scholarly journals Active and inactive genes localize preferentially in the periphery of chromosome territories.

1996 ◽  
Vol 135 (5) ◽  
pp. 1195-1205 ◽  
Author(s):  
A Kurz ◽  
S Lampel ◽  
J E Nickolenko ◽  
J Bradl ◽  
A Benner ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Three Dimensional ◽  
Cell Types ◽  
Chromosome Territory ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Chromosome Territories ◽  
Inactive Genes ◽  
Different Cell Types ◽  
The Impact

The intranuclear position of a set of genes was analyzed with respect to the territories occupied by the whole chromosomes in which these genes are localized. Genes and their respective chromosome territories were simultaneously visualized in three-dimensionally preserved nuclei applying dual color fluorescence in situ hybridization. Three coding (DMD, MYH7, and HBB) and two noncoding sequences (D1Z2 and an anonymous sequence) were analyzed in four different cell types, including cells where DMD and MYH7 are actively transcribed. Spatial analysis by confocal laser scanning microscopy revealed that the genes are preferentially located in the periphery of chromosome territories. This positioning was independent from the activity of the genes. In contrast, the non-expressed anonymous fragment was found randomly distributed or localized preferentially in the interior of the corresponding chromosome territory. Furthermore, the distribution of the analyzed genes within the territorial peripheries was found to be highly characteristic for each gene, and, again, independent from its expression. The impact of these findings with regard to the three-dimensional arrangement of the linear DNA string within chromosome territories, as well as with respect to a putative nuclear subcompartment confining gene expression, are discussed.

Aspects of three-dimensional chromosome reorganization during the onset of human male meiotic prophase

1998 ◽  
Vol 111 (16) ◽  
pp. 2337-2351 ◽  
Author(s):  
H. Scherthan ◽  
R. Eils ◽  
E. Trelles-Sticken ◽  
S. Dietzel ◽  
T. Cremer ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Voronoi Tessellation ◽  
Three Dimensional ◽  
Complex Surface ◽  
Laser Scanning Microscopy ◽  
Homology Search ◽  
Confocal Laser ◽  
Human Testis ◽  
Chromosome Territories ◽  
Painted Chromosome

The three-dimensional morphology and distribution of human chromosomes 3 were studied in nuclei of spermatogonia and spermatocytes I from formaldehyde-fixed human testis sections. Chromosome arms, pericentromeres and telomeric regions were painted by a three-color, five-probe fluorescence in situ hybridization protocol. Light optical serial sections of premeiotic and meiotic nuclei obtained by confocal laser scanning microscopy revealed that premeiotic chromosomes 3 are separate from each other and occupy variably shaped territories, which are sectored in distinct 3 p- and q-arm domains. Three-dimensional reconstructions of the painted chromosome domains by a Voronoi tessellation approach showed that mean chromosome volumes did not differ significantly among the premeiotic and meiotic stages investigated. A significant increase in surface area and reduction of dimensionless ‘roundness factor’ estimates of arm domains indicated that the restructuring of spatially separate chromosome territories initiates during preleptotene. Telomeric regions, which in meiotic stem cells located predominantly in arm-domain chromatin, showed a redistribution towards the domain surface during this stage. At leptotene homologues were generally misaligned and displayed intimate intermingling of non-homologous chromatin. Pairing initiated at the ends of bent zygotene chromosomes, which displayed a complex surface structure with discernible sister chromatids. The results indicate that, in mammals, homology search is executed during leptotene, after remodeling of chromosome territories.

Different patterns of rDNA distribution in Pisum sativum nucleoli correlate with different levels of nucleolar activity

1993 ◽  
Vol 104 (3) ◽  
pp. 843-852 ◽  
Author(s):  
M. I. Highett ◽  
D. J. Rawlins ◽  
P. J. Shaw
Keyword(s):  
Pisum Sativum ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Ccd Camera ◽  
Cell Types ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Wide Field ◽  
Root Tips ◽  
Root Cells

We have used in situ hybridization with probes to rDNA, labelled either with digoxygenin or directly with fluorescein, to determine the arrangement of these genes within the nucleoli of Pisum sativum L. root cells. Confocal laser scanning microscopy was used to image the three-dimensional structures revealed, but we have also compared this technique with deconvolution of conventional (wide-field) fluorescence images measured with a cooled CCD camera, and have shown that the results are remarkably similar. When the deconvolution technique was applied to the confocal data it gave clearer images than could be achieved by confocal microscopy alone. We have analysed the distribution of rDNA in the different cell types observable in root tips: the quiescent centre; active meristematic cells; and relatively differentiated root cap, epidermal and cortical cells. In addition to four perinucleolar knobs of condensed, inactive rDNA genes, corresponding to the four nucleolar organizers in P. sativum, which were the most brightly labelled structures, several characteristic patterns of intranucleolar labelling were apparent, including bright foci, large central chromatin masses, and fine, decondensed interconnecting fibres. The larger and more active the nucleolus, the smaller the proportion of condensed perinucleolar rDNA. In some large and active meristematic nucleoli, all the internal rDNA is decondensed, showing that transcription cannot be restricted to the bright foci, and is most likely to occur on the decondensed fibres.

Confocal and SEM imaging to demonstrate food pathogen- biofilm biocontrol by pyocyanin from Pseudomonas aeruginosa BTRY1

2016 ◽  
Vol 6 (01) ◽  
pp. 5218
Author(s):  
Laxmi Mohandas ◽  
Anju T. R. ◽  
Sarita G. Bhat*
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Laser Scanning ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Antibiofilm Activity ◽  
Opportunistic Pathogens ◽  
Redox Active ◽  
Sem Imaging ◽  
The Impact

An assortment of redox-active phenazine compounds like pyocyanin with their characteristic blue-green colour are synthesized by Pseudomonas aeruginosa, Gram-negative opportunistic pathogens, which are also considered one of the most commercially valuable microorganisms. In this study, pyocyanin from Pseudomonas aeruginosa BTRY1 from food sample was assessed for its antibiofilm activity by micro titer plate assay against strong biofilm producers belonging to the genera Bacillus, Staphylococcus, Brevibacterium and Micrococcus. Pyocyanin inhibited biofilm activity in very minute concentrations. This was also confirmed by Scanning Electron Microscopy (SEM) and Confocal Laser Scanning Microscopy (CLSM). Both SEM and CLSM helped to visualize the biocontrol of biofilm formation by eight pathogens. The imaging and quantification by CLSM also established the impact of pyocyanin on biofilm-biocontrol mainly in the food industry.

Behaviour of nucleolar proteins in nuclei lacking ribosomal genes. A study by confocal laser scanning microscopy

1991 ◽  
Vol 98 (1) ◽  
pp. 99-105
Author(s):  
D. Hernandez-Verdun ◽  
M. Robert-Nicoud ◽  
G. Geraud ◽  
C. Masson
Keyword(s):  
Confocal Laser Scanning Microscopy ◽  
Laser Scanning ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Confocal Laser Scanning ◽  
Scanning Microscopy ◽  
Confocal Laser ◽  
Specific Marker ◽  
Nucleolar Proteins ◽  
Fibrillar Component

The behaviour of nucleolar proteins in cycling PtK1 cells and in micronuclei with or without NORs was investigated by immunofluorescence using antibodies from autoimmune sera and confocal laser scanning microscopy. These antibodies were shown by electron microscopy to recognize antigens confined to only one of the three basic nucleolar components: fibrillar centres (FC), dense fibrillar component (DFC) and granular component (GC). Serial optical sections allowed us to determine the three-dimensional organization of these components in the nucleolus of cycling cells. Furthermore, clear differences were found in the distribution of the various antigens in micronucleated cells. Three patterns could be observed: (1) the FC antigens were found mainly in the nucleoli, but also in varying amounts in the dots; (2) surprisingly, the DFC antigens were found to accumulate preferentially in the dots; (3) the GC-specific marker stained intensively the nucleoli as well the dots. The results are interpreted with regard to possible mechanisms for targeting nucleolar proteins to the site of nucleolar formation.

scholarly journals The effect of the dispersion of microfibrillated cellulose on the mechanical properties of melt-compounded polypropylene–polyethylene copolymer

Cellulose ◽  
2019 ◽  
Vol 26 (18) ◽  
pp. 9645-9659 ◽  
Author(s):  
Caterina Palange ◽  
Marcus A. Johns ◽  
David J. Scurr ◽  
Jonathan S. Phipps ◽  
Stephen J. Eichhorn
Keyword(s):  
Tannic Acid ◽  
Laser Scanning ◽  
Secondary Ion Mass Spectrometry ◽  
High Surface ◽  
Microfibrillated Cellulose ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Cellulose Content ◽  
Reinforced Composites ◽  
The Impact

Abstract Microfibrillated cellulose (MFC) is a highly expanded, high surface area networked form of cellulose-based reinforcement. Due to the poor compatibility of cellulose with most common apolar thermoplastic matrices, the production of cellulose-reinforced composites in industry is currently limited to polar materials. In this study, a facile water-based chemistry, based on the reaction of MFC with tannic acid and subsequent functionalisation with an alkyl amine, is used to render the surface of the MFC fibrils hydrophobic and enhance the dispersion of the cellulose-based filler into an apolar thermoplastic matrix. The level of dispersion of the compatibilized MFC reinforced composites was evaluated using Time of Flight Secondary Ion Mass Spectrometry and multi-channel Spectral Confocal Laser Scanning Microscopy. The agglomeration of cellulosic filler within the composites was reduced by functionalising the surface of the MFC fibrils with tannic acid and octadecylamine. The resulting composites exhibited an increase in modulus at a high cellulose content. Despite the dispersion of a large portion of the functionalised filler, the presence of some remaining aggregates affected the impact properties of the composites produced.

scholarly journals Software-Based Three-Dimensional Deconvolution Microscopy of Cytoskeletal Proteins in Cultured Fibroblast Using Open-Source Software and Open Hardware

2019 ◽  
Vol 5 (12) ◽  
pp. 88
Author(s):  
Kazuo Katoh
Keyword(s):  
Open Source ◽  
Open Source Software ◽  
Laser Scanning ◽  
Low Cost ◽  
Three Dimensional ◽  
Cytoskeletal Proteins ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Actual Measurement ◽  
Open Hardware

As conventional fluorescence microscopy and confocal laser scanning microscopy generally produce images with blurring at the upper and lower planes along the z-axis due to non-focal plane image information, the observation of biological images requires “deconvolution.” Therefore, a microscope system’s individual blur function (point spread function) is determined theoretically or by actual measurement of microbeads and processed mathematically to reduce noise and eliminate blurring as much as possible. Here the author describes the use of open-source software and open hardware design to build a deconvolution microscope at low cost, using readily available software and hardware. The advantage of this method is its cost-effectiveness and ability to construct a microscope system using commercially available optical components and open-source software. Although this system does not utilize expensive equipment, such as confocal and total internal reflection fluorescence microscopes, decent images can be obtained even without previous experience in electronics and optics.

scholarly journals Protocol for rapid clearing and staining of fixed Arabidopsis ovules for improved imaging by confocal laser scanning microscopy

Plant Methods ◽  
2019 ◽  
Vol 15 (1) ◽  
Author(s):  
Rachele Tofanelli ◽  
Athul Vijayan ◽  
Sebastian Scholz ◽  
Kay Schneitz
Keyword(s):  
Laser Scanning ◽  
Developmental Stages ◽  
Imaging Techniques ◽  
Three Dimensional ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Imaging Data ◽  
Model Species ◽  
Cellular Models ◽  
Cellular Resolution

Abstract Background A salient topic in developmental biology relates to the molecular and genetic mechanisms that underlie tissue morphogenesis. Modern quantitative approaches to this central question frequently involve digital cellular models of the organ or tissue under study. The ovules of the model species Arabidopsis thaliana have long been established as a model system for the study of organogenesis in plants. While ovule development in Arabidopsis can be followed by a variety of different imaging techniques, no experimental strategy presently exists that enables an easy and straightforward investigation of the morphology of internal tissues of the ovule with cellular resolution. Results We developed a protocol for rapid and robust confocal microscopy of fixed Arabidopsis ovules of all stages. The method combines clearing of fixed ovules in ClearSee solution with marking the cell outline using the cell wall stain SCRI Renaissance 2200 and the nuclei with the stain TO-PRO-3 iodide. We further improved the microscopy by employing a homogenous immersion system aimed at minimizing refractive index differences. The method allows complete inspection of the cellular architecture even deep within the ovule. Using the new protocol we were able to generate digital three-dimensional models of ovules of various stages. Conclusions The protocol enables the quick and reproducible imaging of fixed Arabidopsis ovules of all developmental stages. From the imaging data three-dimensional digital ovule models with cellular resolution can be rapidly generated using image analysis software, for example MorphographX. Such digital models will provide the foundation for a future quantitative analysis of ovule morphogenesis in a model species.

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