Distribution of the head-activating substance in hydra and its localization in membranous particles in nerve cells

Development ◽  
1973 ◽  
Vol 29 (1) ◽  
pp. 39-52
Author(s):  
H. Schaller ◽  
A. Gierer
Keyword(s):  
Molecular Weight ◽  
Specific Activity ◽  
Nerve Cells ◽  
Low Molecular Weight ◽  
Basal Region ◽  
Bud Formation ◽  
Minor Portion ◽  
A Minor ◽  
Bud Initiation ◽  
Head Regeneration

The low-molecular-weight substance activating head and bud formation in hydra is shown to occur in the animal as a gradient decreasing from the hypostomal to the basal region. The concentration of head-activating substance increases during head regeneration and during bud initiation. Most of the low-molecular-weight head-activating substance is present in the animal in a structure-bound form. More than 90% was sedimentable; 70% was recovered in a highly purified fraction consisting of membranous particles of ∼ 1200 Å diameter. This implies that in the animal only a minor portion of the total activating activity is freely diffusible, i.e. present in the low-molecular-weight form. The head-activating substance is mainly produced by and/or stored in nerve cells or a subgroup of the nerve cells. Nerve cells were enriched tenfold in a fraction containing most of the head-activating substance in a more than 10 times higher specific activity than in the animal. In addition, it is shown that only the nerve cells are positively correlated with the distribution of head-activating activity both with regard to localization within the animal as to time sequence of appearance during head regeneration and bud formation.

scholarly journals Utilization of low molecular weight organic compounds by the filterable fraction of a lotic microbiome

2020 ◽  
Author(s):  
Lydia-Ann J Ghuneim ◽  
Marco A Distaso ◽  
Tatyana N Chernikova ◽  
Rafael Bargiela ◽  
Evgenii A Lunev ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Community Dynamics ◽  
Lag Phase ◽  
Minor Role ◽  
Low Molecular Weight ◽  
Freshwater Systems ◽  
North Wales ◽  
Clusters Of Orthologous Groups ◽  
A Minor ◽  
Substrate Addition

Abstract Filterable microorganisms participate in dissolved organic carbon (DOC) cycling in freshwater systems, however their exact functional role remains unknown. We determined taxonomic identity and community dynamics of prokaryotic microbiomes in the 0.22 µm-filtered fraction and unfiltered freshwater from the Conwy River (North Wales, UK) in microcosms and, using targeted metabolomics and 14C-labelling, examined their role in utilization of amino acids, organic acids, and sugars spiked at environmentally-relevant (nanomolar) concentrations. To identify changes in community structure, we used 16S rRNA amplicon and shotgun sequencing. Unlike the unfiltered water samples where the consumption of DOC was rapid, the filtered fraction showed a 3-days lag phase before the consumption started. Analysis of functional categories of clusters of orthologous groups of proteins (COGs) showed COGs associated with energy production increased in numbers in both fractions with substrate addition. The filtered fraction utilized low-molecular-weight (LMW) DOC at much slower rates than the whole community. Addition of nanomolar concentrations of LMW DOC did not measurably influence the composition of the microbial community nor the rate of consumption across all substrate types in either fraction. We conclude that due to their low activity, filterable microorganisms play a minor role in LMW DOC processing within short residence time of lotic freshwater systems.

scholarly journals The interrelations between high- and low-molecular-weight forms of normal and mutant (Krabbe-disease) galactocerebrosidase

1980 ◽  
Vol 189 (1) ◽  
pp. 9-15 ◽  
Author(s):  
Yoav Ben-Yoseph ◽  
Melinda Hungerford ◽  
Henry L. Nadler
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Specific Activity ◽  
Polyacrylamide Gel Electrophoresis ◽  
Active Form ◽  
Sodium Dodecyl ◽  
Krabbe Disease ◽  
Low Molecular Weight ◽  
Molecular Weight Form

Galactocerebrosidase (β-d-galactosyl-N-acylsphingosine galactohydrolase; EC 3.2.1.46) activity of brain and liver preparations from normal individuals and patients with Krabbe disease (globoid-cell leukodystrophy) have been separated by gel filtration into four different molecular-weight forms. The apparent mol.wts. were 760000±34000 and 121000±10000 for the high- and low-molecular-weight forms (peaks I and IV respectively) and 499000±22000 (mean±s.d.) and 256000±12000 for the intermediate forms (peaks II and III respectively). On examination by sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, the high- and low-molecular-weight forms revealed a single protein band with a similar mobility corresponding to a mol.wt. of about 125000. Antigenic identity was demonstrated between the various molecular-weight forms of the normal and the mutant galactocerebrosidases by using antisera against either the high- or the low-molecular-weight enzymes. The high-molecular-weight form of galactocerebrosidase was found to possess higher specific activity toward natural substrates when compared with the low-molecular-weight form. It is suggested that the high-molecular-weight enzyme is the active form in vivo and an aggregation process that proceeds from a monomer (mol.wt. approx. 125000) to a dimer (mol.wt. approx. 250000) and from the dimer to either a tetramer (mol.wt. approx. 500000) or a hexamer (mol.wt. approx. 750000) takes place in normal as well as in Krabbe-disease tissues.

Immunoaffinity Chromatography of Canine High-Molecular-Weight Renin: Partial Purification and Characterization

1983 ◽  
Vol 65 (2) ◽  
pp. 117-120 ◽  
Author(s):  
Fumihiko Ikemoto ◽  
Victor J. Dzau ◽  
Edgar Haber ◽  
Kazuo Takaori ◽  
Kenjiro Yamamoto
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Specific Activity ◽  
Immunoaffinity Chromatography ◽  
Partial Purification ◽  
Low Molecular Weight ◽  
Specific Method ◽  
Disulphide Bonds ◽  
Binding Substance ◽  
Molecular Weight Form

1. Canine high-molecular-weight renin (mol. wt. 60 000) is believed to be a complex of renin (low-molecular-weight form, mol. wt. 40 000) and renin-binding substance. The immunocross-reactivity of high-molecular-weight renin and low-molecular-weight renin was demonstrated by using antibodies specific to low-molecular-weight renin. 2. Immunoaffinity chromatography with renin-specific antibodies coupled to Sepharose provided a simple and specific method for isolation of high-molecular-weight renin. High-molecular-weight renin with a specific activity of 137 600 ng of ANG I h−1 mg−1 of protein (19.6 Goldblatt units/mg of protein) was obtained. 3. This high-molecular-weight renin was stable in dithiothreitol (25 mmol/l), suggesting that disulphide bonds may not be involved in the binding mechanism between low-molecular-weight renin and renin-binding substance. 4. However, exposure to low pH (3.0) resulted in conversion of high-molecular-weight renin into the low-molecular-weight form.

scholarly journals Isolation and characterization of a low-molecular-weight substance activating head and bud formation in hydra

Development ◽  
1973 ◽  
Vol 29 (1) ◽  
pp. 27-38
Author(s):  
H. Chica Schaller
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight ◽  
Bud Formation ◽  
Isolation And Characterization ◽  
Crude Extracts ◽  
Head Formation ◽  
Weight Substance

From crude extracts of hydra, a substance activating head formation was isolated and enriched at least 100000-fold. The molecular weight was determined to be approximately 900. Sensitivity against proteases suggests that it is a peptide. The substance acts at a concentration equivalent to the extract of 1 hydra per ml or at a concentration of less than 10 10M. In its highly purified form the substance activates head and bud formation.

Mechanisms for altering phosphorus sorption characteristics induced by low-molecular-weight organic acids

2016 ◽  
Vol 96 (3) ◽  
pp. 289-298 ◽  
Author(s):  
Yongzhuang Wang ◽  
Joann K. Whalen ◽  
Xin Chen ◽  
Yanhong Cao ◽  
Bin Huang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Organic Acids ◽  
Low Molecular Weight ◽  
Minor Effect ◽  
Phosphorus Sorption ◽  
Sorption Data ◽  
P Fractionation ◽  
Soil P ◽  
P Sorption ◽  
A Minor

Exudation of low-molecular-weight organic acids (LMWOAs) from plant roots enhances phosphorus (P) acquisition from soil, either by dissolving P fixed in secondary minerals or by reducing P sorption to organo-minerals. How LMWOAs may modify P sorption in soils with contrasting pH is not well understood, much less the mechanisms involved. The effects of three common LMWOAs (oxalic, citric, and malic acids) on P sorption in calcareous, neutral, and acidic soils were studied in batch experiments, followed by sequential P fractionation to elucidate the mechanisms whereby LMWOAs alter P sorption. The sorption data of the three soils fitted better to the Freundlich equation (r2 = 0.325–0.994, P < 0.05) than the Langmuir and linear equations. Oxalic, citric, and malic acids at 10 mmol kg−1 soil decreased the Freundlich P sorption parameters Kf and n, which represent P sorption capacity and energy, due to the fact that LMWOAs reduced P sorption in NaHCO3-Pi (soil soluble and exchangeable Pi, 23.8–30.9%) and NaOH-Pi (Fe-Pi and Al-Pi, 21.6–54.2%) fractions of the three soils. Comparing acidified P-LMWOAs solutions with the pH-adjusted P-LMWOAs solutions (pH = 7) had a minor effect on P sorption. Our results indicated that the reduction in soil P sorption was due to ligand exchange and chelation of LMWOAs with Fe and Al minerals, and the acid strength of LMWOAs had a minor effect on P sorption in calcareous, neutral, and acid soils.

Construction, Expression, and Characterization of a Recombinant Annexin B1-Low Molecular Weight Urokinase Chimera in Escherichia coli

2004 ◽  
Vol 36 (3) ◽  
pp. 184-190 ◽  
Author(s):  
Hong-Li Yan ◽  
Wei-Ting Wang ◽  
Yan He ◽  
Zhuan-You Zhao ◽  
Yuan-Jian Gao ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Specific Activity ◽  
Anticoagulant Activity ◽  
Membrane Binding ◽  
Low Molecular Weight ◽  
Single Chain ◽  
T7 Promoter ◽  
Overlap Extension ◽  
Annexin B1

Abstract To produce a thrombi-targeting plasminogen activator, low molecular weight single-chain urokinase gene (scuPA32k) was spliced with the full-length cDNA of annexin B1 gene (anxB1) by overlap extension method. The fused gene anxB1scuPA was ligated into pET28a vector, transformed into E. coli BL21-RIL, and then induced to express under the control of T7 promoter. The AnxB1ScuPA protein expressed amounted to 22% of the total bacterial proteins. The product was refolded, and then purified by using DEAE Sepharose fast flow ion-exchange column and Superdex S-200 gel-filtration column. HPLC analysis revealed that the final purity is about 95%. The specific activity of AnxB1ScuPA, measured as amidolytic activity, reached 100,000 IU/mg. It had a similar S2444 catalytic efficiency (kcat/Km) to ScuPA32k, and also showed high activated-platelet membrane-binding activity and anticoagulant activity, indicating that the chimera fully retained the components of enzymatic and membrane-binding activities of the parent molecules. In vivo test revealed that, the dogs administered with AnxB1ScuPA had less reperfusion time, higher reperfusion ratio, and less bleeding effects than those with urokinase. These findings indicated that AnxB1ScuPA might have advantages over current available thrombolytic agents.

Antithrombotic Properties Of Low Molecular Weight Heparin Fractions From Porcine Mucosal Heparin

1981 ◽  
Author(s):  
J Choay ◽  
Jean C Lormeau ◽  
Harry L Messmore ◽  
Jawed Fareed ◽  
J Stulc ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Prothrombin Complex Concentrate ◽  
Specific Activity ◽  
Weight Fraction ◽  
Low Molecular Weight ◽  
Prothrombin Complex Concentrates ◽  
Heparin Fractions ◽  
Russell’S Viper ◽  
Molecular Weight Fractions

A previous report from our laboratories has described the extraction and physicochemical properties of a low molecular weight fraction (mol wt 4-8 × 103 daltons) from porcine mucosal heparin (Choay et. al. thrombosis Res 18, 573, 1980). Beside exhibiting a strong anti Xa (>250 u/mg) activity, this product possessed strong antithrombotic properties in a modified rabbit stasis thrombosis model. At a 125 anti Xa u/kg it protected the thrombotic effects of activated prothrombin complex concentrate (20 u/kg) and Prothrombin Complex Concentrate/Russell’s Viper Venom challenge in both the pretreatment and post-treatment regiments. At 1250 anti Xa u/kg SC it also showed antithrombotic effects for various periods. We have also obtained another low molecular weight fraction from porcine mucosal heparin by controlled depolymerization with nitrous acid. This product possessed saccharides with molecular weight ranging 3-6 × 103 daltons and exhibited a specific activity of >200 anti Xa u/mg. At a 125 anti Xa u/kg this product also showed antithrombotic activity against the thrombotic effects of activated prothrombin complex concentrates, prothrombin complex concentrates and Russell’s Viper Venom. In contrast to these two low molecular weight fractions porcine mucosal heparin in identical anti Xa units failed to produce protection against the thrombogenic stimuli. Our studies suggest that low molecular weight heparin fractions with strong anti Xa and antithrombotic activities can be obtained by chemical depolymerization. Furthermore, their biologic properties are found to be similar to the naturally occuring low molecular weight fractions present in native porcine mucosal heparin.

scholarly journals Low molecular weight nonheme iron and a highly labeled heme pool in the reticulocyte

Blood ◽  
1980 ◽  
Vol 56 (3) ◽  
pp. 564-566 ◽  
Author(s):  
S Pollack ◽  
T Campana
Keyword(s):  
Molecular Weight ◽  
Guinea Pig ◽  
Specific Activity ◽  
Chelating Agent ◽  
Nonheme Iron ◽  
Low Molecular Weight ◽  
Alpha Chain ◽  
Molecular Weight Peak ◽  
First Time

Abstract The ligands that bind iron and heme in reticulocyte and may regulate their distribution are not known. Guinea pig reticulocyte hemolysates were labeled with 59Fe and filtered through molecular weight sieving columns. 59Fe-containing peaks of ferritin, transferrin, and hemoglobin were identified, as well as a low molecular weight peak containing predominantly nonheme iron, and a 17,000 mol wt heme containing peak with a specific activity (59Fe/heme) 20-fold greater than hemoglobin. We note that the low molecular weight peak, the existence of which has been postulated, has been identified for the first time without the addition of a chelating agent. We speculate that the 17,000 mol wt peak is an alpha-chain pool.

scholarly journals Low molecular weight nonheme iron and a highly labeled heme pool in the reticulocyte

Blood ◽  
1980 ◽  
Vol 56 (3) ◽  
pp. 564-566
Author(s):  
S Pollack ◽  
T Campana
Keyword(s):  
Molecular Weight ◽  
Guinea Pig ◽  
Specific Activity ◽  
Chelating Agent ◽  
Nonheme Iron ◽  
Low Molecular Weight ◽  
Alpha Chain ◽  
Molecular Weight Peak ◽  
First Time

The ligands that bind iron and heme in reticulocyte and may regulate their distribution are not known. Guinea pig reticulocyte hemolysates were labeled with 59Fe and filtered through molecular weight sieving columns. 59Fe-containing peaks of ferritin, transferrin, and hemoglobin were identified, as well as a low molecular weight peak containing predominantly nonheme iron, and a 17,000 mol wt heme containing peak with a specific activity (59Fe/heme) 20-fold greater than hemoglobin. We note that the low molecular weight peak, the existence of which has been postulated, has been identified for the first time without the addition of a chelating agent. We speculate that the 17,000 mol wt peak is an alpha-chain pool.

Radioiodination of Alginate via Covalently-Bound Tyrosinamide Allows Monitoring of its Fate In Vivo

1995 ◽  
Vol 10 (1) ◽  
pp. 4-13 ◽  
Author(s):  
Aymen Al-Shamkhani ◽  
Ruth Duncan
Keyword(s):  
Molecular Weight ◽  
Intraperitoneal Injection ◽  
Specific Activity ◽  
Subcutaneous Administration ◽  
High Specific Activity ◽  
Weight Fraction ◽  
Low Molecular Weight ◽  
Blood Compartment ◽  
Almost All

Tb monitor the fate of alginate following systemic administration, a method was developed that allowed the covalent incorporation of approximately 1 mol% tyrosinamide. The product could be radioiodinated to a high specific activity, and was subsequently stable on storage at 4°C for 30 days, with very little (c 1%) free [125I] iodide released over that period. Twenty-four hours following intravenous administration, the low molecular weight fraction (<48,000) of the injected polymer was excreted in the urine while the larger polymer fraction remained in the circulation and did not readily accumulate in any of the tissues. Almost all of the dose administered by intraperitoneal injection was transferred from the peritoneal cavity to the blood compartment within 24 h, with the low molecular weight fraction of the polymer excreted in the urine. Following subcutaneous administration, the majority (-70%) of the injected dose was retained at the site of injection at 24 h.

Sign in / Sign up

Export Citation Format

Share Document