scholarly journals Early Embryonic Lethality in Mice with Targeted Deletion of the CTP:Phosphocholine Cytidylyltransferase α Gene (Pcyt1a)

2005 ◽  
Vol 25 (8) ◽  
pp. 3357-3363 ◽  
Author(s):  
Limin Wang ◽  
Susan Magdaleno ◽  
Ira Tabas ◽  
Suzanne Jackowski
Keyword(s):  
Fetal Liver ◽  
Isolated Hepatocytes ◽  
Methyl Transferase ◽  
Targeted Deletion ◽  
Ctp:Phosphocholine Cytidylyltransferase ◽  
Choline Incorporation ◽  
Early Embryonic Lethality ◽  
Mice Liver ◽  
Rate Controlling Step

ABSTRACT CTP:phosphocholine cytidylyltransferase (CCT) catalyzes a rate-controlling step in the biosynthesis of phosphatidylcholine (PtdCho). Multiple CCT isoforms, CCTα, CCTβ2, and CCTβ3, are encoded by two genes, Pcyt1a and Pcyt1b. The importance of CCTα in mice was investigated by deleting exons 5 and 6 in the Pcyt1a gene using the Cre-lox system. Pcyt1a − / − zygotes failed to form blastocysts, did not develop past embryonic day 3.5 (E3.5), and failed to implant. In situ hybridization in E11.5 embryos showed that Pcyt1a is expressed ubiquitously, with the highest level in fetal liver, and CCTα transcripts are significantly more abundant than transcripts encoding CCTβ or phosphatidylethanolamine (PtdEtn) N-methyl transferase, two other enzymes capable of producing PtdCho. Reduction of the CCTα transcripts in heterozygous E11.5 embryos was accompanied by upregulation of CCTβ and PtdEtn N-methyltransferase transcripts. In contrast, enzymatic and real-time PCR data revealed that CCTβ (Pcyt1b) expression is not upregulated to compensate for the reduction in CCTα expression in adult liver and other tissues from Pcyt1a +/ − heterozygous mice. PtdCho biosynthesis measured by choline incorporation into isolated hepatocytes was not compromised in the Pcyt1a +/ − mice. Liver PtdCho mass was the same in Pcyt1a +/+ and Pcyt1a + / − adult animals, but lung PtdCho mass decreased in the heterozygous mice. These data show that CCTα expression is required for early embryonic development, but that a 50% reduction in enzyme activity has little detectable impact on the operation of the CDP-choline metabolic pathway in adult tissues.

scholarly journals Dependence of the adaptive capacity of liver mitochondria on preparation method

2020 ◽  
pp. 177-185
Author(s):  
H. Mazur ◽  
◽  
V. Merlavsky ◽  
B.O. Manko ◽  
V.V. Manko ◽  
...  
Keyword(s):  
Adaptive Capacity ◽  
Respiration Rate ◽  
Functional State ◽  
Liver Perfusion ◽  
Isolated Hepatocytes ◽  
Liver Mitochondria ◽  
Optimal Concentration ◽  
Maximal Rate

When conducting studies on isolated hepatocytes, it is important to obtain cells that retain the functional properties that are characteristic of the whole organ. Increased blood viscosity during liver perfusion, decreased perfusion pressure in blood vessels, and hence hypoxia, are among the factors that may affect the functional state of isolated hepatocytes. The functional state of cells can be estimated by the adaptive capacity of mitochondria, by inducing maximal respiration rate by uncoupling respiration and oxidative phosphorylation due to the addition of FCCP. The research aimed to investigate the adaptive capacity of mitochondria of isolated hepatocytes using in situ and in vitro liver perfusion. Hepatocytes were isolated by the two-staged Seglen method by in situ and in vitro liver perfusion. Isolated hepatocytes, after 15-minute incubation in the medium without addition or with respective oxidative substrate – glutamine, pyruvate, succinate, monomethyl succinate, α-ketoglutarate, dimethyl-α-ketoglutarate (at a concentration of 2 mM) or glucose (10 mM) – were added into the respiratory chamber and FCCP was added in increasing concentrations. It was established that at in situ liver perfusion maximal rate of uncoupled respiration and the optimal concentration of FCCP was higher than at in vitro liver perfusion. Addition of exogenous substrates to a medium increased the respiration rate of hepatocytes. Upon in situ liver perfusion maximal uncoupled respiration rate increased at all causes except glucose, and at in vitro liver perfusion – only when dimethyl-α-ketoglutarate, succinate and monomethyl succinate were used. The optimal concentration of FCCP at in vitro liver perfusion increased due to the addition of glutamine, pyruvate and monomethyl succinate to the medium, and at in situ liver perfusion – only upon glucose oxidation. In both perfusion methods, the highest maximal rate of uncoupled respiration is with the use of monomethyl succinate and the optimal FCCP concentration – upon pyruvate oxidation. Therefore, in situ liver perfusion is better method to obtain stable and metabolically active hepatocytes in support respiratory processes at a high level then in vitro perfusion.

In situ hybridization reveals co-expression of embryonic and adult alpha globin genes in the earliest murine erythrocyte progenitors

Development ◽  
1992 ◽  
Vol 116 (4) ◽  
pp. 1041-1049 ◽  
Author(s):  
A. Leder ◽  
A. Kuo ◽  
M.M. Shen ◽  
P. Leder
Keyword(s):  
In Situ Hybridization ◽  
Embryonic Development ◽  
Fetal Liver ◽  
Globin Gene ◽  
Yolk Sac ◽  
Globin Genes ◽  
Globin Mrna ◽  
Mature Adult ◽  
Alpha Globin

Murine erythropoiesis begins with the formation of primitive red blood cells in the blood islands of the embryonic yolk sac on day 7.5 of gestation. By analogy to human erythropoiesis, it has been thought that there is a gradual switch from the exclusive expression of the embryonic alpha-like globin (zeta) to the mature adult form (alpha) in these early mouse cells. We have used in situ hybridization to assess expression of these two globin genes during embryonic development. In contrast to what might have been expected, we find that there is simultaneous expression of both zeta and alpha genes from the very onset of erythropoiesis in the yolk sac. At no time could we detect expression of embryonic zeta globin mRNA without concomitant expression of adult alpha globin mRNA. Indeed, adult alpha transcripts exceed those of embryonic zeta in the earliest red cell precursors. Moreover, the pattern of hybridization reveals co-expression of both genes within the same cells. Even in the fetal liver, which supersedes the yolk sac as the major site of murine fetal erythropoiesis, there is a brief co-expression of zeta and alpha genes followed by the exclusive expression of the adult alpha genes. These data indicate an important difference in hematopoietic ontogeny between mouse and that of human, where zeta expression precedes that of alpha. In addition to resolving the embryonic expression of these globin genes, our results suggest that the embryonic alpha-like globin gene zeta may be physiologically redundant, even during the earliest stages of embryonic development.

scholarly journals Expression of the c-fos protooncogene by human and murine erythroblasts

Blood ◽  
1989 ◽  
Vol 74 (3) ◽  
pp. 947-951 ◽  
Author(s):  
JF Caubet ◽  
MT Mitjavila ◽  
A Dubart ◽  
D Roten ◽  
SC Weil ◽  
...  
Keyword(s):  
In Situ Hybridization ◽  
Bone Marrow Cells ◽  
Fetal Liver ◽  
Erythroid Differentiation ◽  
Northern Blotting ◽  
Hematopoietic Tissue ◽  
Double Labeling ◽  
Murine Bone Marrow ◽  
Marrow Cells

Abstract The expression of the c-fos protooncogene was investigated by in situ hybridization in normal murine bone marrow cells. A strong signal was found in murine marrow cells having the morphologic features of erythroblasts. This result was confirmed in human marrow cells using a double labeling technique (in situ hybridization and immunocytochemistry). A majority (70%) of the cells expressing c-fos mRNA were glycophorin A-positive. In contrast, granulocytic precursors (CD 15-positive) or monocytes and their precursors (CD 14-positive cells) did not significantly hybridize with the c-fos probe. In addition, c-fos mRNA (2.2Kb) was detected by Northern blotting in RNA extracted from homogeneous populations of erythroblasts obtained by immune panning from fetal liver and from adult blood BFU-E-derived colonies. Fos protein was also detected in erythroblasts by immunofluorescence. The high level of c-fos mRNA previously found in hematopoietic tissue should therefore be related to the transcription of the c-fos gene during terminal erythroid differentiation.

scholarly journals Changes in collagen and albumin mRNA in liver tissue of mice infected with Schistosoma mansoni as determined by in situ hybridization.

1983 ◽  
Vol 97 (4) ◽  
pp. 986-992 ◽  
Author(s):  
M A Saber ◽  
D A Shafritz ◽  
M A Zern
Keyword(s):  
In Situ Hybridization ◽  
Schistosoma Mansoni ◽  
Liver Tissue ◽  
Molecular Mechanisms ◽  
Type I Collagen ◽  
Primary Source ◽  
Isolated Hepatocytes ◽  
Type I ◽  
Albumin Mrna

We have employed in situ hybridization to evaluate the molecular mechanisms responsible for hypoalbuminemia and increased liver collagen content in murine schistosomiasis. Results were compared using a simplified method of hybridizing isolated hepatocytes from Schistosoma mansoni-infected and normal mouse liver with mouse albumin (pmalb-2) and chick pro-alpha 2(l) collagen (pCg45) probes. Whereas hepatocytes from infected mice showed significantly less albumin mRNA than hepatocytes from control, there were more grains of procollagen mRNA in hepatocytes from infected as compared with control liver. Hybridization of infected liver tissue sections with the collagen probe showed more grains per field in granulomas than in liver regions, whereas with the albumin probe there was more hybridization in liver tissue than in granulomas. These results suggest that in murine schistosomiasis a reduction in albumin mRNA sequence content may be associated with decreased albumin synthesis and ultimately leads to hypoalbuminemia. In addition, although the granuloma seems to be the primary source of type I collagen synthesis, hepatocytes are also capable of synthesizing collagen, especially under fibrogenic stimulation.

In Situ Study of Haemopoiesis in Human Fetal Liver

1989 ◽  
Vol 30 (4) ◽  
pp. 399-408 ◽  
Author(s):  
W. A. KAMPS ◽  
W. TIMENS ◽  
G. J. BOER ◽  
H. H. SPANJER ◽  
S. POPPEMA
Keyword(s):  
Fetal Liver ◽  
Human Fetal Liver ◽  
In Situ Study

Identification of a Developmentally-Restricted Hematopoietic Stem Cell That Gives Rise to Innate-like Lymphocytes

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4302-4302
Author(s):  
Anna E Beaudin ◽  
Scott W. Boyer ◽  
Gloria Hernandez ◽  
Camilla E Forsberg
Keyword(s):  
Stem Cell ◽  
Hematopoietic Stem Cell ◽  
Conflicts Of Interest ◽  
Fetal Liver ◽  
Lineage Tracing ◽  
Lymphoid Cells ◽  
Gfp Expression ◽  
Hematopoietic Stem

Abstract The generation of innate-like immune cells distinguishes fetal hematopoiesis from adult hematopoiesis, but the cellular mechanisms underlying differential cell production during development remain to be established. Specifically, whether differential lymphoid output arises as a consequence of discrete hematopoietic stem cell (HSC) populations present during development or whether the fetal/neonatal microenvironment is required for their production remains to be established. We recently established a Flk2/Flt3 lineage tracing mouse model wherein Flk2-driven expression of Cre recombinase results in the irreversible switching of a ubiquitous dual-color reporter from Tomato to GFP expression. Because the switch from Tom to GFP expression in this model involves an irreversible genetic excision of the Tomato gene, a GFP+ cell can never give rise to Tom+ progeny. Using this model, we have definitively demonstrated that all functional, adult HSC remain Tomato+ and therefore that all developmental precursors of adult HSC lack a history of Flk2 expression. In contrast, adoptive transfer experiments of Tom+ and GFP+ fetal liver Lin-cKit+Sca1+ (KLS) fractions demonstrated that both Tom+ and GFP+ fetal HSC support serial, long-term multilineage reconstitution (LTR) in irradiated adult recipients. We have therefore identified a novel, developmentally restricted HSC that supports long-term multilineage reconstitution upon transplantation into an adult recipient but does not normally persist into adulthood. Developmentally-restricted GFP+ HSC display greater lymphoid potential, and regenerated both innate-like B-1 lymphocytes and Vg3-expressing T lymphocytes to a greater extent than coexisting Tom+ FL and adult HSC. Interestingly, whereas developmental regulation of fetal-specific B-cell subsets appears to be regulated cell-instrinsically, as fetal HSC generated more innate-like B-cells than adult HSC even within an adult environment, T-cell development may be regulated both cell intrinsically and extrinsically, as both the cell-of-origin and the fetal microenvironment regulated the generation of innate-like T-cells. Our results provide direct evidence for a developmentally restricted HSC that gives rise to a layered immune system and describes a novel mechanism underlying the source of developmental hematopoietic waves. As early lymphoid cells play essential roles in establishing self-recognition and tolerance, these findings are critical for understanding the development of autoimmune diseases, allergies, and tolerance induction upon organ transplantation. Furthermore, by uncoupling self-renewal capacity in situ with that observed upon transplantation, our data suggests that transplantation- and/or irradiation-induced cues may allow for the engraftment of developmental HSC populations that do not normally persist in situ. As LTR upon transplantation has served as the prevailing definition of adult HSC origin during development, our data challenge the current conceptual framework of adult HSC origin. Disclosures No relevant conflicts of interest to declare.

scholarly journals The apparent Km of ammonia for carbamoyl phosphate synthetase (ammonia) in situ

1985 ◽  
Vol 229 (1) ◽  
pp. 205-211 ◽  
Author(s):  
N S Cohen ◽  
F S Kyan ◽  
S S Kyan ◽  
C W Cheung ◽  
L Raijman
Keyword(s):  
Isolated Hepatocytes ◽  
Perfused Liver ◽  
Carbamoyl Phosphate Synthetase ◽  
Carbamoyl Phosphate ◽  
Isolated Mitochondria ◽  
Regulation Of Synthesis

Experiments with carbamoyl phosphate synthetase (ammonia) in solution and in isolated mitochondria are reported which show the following. NH3 rather than NH4+ is the substrate of the enzyme. The apparent Km of NH3 for the purified enzyme is about 38 microM. The apparent Km for NH3 measured in intact isolated mitochondria is about 13 microM. This value was obtained for both coupled and uncoupled mitochondria and was unchanged when the rate of carbamoyl phosphate synthesis was increased 2-fold by incubating uncoupled mitochondria in the presence of 5 mM-N-acetylglutamate. According to the literature, the concentration of NH3 in liver is well below the measured apparent Km. On the basis of this and previous work we conclude that, quantitatively, changes in liver [NH3] and [ornithine] are likely to be the most important factors in the fast regulation of synthesis of carbamoyl phosphate and urea. This conclusion is consistent with all available evidence obtained with isolated mitochondria, isolated hepatocytes, perfused liver and whole animals.

Mutation in ankyrin repeats of the mouse Notch2 gene induces early embryonic lethality

Development ◽  
1999 ◽  
Vol 126 (15) ◽  
pp. 3415-3424 ◽  
Author(s):  
Y. Hamada ◽  
Y. Kadokawa ◽  
M. Okabe ◽  
M. Ikawa ◽  
J.R. Coleman ◽  
...  
Keyword(s):  
Fusion Protein ◽  
Cell Fate ◽  
Expression Patterns ◽  
Mutant Mice ◽  
Ankyrin Repeats ◽  
Early Embryonic Lethality ◽  
Homozygous Mutant ◽  
Beta Galactosidase ◽  
Deficient Mice

Notch family genes encode transmembrane proteins involved in cell-fate determination. Using gene targeting procedures, we disrupted the mouse Notch2 gene by replacing all but one of the ankyrin repeat sequences in the cytoplasmic domain with the E. coli (beta)-galactosidase gene. The mutant Notch2 gene encodes a 380 kDa Notch2-(beta)-gal fusion protein with (beta)-galactosidase activity. Notch2 homozygous mutant mice die prior to embryonic day 11.5, whereas heterozygotes show no apparent abnormalities and are fully viable. Analysis of Notch2 expression patterns, revealed by X-gal staining, demonstrated that the Notch2 gene is expressed in a wide variety of tissues including neuroepithelia, somites, optic vesicles, otic vesicles, and branchial arches, but not heart. Histological studies, including in situ nick end labeling procedures, showed earlier onset and higher incidence of apoptosis in homozygous mutant mice than in heterozygotes or wild type mice. Dying cells were particularly evident in neural tissues, where they were seen as early as embryonic day 9.5 in Notch2-deficient mice. Cells from Notch2 mutant mice attach and grow normally in culture, demonstrating that Notch2 deficiency does not interfere with cell proliferation and that expression of the Notch2-(beta)-gal fusion protein is not toxic per se. In contrast to Notch1-deficient mice, Notch2 mutant mice did not show disorganized somitogenesis, nor did they fail to properly regulate the expression of neurogenic genes such as Hes-5 or Mash1. In situ hybridization studies show no indication of altered Notch1 expression patterns in Notch2 mutant mice. The results indicate that Notch2 plays an essential role in postimplantation development in mice, probably in some aspect of cell specification and/or differentiation, and that the ankyrin repeats are indispensable for its function.

Differential expression of TGF beta 1, beta 2 and beta 3 genes during mouse embryogenesis

Development ◽  
1991 ◽  
Vol 111 (1) ◽  
pp. 117-130 ◽  
Author(s):  
P. Schmid ◽  
D. Cox ◽  
G. Bilbe ◽  
R. Maier ◽  
G.K. McMaster
Keyword(s):  
Fetal Liver ◽  
In Situ Hybridisation ◽  
Regulatory Elements ◽  
Northern Analysis ◽  
Tgf Beta ◽  
Mouse Embryogenesis ◽  
Root Sheath ◽  
Cell Layers ◽  
Beta 2

We have examined by Northern analysis and in situ hybridisation the expression of TGF beta 1, beta 2 and beta 3 during mouse embryogenesis. TGF beta 1 is expressed predominantly in the mesodermal components of the embryo e.g. the hematopoietic cells of both fetal liver and the hemopoietic islands of the yolk sac, the mesenchymal tissues of several internal organs and in ossifying bone tissues. The strongest TGF beta 2 signals were found in early facial mesenchyme and in some endodermal and ectodermal epithelial cell layers e.g., lung and cochlea epithelia. TGF beta 3 was strongest in prevertebral tissue, in some mesothelia and in lung epithelia. All three isoforms were expressed in bone tissues but showed distinct patterns of expression both spatially and temporally. In the root sheath of the whisker follicle, TGF beta 1, beta 2 and beta 3 were expressed simultaneously. We discuss the implication of these results in regard to known regulatory elements of the TGF beta genes and their receptors.

scholarly journals Direct nanoscale observations of the coupled dissolution of calcite and dolomite and the precipitation of gypsum

2014 ◽  
Vol 5 ◽  
pp. 1245-1253 ◽  
Author(s):  
Francesco Giancarlo Offeddu ◽  
Jordi Cama ◽  
Josep Maria Soler ◽  
Christine V Putnis
Keyword(s):  
Carbonate Minerals ◽  
Etch Pits ◽  
Equilibrium Conditions ◽  
Calcite Dissolution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Gypsum Precipitation ◽  
Induction Times ◽  
Rate Controlling Step

In-situ atomic force microscopy (AFM) experiments were performed to study the overall process of dissolution of common carbonate minerals (calcite and dolomite) and precipitation of gypsum in Na2SO4 and CaSO4 solutions with pH values ranging from 2 to 6 at room temperature (23 ± 1 °C). The dissolution of the carbonate minerals took place at the (104) cleavage surfaces in sulfate-rich solutions undersaturated with respect to gypsum, by the formation of characteristic rhombohedral-shaped etch pits. Rounding of the etch pit corners was observed as solutions approached close-to-equilibrium conditions with respect to calcite. The calculated dissolution rates of calcite at pH 4.8 and 5.6 agreed with the values reported in the literature. When using solutions previously equilibrated with respect to gypsum, gypsum precipitation coupled with calcite dissolution showed short gypsum nucleation induction times. The gypsum precipitate quickly coated the calcite surface, forming arrow-like forms parallel to the crystallographic orientations of the calcite etch pits. Gypsum precipitation coupled with dolomite dissolution was slower than that of calcite, indicating the dissolution rate to be the rate-controlling step. The resulting gypsum coating partially covered the surface during the experimental duration of a few hours.

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