scholarly journals To Be or Not to Be Expressed: The First Evidence of a Nucleolar Dominance Tissue-Specificity in Brachypodium hybridum

2021 ◽  
Vol 12 ◽  
Author(s):  
Natalia Borowska-Zuchowska ◽  
Ewa Robaszkiewicz ◽  
Serhii Mykhailyk ◽  
Joanna Wartini ◽  
Artur Pinski ◽  
...  
Keyword(s):  
Tissue Specificity ◽  
Microscopic Analysis ◽  
Genotype 3 ◽  
Genome Composition ◽  
Developmentally Regulated ◽  
D Genome ◽  
Nucleolar Dominance ◽  
35S Rdna ◽  
Mother Cells

Nucleolar dominance (ND) is an epigenetic, developmentally regulated phenomenon that describes the selective inactivation of 35S rDNA loci derived from one progenitor of a hybrid or allopolyploid. The presence of ND was documented in an allotetraploid grass, Brachypodium hybridum (genome composition DDSS), which is a polyphyletic species that arose from crosses between two putative ancestors that resembled the modern B. distachyon (DD) and B. stacei (SS). In this work, we investigated the developmental stability of ND in B. hybridum genotype 3-7-2 and compared it with the reference genotype ABR113. We addressed the question of whether the ND is established in generative tissues such as pollen mother cells (PMC). We examined condensation of rDNA chromatin by fluorescence in situ hybridization employing state-of-art confocal microscopy. The transcription of rDNA homeologs was determined by reverse-transcription cleaved amplified polymorphic sequence analysis. In ABR113, the ND was stable in all tissues analyzed (primary and adventitious root, leaf, and spikes). In contrast, the 3-7-2 individuals showed a strong upregulation of the S-genome units in adventitious roots but not in other tissues. Microscopic analysis of the 3-7-2 PMCs revealed extensive decondensation of the D-genome loci and their association with the nucleolus in meiosis. As opposed, the S-genome loci were always highly condensed and localized outside the nucleolus. These results indicate that genotype-specific loss of ND in B. hybridum occurs probably after fertilization during developmental processes. This finding supports our view that B. hybridum is an attractive model to study ND in grasses.

Molecular and Microscopic Analysis of Altered Gene Expression in Transgenic and Gene Targeted Mice

1996 ◽  
Vol 54 ◽  
pp. 12-13
Author(s):  
W. K. Jones ◽  
J. Robbins
Keyword(s):  
Gene Expression ◽  
Pulmonary Veins ◽  
Microscopic Analysis ◽  
Mouse Tissue ◽  
Adult Heart ◽  
Heavy Chains ◽  
Altered Gene Expression ◽  
Altered Gene ◽  
Pulmonary Myocardium

Two myosin heavy chains (MyHC) are expressed in the mammalian heart and are differentially regulated during development. In the mouse, the α-MyHC is expressed constitutively in the atrium. At birth, the β-MyHC is downregulated and replaced by the α-MyHC, which is the sole cardiac MyHC isoform in the adult heart. We have employed transgenic and gene-targeting methodologies to study the regulation of cardiac MyHC gene expression and the functional and developmental consequences of altered α-MyHC expression in the mouse.We previously characterized an α-MyHC promoter capable of driving tissue-specific and developmentally correct expression of a CAT (chloramphenicol acetyltransferase) marker in the mouse. Tissue surveys detected a small amount of CAT activity in the lung (Fig. 1a). The results of in situ hybridization analyses indicated that the pattern of CAT transcript in the adult heart (Fig. 1b, top panel) is the same as that of α-MyHC (Fig. 1b, lower panel). The α-MyHC gene is expressed in a layer of cardiac muscle (pulmonary myocardium) associated with the pulmonary veins (Fig. 1c). These studies extend our understanding of α-MyHC expression and delimit a third cardiac compartment.

scholarly journals New from Old: Thorectandrin Alkaloids in a Southern Australian Marine Sponge, Thorectandra choanoides (CMB-01889)

Marine Drugs ◽  
2021 ◽  
Vol 19 (2) ◽  
pp. 97
Author(s):  
Shamsunnahar Khushi ◽  
Angela A. Salim ◽  
Ahmed H. Elbanna ◽  
Laizuman Nahar ◽  
Robert J. Capon
Keyword(s):  
Marine Sponge ◽  
Tissue Specificity ◽  
Spectroscopic Analysis ◽  
Transformation Products ◽  
Chemical Fractionation ◽  
Cancer Tissue ◽  
Michael Acceptor ◽  
Michael Acceptors ◽  
Stable Ring

Thorectandra choanoides (CMB-01889) was prioritized as a source of promising new chemistry from a library of 960 southern Australian marine sponge extracts, using a global natural products social (GNPS) molecular networking approach. The sponge was collected at a depth of 45 m. Chemical fractionation followed by detailed spectroscopic analysis led to the discovery of a new tryptophan-derived alkaloid, thorectandrin A (1), with the GNPS cluster revealing a halo of related alkaloids 1a–1n. In considering biosynthetic origins, we propose that Thorectandrachoanoides (CMB-01889) produces four well-known alkaloids, 6-bromo-1′,8-dihydroaplysinopsin (2), 6-bromoaplysinopsin (3), aplysinopsin (4), and 1′,8-dihydroaplysinopsin (10), all of which are susceptible to processing by a putative indoleamine 2,3-dioxygenase-like (IDO) enzyme to 1a–1n. Where the 1′,8-dihydroalkaloids 2 and 10 are fully transformed to stable ring-opened thorectandrins 1 and 1a–1b, and 1h–1j, respectively, the conjugated precursors 3 and 4 are transformed to highly reactive Michael acceptors that during extraction and handling undergo complete transformation to artifacts 1c–1g, and 1k–1n, respectively. Knowledge of the susceptibility of aplysinopsins as substrates for IDOs, and the relative reactivity of Michael acceptor transformation products, informs our understanding of the pharmaceutical potential of this vintage marine pharmacophore. For example, the cancer tissue specificity of IDOs could be exploited for an immunotherapeutic response, with aplysinopsins transforming in situ to Michael acceptor thorectandrins, which covalently bind and inhibit the enzyme.

Chromosomal organization of a sequence related to LTR-like elements of Ty1-copia retrotransposons in Avena species

Genome ◽  
1999 ◽  
Vol 42 (4) ◽  
pp. 706-713 ◽  
Author(s):  
Concha Linares ◽  
Antonio Serna ◽  
Araceli Fominaya
Keyword(s):  
In Situ Hybridization ◽  
Diploid Species ◽  
D Genome ◽  
Specific Sequence ◽  
Chromosomal Organization ◽  
Intergenomic Translocations ◽  
A Genome ◽  
Slot Blot Analysis ◽  
Copia Retrotransposons

A repetitive sequence, pAs17, was isolated from Avena strigosa (As genome) and characterized. The insert was 646 bp in length and showed 54% AT content. Databank searches revealed its high homology to the long terminal repeat (LTR) sequences of the specific family of Ty1-copia retrotransposons represented by WIS2-1A and Bare. It was also found to be 70% identical to the LTR domain of the WIS2-1A retroelement of wheat and 67% identical to the Bare-1 retroelement of barley. Southern hybridizations of pAs17 to diploid (A or C genomes), tetraploid (AC genomes), and hexaploid (ACD genomes) oat species revealed that it was absent in the C diploid species. Slot-blot analysis suggested that both diploid and tetraploid oat species contained 1.3 × 104 copies, indicating that they are a component of the A-genome chromosomes. The hexaploid species contained 2.4 × 104 copies, indicating that they are a component of both A- and D-genome chromosomes. This was confirmed by fluorescent in situ hybridization analyses using pAs17, two ribosomal sequences, and a C-genome specific sequence as probes. Further, the chromosomes involved in three C-A and three C-D intergenomic translocations in Avena murphyi (AC genomes) and Avena sativa cv. Extra Klock (ACD genomes), respectively, were identified. Based on its physical distribution and Southern hybridization patterns, a parental retrotransposon represented by pAs17 appears to have been active at least once during the evolution of the A genome in species of the Avena genus.Key words: chromosomal organization, in situ hybridization, intergenomic translocations, LTR sequence, oats.

C-banding and fluorescence in situ hybridization studies of the wheat–alien hybrid 'Agrotana'

Genome ◽  
1994 ◽  
Vol 37 (3) ◽  
pp. 477-481 ◽  
Author(s):  
Jie Xu ◽  
R. L. Conner ◽  
A. Laroche
Keyword(s):  
In Situ Hybridization ◽  
Fluorescence In Situ Hybridization ◽  
Genomic Dna ◽  
Chromosome Engineering ◽  
C Banding ◽  
Chinese Spring Wheat ◽  
Mother Cells ◽  
Alien Chromatin ◽  
Chromosome Segments

'Agrotana', a wheat-alien hybrid (2n = 56), is a potential source of resistance to common root rot, stem rust, wheat streak mosaic virus, and the wheat curl mite. However, the origin of 'Agrotana', reported to be durum wheat × Agropyron trichophorum (pubescent wheatgrass), is uncertain. The objective of this investigation was to determine the chromosome constitution of 'Agrotana' using C-banding and fluorescence in situ hybridization techniques. The F1 hybrid of 'Agrotana' × 'Chinese Spring' wheat showed 7 I + 21 II in 14.9% of the pollen mother cells, evidence of the presence of the A, B, and D genomes in 'Agrotana'. The hybrid had 16 heavily C-banded chromosomes, namely 4A, and 1-7B of wheat, and a translocation that probably involved wheat chromosomes 2A and 2D. In situ hybridization using biotinylated genomic DNA of Ag. trichophorum cv. Greenleaf blocked with CS DNA failed to identify the alien chromosomes in 'Agrotana', indicating that the alien chromosomes were not likely derived from pubescent wheatgrass. In situ hybridization using labelled wheat genomic DNA blocked with 'Agrotana' DNA revealed that 'Agrotana' had 40 wheat, 14 alien, and 2 (a pair) wheat–alien translocated chromosomes. There was no homology between wheat and the alien chromosomes or chromosome segments involved in the wheat–alien recombinant. Two of the seven pairs of alien chromosomes were homoeologous to each other. The ability to identify alien chromatin in wheat using labelled wheat DNA instead of labelled alien DNA will be particularly useful in chromosome engineering of wheat germplasms having alien chromatin of unknown origin.Key words: wheat–alien hybrid, C-banding, fluorescence in situ hybridization, labelled wheat DNA as probe.

Research on In Situ Anionic Polymerization of PA6/PI Alloy

2011 ◽  
Vol 295-297 ◽  
pp. 21-25
Author(s):  
Hong Kai Zhao ◽  
Li Guang Xiao ◽  
Hong Jie Wang
Keyword(s):  
Molecular Weight ◽  
Bisphenol A ◽  
High Performance ◽  
Hot Spot ◽  
Microscopic Analysis ◽  
Infrared Analysis ◽  
Elongation At Break ◽  
System Temperature ◽  
Lamellar Crystals

High performance trend of plastics has become a hot spot of current research. Select bisphenol A dianhydride and bisphenol A diamine with excellent water resistance as the reactant monomers to obtain anhydride-terminated polyimide with very high molecular weight by two-step polymerization, graft the active radicals of acyl caprolactam using the activity of anhydride and obtain PI modified nylon resin by polymerization.When the system temperature is above 160 °C and the added modifiers are greater than 10%, the system viscosity increases very fast; when the system temperature reaches 140 °C and the added modifiers are at 5%, the system viscosity increases very slowly. It is proved that the reaction in each above step is successful through infrared analysis. The mechanical properties of modified PI nylon increases with the increase of consumption and molecular weight of polyimide, when the molecular weight is selected to be about 8000~10000 and the adding amount is 10wt%~15 wt%, the tensile strength reaches over 85MPa, the notch impact strength is increased to 19.6kJ.m-2 and the elongation at break reaches 18%, which are remarkably better than general engineering plastics.Through microscopic analysis, the molecules of polyimide does not enter crystallization phase of nylon resin, but forms compact lamellar crystals existing in nylon matrix.

scholarly journals In situ microscopic analysis of asbestos and synthetic vitreous fibers retained in hamster lungs following inhalation.

1999 ◽  
Vol 107 (5) ◽  
pp. 367-375 ◽  
Author(s):  
R A Rogers ◽  
J M Antonini ◽  
H Brismar ◽  
J Lai ◽  
T W Hesterberg ◽  
...  
Keyword(s):  
Microscopic Analysis

scholarly journals Effect of Hydrogen Peroxide at 35% on the Morphology of Enamel and Interference in the De-remineralization Process: An In Situ Study

2012 ◽  
Vol 37 (5) ◽  
pp. 518-525 ◽  
Author(s):  
AM de Arruda ◽  
PH dos Santos ◽  
RH Sundfeld ◽  
SB Berger ◽  
ALF Briso
Keyword(s):  
Hydrogen Peroxide ◽  
Dental Caries ◽  
Microscopic Analysis ◽  
Enamel Surface ◽  
In Situ Study ◽  
Bovine Enamel ◽  
Histologic Changes

SUMMARY This study evaluated the microhardness and histomorphology of bovine enamel when 35% hydrogen peroxide is used. A total of 44 specimens were adapted to removable devices used by 11 individuals subjected to dental caries challenge. A decrease in microhardness was observed for all groups after the cariogenic challenge. Microscopic analysis revealed that fragments subjected to cariogenic challenge associated with bleaching had more intense superficial histologic changes, but the depth of the lesions remained unchanged. It was concluded that 35% hydrogen peroxide enhanced the reduction in hardness and histomorphologic changes in the enamel surface exposed to cariogenic challenge.

scholarly journals The Drosophila couch potato gene: an essential gene required for normal adult behavior.

Genetics ◽  
1992 ◽  
Vol 131 (2) ◽  
pp. 365-375 ◽  
Author(s):  
H J Bellen ◽  
H Vaessin ◽  
E Bier ◽  
A Kolodkin ◽  
D D'Evelyn ◽  
...  
Keyword(s):  
Nervous System ◽  
Essential Gene ◽  
Flight Behavior ◽  
Regulatory Sequences ◽  
Adult Behavior ◽  
The Central Nervous System ◽  
Enhancer Detection ◽  
Dna Fragment ◽  
Mother Cells

Abstract Through enhancer detection screens we have isolated 14 insertions in an essential gene that is expressed in embryonic sensory mother cells (SMC), in most cells of the mature embryonic peripheral nervous system (PNS), and in glial cells of the PNS and the central nervous system (CNS). Embryos homozygote for amorphic alleles die, but show no obvious defects in their cuticle, PNS or CNS. The gene has been named couch potato (cpo) because several insertional alleles alter adult behavior. Homozygous hypomorphic cpo flies recover slowly from ether anaesthesia, show aberrant flight behavior, fail to move toward light and do not exhibit normal negative behavior. However, the flies are able to groom and walk, and some are able to fly when prodded, indicating that not all processes required for behavior are severely affected. A molecular analysis shows that the 14 insertions are confined to a few hundred nucleotides which probably contain key regulatory sequences of the gene. The orientation of these insertions and their position within this DNA fragment play an important role in the couch potato phenotype. In situ hybridization to whole mount embryos suggest that some insertions affect the levels of transcription of cpo in most cells in which it is expressed.

Research on Performance of Polyimide In Situ Modification Anionic Polymerization Nylon 6

2014 ◽  
Vol 1052 ◽  
pp. 242-248
Author(s):  
Hong Kai Zhao ◽  
Hong Li Wang
Keyword(s):  
Bisphenol A ◽  
Water Absorption ◽  
In Situ Polymerization ◽  
Microscopic Analysis ◽  
Nylon 6 ◽  
Grafting Reaction ◽  
Lamellar Crystals ◽  
End Capping ◽  
Short Time

Through the polymerization and grafting reaction of bisphenol A dianhydride and bisphenol A diamine, the polyimide activator (PI activator) of acyl caprolactam end capping is obtained and then the anionic in-situ polymerization modified nylon 6 resin is obtained. Viscosity analysis shows that PI consumption is higher than 0.1 (of monomer mass), the reaction temperature is higher than 160°C, the viscosity rises rapidly in a short time and the rapid polymerization molding can be realized; when PI consumption is higher than 0.15 (of monomer mass), the water absorption of matrix resin will be lower than 1.4%; compared with the nylon resin, its water absorption is significantly lowered and its mechanical property is improved greatly; microscopic analysis shows that PI molecules fail to enter the crystalline phase of the nylon 6 and form lamellar crystals in the nylon matrix, which plays a role of enhancement and obstruction; differential thermal analysis shows that PI reduces the melting enthalpy and melting point temperature of nylon 6 resin, which indicates that PI reduces the crystallization capacity of nylon 6.

scholarly journals Technical Note: Determination of the metabolically active fraction of benthic foraminifera by means of Fluorescent In Situ Hybridization (FISH)

2011 ◽  
Vol 8 (8) ◽  
pp. 2075-2088 ◽  
Author(s):  
C. Borrelli ◽  
A. Sabbatini ◽  
G. M. Luna ◽  
M. P. Nardelli ◽  
T. Sbaffi ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Benthic Foraminifera ◽  
Fluorescent In Situ Hybridization ◽  
Microscopic Analysis ◽  
Technical Note ◽  
Physiological Status ◽  
Hybridization Technique ◽  
Marine Biota ◽  
Classical Studies

Abstract. Benthic foraminifera are an important component of the marine biota, but protocols for investigating their viability and metabolism are still extremely limited. Classical studies on benthic foraminifera have been based on direct counting under light microscopy. Typically, these organisms are stained with Rose Bengal, which binds proteins and other macromolecules, but does not allow discrimination between viable and recently dead organisms. The fluorescent in situ hybridization technique (FISH) represents a new and useful approach to identify living cells possessing an active metabolism. Our work is the first test of the suitability of the FISH technique, based on fluorescent probes targeting the 18S rRNA, to detect live benthic foraminifera. The protocol was applied on Ammonia group and Miliolids, as well as on agglutinated polythalamous (i.e., Leptohalysis scottii and Eggerella scabra) and soft-shelled monothalamous (i.e., Psammophaga sp. and saccamminid morphotypes) taxa. The results from FISH analyses were compared with those obtained, on the same specimens assayed with FISH, from microscopic analysis of the cytoplasm colour, presence of pigments and pseudopodial activity. Our results indicate that FISH targets only metabolically active foraminifera, and allows discerning from low to high cellular activity, validating the hypothesis that the intensity of the fluorescent signal emitted by the probe is dependent upon the physiological status of cells. These findings support the usefulness of this molecular approach as a key tool for obtaining information on the physiology of living foraminifera, both in field and experimental settings.

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