods Species distributions were modelled using logistic regression. Predictive performance of OR models to predict SP data was assessed based on AUC. We quantified the congruence in spatial predictions using Spearman's rank correlation coefficient. We related these results to species characteristics and reporting behaviour of observers. We also assessed the gain in predictive performance of OR models by adding inferred absences. Finally, we investigated the potential impact of sampling bias in OR. Results For all species, and despite the sampling biases, results from OR overall agreed well with those of SP, for the nationwide spatial congruence of habitat suitability maps and the selection and directions of species-environment relationships. The OR models also performed well in predicting the SP data. The predictive performance of the OR models increased with species rarity and even outperformed the SP model for the rarest species. No significant impact of observer behaviour was found. Main conclusions Relatively simple analyses with inferred absences could produce reliable spatial predictions of habitat suitability. This was especially true for rare species. OR data should be seen as a complement to SP, as the weakness of one is the strength of the other, and OR may be especially useful at large spatial scales or where no systematic data collection protocols exist.
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| 319499. |
- Henckel, Sture
(författare)
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Tidig teknik väcker nyfikenhet
- 2009
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Ingår i: Ingenjören. - Stockholm : Sörmlands Grafiska AB. - 1101-8704. ; :4, s. 12-16
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- När barnen är som mest nyfikna anses de vara för små för naturvetenskap. När de sedan står med ena benet i vuxenvärlden och vill diskutera viktiga frågor ska de korvstoppas med fysikaliska fakta. Men det finns de som resonerar tvärtom. Små barn älskar fakta.
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| 319500. |
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