scholarly journals Accumulation of malto-oligosaccharides in the syncytiotrophoblastic cells of first-trimester human placentas

1981 ◽  
Vol 200 (1) ◽  
pp. 93-98 ◽  
Author(s):  
S J Fisher ◽  
R A Laine
Keyword(s):  
Gel Filtration ◽  
First Trimester ◽  
Structural Elements ◽  
Trophoblastic Cells ◽  
Highly Active ◽  
A Cell ◽  
Liver Homogenates ◽  
High Concentrations ◽  
Very High

A cell-surface microvillar fraction that was isolated from the syncytiotrophoblastic cells of first-trimester human placentas was found to contain very high concentrations (890 +/- 32 microgram of hexose/mg of protein) of a class of low-molecular-weight oligosaccharides that were comprised entirely of glucose. T.l.c. and gel filtration showed that the saccharides contained from one to six glucose residues. The structures of the most prominent members of the series, a tetra- and a tri-saccharide, were determined. The anomeric configuration of the glucose residues was alpha, and methylation linkage analysis gave terminal and 4-linked hexose residues. These malto-oligosaccharides contained one reducing terminus per molecule, indicating that they were free and not bound to other structural elements of the cells. Within the placenta they appeared to be concentrated in the first-trimester trophoblastic cells, since crude membrane and particulate fractions isolated from either term trophoblastic cells or cultured placental fibroblasts did not contain detectable amounts of glucose oligomers. This series of oligosaccharides was similar to the products that are formed when glycogen is degraded by alpha-amylase in liver homogenates and may be indicative of a similar, highly active enzymic reaction closely associated with the brush border of the syncytiotrophoblastic cells of the first-trimester human placenta. Although the role of these oligosaccharides remains obscure they are probably involved in foetal metabolism.

scholarly journals The human complement system: assembly of the classical pathway C3 convertase

1980 ◽  
Vol 189 (1) ◽  
pp. 173-181 ◽  
Author(s):  
M A Kerr
Keyword(s):  
Direct Evidence ◽  
Gel Filtration ◽  
Fluid Phase ◽  
Classical Pathway ◽  
Human Complement ◽  
Stabilizing Effect ◽  
Excess Substrate ◽  
High Concentrations ◽  
Low Ionic Strength

The assembly of the classical pathway C3 convertase in the fluid phase has been studied. The enzyme is assembled from C2 and C4 on cleavage of these proteins by C1s. Once assembled, the enzyme activity decays rapidly. Kinetic evidence has been obtained that this decay is even more rapid than previously suggested (kdecay is 2.0 min-1 at 37 degrees C). As a result, optimal C3 convertase activity is only observed with high C1s levels, which result in rapid rates of cleavage of C2 and increased rates of formation of the C3 convertase. Using high concentrations of C1s at lower temperatures (22 degrees C) in the presence of excess substrate we have demonstrated kinetically that the enzyme comprises an equimolar complex of C4b and cleaved C2. We have obtained direct evidence from gel-filtration experiments for the role of C2a as the catalytic subunit of the enzyme. C2b appears to mediate the interaction between C4 (or C4b) and C2 at pH 8.5 and at low ionic strength where the interactions can easily be detected. It may therefore be important in the assembly of the enzyme, though it is not involved in the catalytic activity. The decay of the C3 convertase reflects the release of C2a from the C4b x (C2b) x C2a complex, and the stabilizing effect of iodine on the C3 convertase is therefore apparently one of stabilizing the C4b-C2z interaction, which is otherwise weak. C1s is not a part of the C3 convertase enzyme.

Familial Overexpression of β Antithrombin Caused by an Asn135Thr Substitution

Blood ◽  
1999 ◽  
Vol 93 (12) ◽  
pp. 4242-4247
Author(s):  
T.A. Bayston ◽  
A. Tripodi ◽  
P.M. Mannucci ◽  
E. Thompson ◽  
H. Ireland ◽  
...  
Keyword(s):  
Direct Sequencing ◽  
Consensus Sequence ◽  
Wild Type ◽  
Antithrombin Deficiency ◽  
Free System ◽  
Heparin Interaction ◽  
A Cell ◽  
Variant Protein ◽  
Very High

We have investigated the basis of antithrombin deficiency in an asymptomatic individual (and family) with borderline levels (≈70% antigen and activity) of antithrombin. Direct sequencing of amplified DNA showed a mutation in codon 135, AAC to ACC, predicting a heterozygous Asn135Thr substitution. This substitution alters the predicted consensus sequence for glycosylation, Asn-X-Ser, adjacent to the heparin interaction site of antithrombin. The antithrombin isolated from plasma of the proband by heparin-Sepharose chromatography contained amounts of β antithrombin (the very high affinity fraction) greatly increased (≈20% to 30% of total) above the trace levels found in normals. Expression of the residue 135 variant in both a cell-free system and COS-7 cells confirmed altered glycosylation arising as a consequence of the mutation. Wild-type and variant protein were translated and exported from COS-7 cells with apparently equal efficiency, in contrast to the reduced level of variant observed in plasma of the affected individual. This case represents a novel cause of antithrombin deficiency, removal of glycosylation concensus sequence, and highlights the potentially important role of β antithrombin in regulating coagulation.

Characteristics of a novel, anaerobic, mycoplasma-like bacterium from Ace Lake, Antarctica

1992 ◽  
Vol 4 (2) ◽  
pp. 155-162 ◽  
Author(s):  
P.D. Franzmann ◽  
M. Rohde
Keyword(s):  
Anaerobic Bacterium ◽  
Anaerobic Bacteria ◽  
Taxonomic Status ◽  
Optimum Temperature ◽  
Obligately Anaerobic ◽  
A Cell ◽  
Large Genome Size ◽  
High Concentrations ◽  
Pass Through

An obligately anaerobic bacterium that lacked a cell wall was isolated from the hypolimnion of Ace Lake, Antarctica. Cells were very pleomorphic, forming cocci, filaments up to 25 μm in length, and annular shapes. The organism was morphologically very similar to some members of the class Mollicutes which contains two genera of obligately anaerobic bacteria, Anaeroplasma and Asteroleplasma. Like members of the class, the isolate was resistant to high concentrations of penicillin (1000 Units ml-1). Similar to Anaeroplasma, the organism had a low DNA G+C content (29.3±0.4) and produced hydrogen, carbon dioxide, acetic acid, lactic acid and succinic acid from the fermentation of glucose. However, the taxonomic status of the strain remained unclear as, unlike members of the class Mollicutes, the isolate had a relatively large genome size (2.26±0.11 × 109 daltons), did not pass through 0.45 μm pore size filters, and did not form typical mycoplasma-like colonies. The organism was psychrophilic with an optimum temperature for growth between 12°C and 13°C. A phenotypic description of the organism is given and the ecological role of the organism is inferred from its phenotype and the characteristics of its Antarctic habitat.

scholarly journals Physical and Chemical Characteristics of a Mediterranean Coastal Microenvironment: The "Salty Lake" of Aghios Nikolaos (Crete, Greece)

2013 ◽  
Vol 2 (2) ◽  
pp. 167-178
Keyword(s):  
Coastal Waters ◽  
Marine Ecosystem ◽  
Anthropogenic Pollutants ◽  
High Concentrations ◽  
Lake Waters ◽  
Physical And Chemical ◽  
The Impact ◽  
Very High ◽  
Production Of Ammonia

The present paper examines a small and deep (53 m) salty lake, as well as the adjacent harbor of Aghios Nikolaos (Crete). The survey was carried out in 1996. Physicochemical parameters indicated that the main characteristics of the system are the inflow of karstic water from underwater springs inside the lake and the permanent anoxic conditions prevailing in its deeper part, below the thermocline. Nutrient concentrations are very high throughout the water column of the lake. Ammonia is the main source of nitrogen in the summer, particularly below the thermocline, whereas nitrates have high concentrations during spring and autumn. The high levels of these nutrients in the adjacent to the lake harbor and coastal waters indicate clearly the impact of the lake to the marine ecosystem. Anthropogenic pollutants, such as aromatic hydrocarbons, show high concentrations above thermocline, at 5-10 m depths during all samplings. However no particular point source was identified. The presence of hydrocarbons contributes to ineffective oxygenation of the lake waters and facilitates the development of anoxia and the production of ammonia. The PAH concentrations at the sampling stations outside the lake are typical of marine environments, with relatively small oil-derived inputs, indicating the complex role of the system as a source and/or as a trap of PAHs.

Familial Overexpression of β Antithrombin Caused by an Asn135Thr Substitution

Blood ◽  
1999 ◽  
Vol 93 (12) ◽  
pp. 4242-4247 ◽  
Author(s):  
T.A. Bayston ◽  
A. Tripodi ◽  
P.M. Mannucci ◽  
E. Thompson ◽  
H. Ireland ◽  
...  
Keyword(s):  
Direct Sequencing ◽  
Consensus Sequence ◽  
Wild Type ◽  
Antithrombin Deficiency ◽  
Free System ◽  
Heparin Interaction ◽  
A Cell ◽  
Variant Protein ◽  
Very High

Abstract We have investigated the basis of antithrombin deficiency in an asymptomatic individual (and family) with borderline levels (≈70% antigen and activity) of antithrombin. Direct sequencing of amplified DNA showed a mutation in codon 135, AAC to ACC, predicting a heterozygous Asn135Thr substitution. This substitution alters the predicted consensus sequence for glycosylation, Asn-X-Ser, adjacent to the heparin interaction site of antithrombin. The antithrombin isolated from plasma of the proband by heparin-Sepharose chromatography contained amounts of β antithrombin (the very high affinity fraction) greatly increased (≈20% to 30% of total) above the trace levels found in normals. Expression of the residue 135 variant in both a cell-free system and COS-7 cells confirmed altered glycosylation arising as a consequence of the mutation. Wild-type and variant protein were translated and exported from COS-7 cells with apparently equal efficiency, in contrast to the reduced level of variant observed in plasma of the affected individual. This case represents a novel cause of antithrombin deficiency, removal of glycosylation concensus sequence, and highlights the potentially important role of β antithrombin in regulating coagulation.

scholarly journals The Preeclamptic Environment Promotes the Activation of Transcription Factor Kappa B by P53/RSK1 Complex in a HTR8/SVneo Trophoblastic Cell Line

2021 ◽  
Vol 22 (19) ◽  
pp. 10200
Author(s):  
Agata Sakowicz ◽  
Michalina Bralewska ◽  
Tadeusz Pietrucha ◽  
Francesc Figueras ◽  
Dominika E. Habrowska-Górczyńska ◽  
...  
Keyword(s):  
Transcription Factor ◽  
Cell Line ◽  
Critical Role ◽  
First Trimester ◽  
Trophoblastic Cell ◽  
Trophoblastic Cells ◽  
Hypoxic Conditions ◽  
Activation Of Transcription ◽  
Placental Cells

Preeclampsia is a pregnancy disorder associated with shallow placentation, forcing placental cells to live in hypoxic conditions. This activates the transcription factor kappa B (NFκB) in maternal and placental cells. Although the role of NFκB in preeclampsia is well documented, its mechanism of activation in trophoblastic cells has been never studied. This study investigates the mechanism of NFκB activation in a first trimester trophoblastic cell line (HTR8/SVneo) stimulated by a medium containing serum from preeclamptic (PE) or normotensive (C) women in hypoxic (2% O2) or normoxic (8% O2) conditions. The results indicate that in HTR8/SVneo cells, the most widely studied NFκB pathways, i.e., canonical, non-canonical and atypical, are downregulated in environment PE 2% O2 in comparison to C 8% O2. Therefore, other pathways may be responsible for NFκB activation. One such pathway depends on the activation of NFκB by the p53/RSK1 complex through its phosphorylation at Serine 536 (pNFκB Ser536). The data generated by our study show that inhibition of the p53/RSK1 pathway by p53-targeted siRNA results in a depletion of pNFκB Ser536 in the nucleus, but only in cells incubated with PE serum at 2% O2. Thus, the p53/RSK1 complex might play a critical role in the activation of NFκB in trophoblastic cells and preeclamptic placentas.

scholarly journals Role of Misoprostol in Missed Abortion

2013 ◽  
Vol 26 (2) ◽  
pp. 92-99
Author(s):  
KN Nahar ◽  
SB Chowdhury ◽  
Shayela Shamim ◽  
Begum Nasrin ◽  
Fawzia Hossain ◽  
...  
Keyword(s):  
Cardiac Activity ◽  
Expectant Management ◽  
First Trimester ◽  
Uterine Perforation ◽  
Missed Abortion ◽  
Gestational Sac ◽  
Vaginal Misoprostol ◽  
Very High

Spontaneous abortion or miscarriage is the spontaneous end of a pregnancy at a stage where  the embryo or fetus is incapable of surviving independently, generally defined in humans at  prior to 20 weeks of gestation, but in our country before 28 weeks of gestation. Nearly 20% of  all confirmed pregnancies end in abortion. The incidence of this type of abortion is very high  during first trimester and decreases with increasing gestational age. Of many types of abortion, missed abortion occurs when the embryo or foetus has died, but a miscarriage has not yet  occurred. The retention of a fetus known to be dead for >4 weeks. The cervix is closed and   there is no or only slight bleeding. Ultrasound examination shows an empty gestational sac or  an embryo/fetus without cardiac activity. Surgical evacuation is the most common method of  treatment of missed abortion.It is considered to be safe but carries some risk of complications  related to anaesthesia and of surgical complications such as uterine perforation, cervical trauma, intrauterine adhesions and infections. Expectant management and medical treatment  are the two other ways of treatment of missed abortion. Based on a review of the published  literature, a single dose of 800?g vaginal misoprostol may be offered as an effective, safe and acceptable alternative to the traditional surgical treatment for this indication in the first trimester. Alternatively, 800?g misoprostol can be administered sublingually. Treatment may be repeated  twice with a 3-4 hour interval for maximum three doses can be given orally or sublingually. Where as, vaginally, dose can be repeated 6-8 hourly for three doses. For the rest, 12-28 weeks of missed abortion,400?g of misoprostol every 4 hours until expulsion. Majority of  cases have the expulsion within 48 hours. After administration of misoprostol, hospitalization  is not necessary and the time of expulsion varies considerably. Bleeding may last for more than 14 days with additional days of light bleeding or spotting. The woman should be advised  to contact a provider in case of heavy bleeding or signs of infection. A follow up is recommended  after 1 to 2 weeks.DOI: http://dx.doi.org/10.3329/bjog.v26i2.13787Bangladesh J Obstet Gynaecol, 2011; Vol. 26(2) : 92-99 

scholarly journals Glycyl-l-leucine hydrolase, a versatile ‘master’ dipeptidase from monkey small intestine

1973 ◽  
Vol 135 (4) ◽  
pp. 609-615 ◽  
Author(s):  
Manjusri Das ◽  
A. N. Radhakrishnan
Keyword(s):  
Molecular Weight ◽  
Chromatographic Method ◽  
Gel Filtration ◽  
Peptide Transport ◽  
Small Intestinal Mucosa ◽  
Highly Active ◽  
Structural Types ◽  
Wide Range ◽  
Small Intestinal

1. A highly active and electrophoretically homogeneous dipeptidase was purified from the soluble extracts of monkey small-intestinal mucosa. 2. By gel-filtration studies the molecular weight of the enzyme was found to be 107000. It is composed of two identical, subunits of molecular weight 54000. 3. A paper-chromatographic method of dipeptidase assay was developed to overcome some of the difficulties encountered in the generally used spectrophotometric procedure. By using this method, the Km and k0 values of a few substrates were determined. 4. The substrate specificity of the enzyme was investigated in great detail with substrates of a wide range of possible structural types. The enzyme hydrolyses a very large proportion of the range of dipeptides tested. This enzyme, which exhibits such a wide range of action, has been termed the ‘master’ dipeptidase of the intestine. Glycylglycine, glycyl-l-proline, glycyl-l-histidine, l-prolylglycine and some of the arginine- and aspartic acid-containing dipeptides were not substrates and are possibly hydrolysed by other peptidases. These results therefore suggest that in the intestine the number of dipeptidases is rather limited. 5. In the light of these findings, the implications on the role of dipeptidases in intestinal peptide transport are discussed.

scholarly journals Anaphase-promoting complex/cyclosome regulates RdDM activity by degrading DMS3 in Arabidopsis

2019 ◽  
Vol 116 (9) ◽  
pp. 3899-3908 ◽  
Author(s):  
Songxiao Zhong ◽  
Yifeng Xu ◽  
Chaoyi Yu ◽  
Xiaotuo Zhang ◽  
Lei Li ◽  
...  
Keyword(s):  
Gel Filtration ◽  
Dependent Manner ◽  
Anaphase Promoting Complex ◽  
Binding Assays ◽  
Protein Levels ◽  
Pol V ◽  
Dna Polymerase V ◽  
A Cell ◽  
Cycle Dependent

During RNA-directed DNA methylation (RdDM), the DDR complex, composed of DRD1, DMS3, and RDM1, is responsible for recruiting DNA polymerase V (Pol V) to silence transposable elements (TEs) in plants. However, how the DDR complex is regulated remains unexplored. Here, we show that the anaphase-promoting complex/cyclosome (APC/C) regulates the assembly of the DDR complex by targeting DMS3 for degradation. We found that a substantial set of RdDM loci was commonly de-repressed in apc/c and pol v mutants, and that the defects in RdDM activity resulted from up-regulated DMS3 protein levels, which finally caused reduced Pol V recruitment. DMS3 was ubiquitinated by APC/C for degradation in a D box-dependent manner. Competitive binding assays and gel filtration analyses showed that a proper level of DMS3 is critical for the assembly of the DDR complex. Consistent with the importance of the level of DMS3, overaccumulation of DMS3 caused defective RdDM activity, phenocopying the apc/c and dms3 mutants. Moreover, DMS3 is expressed in a cell cycle-dependent manner. Collectively, these findings provide direct evidence as to how the assembly of the DDR complex is regulated and uncover a safeguarding role of APC/C in the regulation of RdDM activity.

scholarly journals The separation and distribution of simple and condensed leucoanthocyanins of the tea plant (Camellia sinensis L.)

1969 ◽  
Vol 113 (5) ◽  
pp. 757-763 ◽  
Author(s):  
G. I. Forrest ◽  
D S Bendall
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Inverse Correlation ◽  
Tea Plant ◽  
Degree Of Polymerization ◽  
Monomer Ratio ◽  
Lower Mobility ◽  
High Concentrations ◽  
Root Tissues ◽  
Very High

1. Leucoanthocyanin monomers of high mobilities in aqueous solvents on thinlayer chromatograms, assumed to be structurally simple, were characteristic of mature bulky tissues, whereas members of lower mobility were confined to young vegetative and floral tissues. 2. Flavylogens were separated by gel filtration on Sephadex columns into monomeric, oligomeric and polymeric fractions. 3. The polymeric fraction from young brown stems was heterogeneous, one-half having a molecular weight of about 3400, one-third a molecular weight between 3600 and 17000, and the remainder a molecular weight of over 17000. 4. Leaves had low flavylogen concentrations; only monomers were present. Stem tissues were rich in polymers, which increased with the age of the young stem and decreased inwards through the wood. The maximal flavylogen concentrations were in the phloem and cambium from mature stems, where all three fractions were richly present. The periderm tissue and, to a lesser extent, the seed coat were characterized by a very high polymer/monomer ratio, exhibiting a much higher degree of polymerization than the wood. Root tissues contained high concentrations of monomers. 5. In general, there was an inverse correlation between the extent of polymerization and the complexity of the monomers present. 6. The results are in favour of the thesis that the function of the flavanols is, after polymerization to condensed tannins, to impregnate dead structural tissues and thereby to protect them from infection and decay.

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