Changes in the size and structure of the nucleolus of columnar cells during their migration from crypt base to villus top in rat jejunum

1982 ◽  
Vol 56 (1) ◽  
pp. 83-99
Author(s):  
G.G. Altmann ◽  
C.P. Leblond
Keyword(s):  
Ribosomal Rna ◽  
The Other ◽  
Rat Jejunum ◽  
Differentiated Cells ◽  
Image Analyser ◽  
Single Structure ◽  
Columnar Cells ◽  
Crypt Base ◽  
Size And Structure ◽  
Nucleolar Components

An image analyser was used to measure the area of the nucleolus and its component parts in columnar cells at six levels of the jejunal epithelium, corresponding to stages in cell migration from crypt base to villus top. In columnar cells of crypt base, which function as stem cells for the epithelium, the nucleolus is large (3.1 micron2), irregular and reticulated. As cells migrate up the crypt, divide and differentiate, the nucleolus decreases in size (1.7 micron2) and becomes spherical, but remains reticulated. In the fully differentiated cells of the midvillus, however, the nucleolus becomes small (0.9 micron2) and compact. At the villus top, as the cells display early signs of degeneration, the nucleolus is further compacted (0.5 micron2). Most nucleolar components also decrease in size. Pars fibrosa (about 19% of the nucleolar area in crypt base) and pars granulosa (about 70%) decrease in proportion to the rest of the nucleolus, except in mid-villus and villus top where loss of pars granulosa predominates. In contrast, the total area of fibrillar centres remains constant (about 0.1 micron2), even though individual centres are small and numerous in crypt base, larger and fewer at higher levels, and they coalesce into a single structure in villus top. The other nucleolar components are also segregated into distinct, but adjacent, areas at this level. The changes in size and structure of the nucleolus taking place during the migration of columnar cells can be correlated with the maturation of the cells and the loss of their ability to synthesize ribosomal RNA.

Phylogeny of hymenolepidids (Cestoda: Cyclophyllidea) from mammals: sequences of 18S rRNA and COI genes confirm major clades revealed by the 28S rRNA analyses

2021 ◽  
Vol 95 ◽  
Author(s):  
B. Neov ◽  
G.P. Vasileva ◽  
G. Radoslavov ◽  
P. Hristov ◽  
D.T.J. Littlewood ◽  
...  
Keyword(s):  
Ribosomal Rna ◽  
18S Rrna ◽  
Phylogenetic Analyses ◽  
The Other ◽  
Rrna Genes ◽  
Host Switching ◽  
28S Rrna ◽  
Mitochondrial Cytochrome ◽  
Rapid Radiation ◽  
18S Rrna Genes

Abstract The aim of the study is to test a hypothesis for the phylogenetic relationships among mammalian hymenolepidid tapeworms, based on partial (D1–D3) nuclear 28S ribosomal RNA (rRNA) genes, by estimating new molecular phylogenies for the group based on partial mitochondrial cytochrome c oxidase I (COI) and nuclear 18S rRNA genes, as well as a combined analysis using all three genes. New sequences of COI and 18S rRNA genes were obtained for Coronacanthus integrus, C. magnihamatus, C. omissus, C. vassilevi, Ditestolepis diaphana, Lineolepis scutigera, Spasskylepis ovaluteri, Staphylocystis tiara, S. furcata, S. uncinata, Vaucherilepis trichophorus and Neoskrjabinolepis sp. The phylogenetic analyses confirmed the major clades identified by Haukisalmi et al. (Zoologica Scripta 39: 631–641, 2010): Ditestolepis clade, Hymenolepis clade, Rodentolepis clade and Arostrilepis clade. While the Ditestolepis clade is associated with soricids, the structure of the other three clades suggests multiple evolutionary events of host switching between shrews and rodents. Two of the present analyses (18S rRNA and COI genes) show that the basal relationships of the four mammalian clades are branching at the same polytomy with several hymenolepidids from birds (both terrestrial and aquatic). This may indicate a rapid radiation of the group, with multiple events of colonizations of mammalian hosts by avian parasites.

scholarly journals Rex-induced recombination implies bipolar organization of the ribosomal RNA genes of Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 120 (4) ◽  
pp. 1053-1059
Author(s):  
L G Robbins ◽  
E E Swanson
Keyword(s):  
Drosophila Melanogaster ◽  
Ribosomal Rna ◽  
Mitotic Recombination ◽  
Ribosomal Rna Genes ◽  
The Other ◽  
Other Orientation ◽  
Rna Genes ◽  
Nucleolus Organizers

Abstract Rex-induced mitotic recombination was used to determine whether nucleolus organizers can pair in both inverted and noninverted orientations. Two target chromosomes, each duplicated for the rDNA region, were exposed to maternal Rex activity. Recombination in one orientation should yield deletion of the material between the two nucleolus organizers, recombination in the other orientation should yield inversion of the same material. Both products were recovered from both target chromosomes. The generality of using Rex-mediated recombination for analysis of the rDNA is considered.

German Eugenics and the Wider World: Beyond the Racial State

2012 ◽  
Author(s):  
Paul Weindling
Keyword(s):  
Public Health ◽  
Welfare State ◽  
Ethnic Groups ◽  
Urban Growth ◽  
The Other ◽  
Racial Hygiene ◽  
Key Issues ◽  
Rapid Industrialization ◽  
The Individual ◽  
Size And Structure

This article discusses German eugenics as being incorporated of two strands, one racially oriented and the other welfare oriented. Eugenics in Germany was also characterized by its intention to reach out to a wider world of German colonies and German ethnic groups beyond the frontiers of the state. Key issues such as rapid industrialization and urban growth and associated changes in morbidity, family size and structure, and sexuality are addressed. The article outlines a system of public health in which eugenically-trained physicians served the race and nation rather than merely the individual. It provides an understanding of racial hygiene within the context of German imperialism, but the postwar loss of colonies, of territories to the new Polish state, creates a shift of focus within the new welfare state.

scholarly journals The Hippo–YAP Signaling as Guardian in the Pool of Intestinal Stem Cells

Biomedicines ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 560
Author(s):  
Yoojin Seo ◽  
So-Yeon Park ◽  
Hyung-Sik Kim ◽  
Jeong-Seok Nam
Keyword(s):  
Stem Cells ◽  
Intestinal Epithelium ◽  
Fine Tuning ◽  
Intestinal Stem Cells ◽  
Dynamic Regulation ◽  
Intestinal Integrity ◽  
Differentiated Cells ◽  
Quiescent Stem Cells ◽  
G Protein Coupled ◽  
Crypt Base

Despite endogenous insults such as mechanical stress and danger signals derived from the microbiome, the intestine can maintain its homeostatic condition through continuous self-renewal of the crypt–villus axis. This extraordinarily rapid turnover of intestinal epithelium, known to be 3 to 5 days, can be achieved by dynamic regulation of intestinal stem cells (ISCs). The crypt base-located leucine-rich repeat-containing G-protein-coupled receptor 5-positive (Lgr5+) ISCs maintain intestinal integrity in the steady state. Under severe damage leading to the loss of conventional ISCs, quiescent stem cells and even differentiated cells can be reactivated into stem-cell-like cells with multi-potency and contribute to the reconstruction of the intestinal epithelium. This process requires fine-tuning of the various signaling pathways, including the Hippo–YAP system. In this review, we summarize recent advances in understanding the correlation between Hippo–YAP signaling and intestinal homeostasis, repair, and tumorigenesis, focusing specifically on ISC regulation.

A new species and a new record of Xanthagaricus (Agaricaceae, Agaricales) from China

Phytotaxa ◽  
2018 ◽  
Vol 371 (4) ◽  
pp. 241 ◽  
Author(s):  
FENGJIAN WANG ◽  
LIANGLIANG QI ◽  
XIANGYU ZHOU ◽  
YU LI
Keyword(s):  
New Species ◽  
Molecular Analysis ◽  
Ribosomal Rna ◽  
Internal Transcribed Spacer ◽  
New Record ◽  
Morphological Features ◽  
The Other ◽  
Ribosomal Rna Gene ◽  
Micromorphological Characters ◽  
A New Species

Two species of Xanthagaricus discovered in Hubei Province of China are described based on the macro- and micromorphological features. Their identity is further supported by molecular analysis of the internal transcribed spacer (ITS) of the ribosomal RNA gene. The phylogeny obtained here showed that one of the Chinese species is nested in an exclusive clade which in combination with its striking morphological features, infers that it represents a new species, named X. ianthinus, while the other species is placed as a member in the X. epipastus clade. Descriptions are accompanied with illustrations of macro- and micromorphological characters and a discussion of related taxa is presented.

Patterns of Authority in West Africa

Africa ◽  
1951 ◽  
Vol 21 (4) ◽  
pp. 261-278 ◽  
Author(s):  
Paula Brown
Keyword(s):  
West Africa ◽  
Political System ◽  
West African ◽  
The Other ◽  
Political Structure ◽  
Political Relations ◽  
Comparative Review ◽  
Different Types ◽  
Opening Paragraph ◽  
Size And Structure

Opening ParagraphThe development of large centralized states in West Africa has long been recognized. The complexity of organization of the few well-known kingdoms, but not their differences in size and structure, is constantly emphasized in the literature. The number and variety of West African groups which have not developed states have, on the other hand, frequently been underestimated. In a comparative review by Professors Fortes and Evans-Pritchard two types of political system, centralized and segmentary, have been described for Africa as a whole, with examples of each in West Africa. A survey of West African societies suggests, however, that finer distinctions are possible and that not all these societies can be placed in one or other of these two categories. In particular, this classification omits consideration of ‘stateless’ societies in which associations, rather than a segmentary lineage system, regulate political relations; and it fails to distinguish different types of authority and political structure in states.

scholarly journals The complete chloroplast genome sequences of five pinnate-leaved Primula species and phylogenetic analyses

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Wenbin Xu ◽  
Boshun Xia ◽  
Xinwei Li
Keyword(s):  
Ribosomal Rna ◽  
Phylogenetic Analyses ◽  
Distinct Species ◽  
The Other ◽  
Trna Genes ◽  
Protein Coding ◽  
Complete Chloroplast Genome ◽  
Noncoding Sequences ◽  
Chloroplast Genomes ◽  
Rna Genes

AbstractThe six pinnate-leaved species are a very particular group in the genus Primula. In the present paper, we sequenced, assembled and annotated the chloroplast genomes of five of them (P. cicutarrifolia, P. hubeiensis, P. jiugongshanensis, P. merrilliana, P. ranunculoides). The five chloroplast genomes ranged from ~ 150 to 152 kb, containing 113 genes (four ribosomal RNA genes, 29 tRNA genes and 80 protein-coding genes). The six pinnate-leaved species exhibited synteny of gene order and possessed similar IR boundary regions in chloroplast genomes. The gene accD was pseudogenized in P. filchnerae. In the chloroplast genomes of the six pinnate-leaved Primula species, SSRs, repeating sequences and divergence hotspots were identified; ycf1 and trnH-psbA were the most variable markers among CDSs and noncoding sequences, respectively. Phylogenetic analyses showed that the six Primula species were separated into two distant clades: one was formed by P. filchnerae and P. sinensis and the other clade was consisting of two subclades, one formed by P. hubeiensis and P. ranunculoides, the other by P. merrilliana, P. cicutarrifolia and P. jiugongshanensis. P. hubeiensis was closely related with P. ranunculoides and therefore it should be placed into Sect. Ranunculoides. P. cicutarrifolia did not group first with P. ranunculoides but with P. merrilliana, although the former two were once united in one species, our results supported the separation of P. ranunculoides from P. cicutarrifolia as one distinct species.

A New Multiparametric Flow Cytometry Technique Based on Combined Side Population (SP) and Aldehyde Deshydrogenase (ALDH) Functionalities Identifies a Hierarchy within the Human Hematopoietic Stem/Progenitor Compartment.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2226-2226
Author(s):  
Olivier Pierre-Louis ◽  
Denis Clay ◽  
Bernadette Guerton ◽  
Christophe Desterke ◽  
Aurelie Chabanon ◽  
...  
Keyword(s):  
Stem Cells ◽  
Close Association ◽  
Scid Mice ◽  
The Other ◽  
Expression Level ◽  
Hierarchical Level ◽  
Hematopoietic Stem ◽  
Differentiated Cells ◽  
Progenitor Compartment

Abstract Hematopoietic stem cells (HSC) are characterized by their potential to reconstitute in vivo haematopoiesis in NOD/SCID mice and to give rise to differentiated cells of all haematopoietic lineages. They are usually defined by a CD34+CD38−CD90+ antigenic profile; however taking into account the versatility of antigen membrane expression (Lataillade et al., J. Leukoc. Biol. 2005), more reliable methods based on their selective functional/metabolic activities such as ABCG2 activity and Aldehyde Deshydrogenase expression have been developed. Actually, HSC can be purified on basis of Hoechst 33342 die exclusion property due to the membrane ABCG2/BRCP1 transporter expression (SP cells). SP cells could be isolated from a wide variety of human and mammalian tissues and in many cases have been shown to contain multipotent stem cells; SP cells are heterogeneous since the lowest Hoechst fluorescent profile exhibited the highest primitive hierarchical level. Hematopoietic progenitors also expressed ALDH enzymatic activity and the use of BODIPY-AminoAcetAldehyde (BAAA), a fluorescent substrate of the ALDH enzyme, allows analyzing its expression by using Fluorescence Activated Cell Sorting (FACS). It has been reported that there is a close association between high ALDH expression (ALDHbr) and high HSC activity. Based on the hypothesis that the more primitive HSC should express both ALDH high expression level and SP profile, we developed a new multiparamatric flow cytometric assay combining an ALDH/SP co-labelling to identify different haematopoietic progenitor subpopulations. Our strategy allows identifying six lineage negative (Lin−) haematopoietic sub-populations from human bone marrow cells according to the co-expression of ALDH levels and SP phenotype: SP+ALDHBr, SP−ALDHBr, SP+ALDHMid, SP−ALDHMid, SP+ALDHLo and SP-ALDHLo. We showed that these different sub-populations exhibited specific antigenic patterns and demonstrated variable differentiation properties in long term cultures and clonogenic assays. Whatever the ALDH expression level, SP+ and SP−cells expressed the CD34 antigen, however, the SP phenotype identify a higher proportion of CD34+CD38− cells. Furthermore, in contrast to the other subpopulations, Lin-SP+ALDHBr cells were highly enriched with CD34+CD38−CD90+ progenitor cells and demonstrated a higher amplification and high clonogenic efficiency in liquid LTC-IC cultures than SP-ALDHBr cells. This subpopulation allowed obtaining all myeloid haematopoietic lineage differentiated cells after 30 days culture in liquid culture, including osteoclastic cells. Interestingly, in contrast to ALDHBr cells, ALDHLo sub-populations were highly enriched with megakaryocytic CD34+CD41+ progenitors that gave rise to CD41+CD42a+ cells. SP+ALDHMid and SP-ALDHMid have intermediate amplification, clonogenic and differentiation abilities as compared with the other subpopulations. In conclusion, our results show that the combined SP/ALDH technology allows discriminating a hierarchy within the human hematopoietic stem/progenitor compartment, the most primitive one being SP+ALDHBr. The stemness of these subpopulations is currently explored by testing their capability to reconstitute long term haematopoiesis in NOD/SCID mice.

scholarly journals Expression of a marker for colonic crypt base cells is correlated with poor prognosis in human colorectal cancer

Gut ◽  
1998 ◽  
Vol 42 (1) ◽  
pp. 63-70 ◽  
Author(s):  
A A M van der Wurff ◽  
J ten Kate ◽  
P T J Marx ◽  
E P M van der Linden ◽  
C C L Beek ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Poor Prognosis ◽  
Colonic Mucosa ◽  
Tumour Progression ◽  
Colonic Crypt ◽  
Human Colorectal Cancer ◽  
Colon Crypt ◽  
Differentiated Cells ◽  
Crypt Base ◽  
Worse Prognosis

Background—There is a need for markers in colorectal cancer which will allow subclassification of stage groups into subgroups with high versus low risk of recurrent disease.Aims—To develop monoclonal antibodies that recognise antigens on immature crypt base cells, on the assumption that in a neoplasm undifferentiated but not the terminally differentiated cells will be responsible for tumour progression.Methods—Colon crypt cells which were isolated from human colonic mucosa by EDTA/EGTA incubation were studied. By stepwise harvesting, crypt base cell enriched fractions were obtained, and after incubation with antibodies against dominant antigens, used as immunogens.Results—Of one crypt base cell specific antibody (5E9), the reactive epitope appeared to be a non-terminal carbohydrate in the mucin O-glycans of the colon. The epitope did not seem to be colon specific, but was expressed in a variety of other tissues. In colorectal carcinomas, 5E9 immunoreactivity identified a subgroup of patients with a tendency for worse prognosis.Conclusion—A mucin associated maturation epitope was identified in colonic crypt base cells, the expression of which in Dukes’ stage B3 colorectal carcinoma may be associated with poor prognosis.

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