Biological Availability of Low Versus High Molecular Weight Reactive Phosphorus

1978 ◽  
Vol 35 (12) ◽  
pp. 1639-1643 ◽  
Author(s):  
Hans W. Paerl ◽  
Malcolm T. Downes
Keyword(s):  
Molecular Weight ◽  
New Zealand ◽  
Key Words ◽  
High Molecular Weight ◽  
Growth Response ◽  
Growth Yields ◽  
Good Growth ◽  
Biological Availability ◽  
Culture Filtrates ◽  
Reactive Phosphorus

When equivalent concentrations of reactive high molecular weight phosphorus (RHMW-P > 5000) and free orthophosphate (PO4-P) from Lake Tutaeinanga, New Zealand, were added to P-starved Chlorella cultures, free PO4 showed a faster growth response within 48 h than RHMW-P. Algal preference for PO4 over RHMW-P could also be shown by (32P)PO4 turnover experiments. After 96 h both fractions showed good growth yields. Analyses on culture filtrates indicated that all forms of reactive P had been removed. This demonstrates that RHMW-P, which reacts with "reactive P" reagents, can eventually be utilized. Key words: reactive phosphorus, orthophosphate, algae, Chlorella, growth, bioassay

Distribution and Biological Availability of Reactive High Molecular Weight Phosphorus in Natural Waters in New Zealand

1980 ◽  
Vol 37 (4) ◽  
pp. 664-669 ◽  
Author(s):  
E. White ◽  
G. Payne
Keyword(s):  
Molecular Weight ◽  
New Zealand ◽  
High Molecular Weight ◽  
Natural Waters ◽  
Phosphorus Uptake ◽  
Algal Growth ◽  
Gel Chromatography ◽  
Growth Responses ◽  
Eutrophic Lakes ◽  
Reactive Phosphorus

Eutrophic lakes and many streams on the central volcanic plateau of the North Island, New Zealand, contain dissolved chemically reactive phosphorus which is not orthophosphate. Sephadex gel (G25-150) chromatograms reveal that one reactive component is of high molecular weight (MW > 5000) while a second component elutes in the same way as phosphate-phosphorus (PO4-P). The reactive high molecular weight phosphorus (RHMW-P) in streams generally forms only a small proportion of the dissolved reactive phosphorus (DRP). In some eutrophic lakes the proportion of RHMW-P in the DRP is high (70–80%). Each lake may have a characteristic distribution of the two forms of reactive phosphorus. In summer where DRP concentrations are low (<2 mg∙m−3) in lake surface waters, PO4-P seems to dominate over RHMW-P which is consistent with long 32PO4 turnover times which are found in many of the central volcanic plateau lakes. Algal growth responses to phosphorus uptake were similar for PO4-P and RHMW-P, but not all of the RHMW-P was taken up by Chlorella in bioassays. The proportion of the RHMW-P taken up by Chlorella was different for each lake examined, posing problems in relating DRP concentrations to algal growth responses in lakes.Key words: reactive phosphorus, phosphate-phosphorus, algae, Chlorella, growth, bioassay, freshwater analysis, molybdenum blue method, Sephadex gel chromatography

Separation of Two Dissolved Reactive Phosphorus Fractions in Lakewater

1978 ◽  
Vol 35 (12) ◽  
pp. 1636-1639 ◽  
Author(s):  
Malcolm T. Downes ◽  
Hans W. Paerl
Keyword(s):  
Molecular Weight ◽  
Key Words ◽  
High Molecular Weight ◽  
Gel Filtration ◽  
Molybdenum Blue ◽  
Dissolved Reactive Phosphorus ◽  
P Fraction ◽  
Analytical Reagents ◽  
Reactive Phosphorus ◽  
Hydrolysis Of

A method for the separation of two dissolved reactive phosphorus (DRP) fractions in unconcentrated lakewater is described. A reactive high molecular weight phosphorus (RHMW-P) fraction has been found in all waters studied and a second fraction, corresponding to orthophosphate (PO4-P) is frequently detected. The hydrolysis of RHMW-P to PO4-P by acid in the analytical reagents is shown to be the most likely reason for its determination as DRP. Key words: freshwater analysis, reactive phosphorus, orthophosphate, molybdenum blue method, gel filtration

scholarly journals Autosomal Factor VIII Deficiency in Rabbits: Size Variations of Rabbit Factor VIII.

1977 ◽  
Author(s):  
R.E. Benson ◽  
W.J. Dodds
Keyword(s):  
Molecular Weight ◽  
New Zealand ◽  
Factor Viii ◽  
High Molecular Weight ◽  
Gel Filtration ◽  
Low Molecular Weight ◽  
Antigenic Relationship ◽  
Genetic Studies ◽  
Coagulant Activity ◽  
Autosomal Inheritance

Many rabbits from our Flemish Giant-Chinchilla colony have moderate to severely reduced levels of factor VIII coagulant activity (FVIII-C). Some have shown prolonged bleeding after venipunctures and gastrointestinal and intramuscular hemorrhages. Genetic studies indicate autosomal inheritance. Gel filtration of plasma from these rabbits by the method of Rick et al. (Blood, 49, 209, 1977) at 25°C, pH 6.8 revealed two distinct peaks of FVIII-C; the majority of activity eluting as high molecular weight (HMW) material at the void volume (V°) followed by a much smaller low molecular weight (LMW) peak eluting close to that of fibrinogen. By contrast, filtration of plasma from New Zealand (NZ) rabbits produced threefold greater protein at the V° and equal amounts of HMW and LMW FVIII-C. Increasing the pH to 7.4 had little effect on FVIII-C recovery, although filtration at 4°C virtually abolished the HMW FVIII-C peak of NZ plasma. Rat antiserum (AS) to rabbit HMW FVIII-C, absorbed with precipitate low in FVIII-C, detected precipitating antigen in both HMW and LMW fractions. After absorption with rabbit fibrinogen, the AS no longer detected HMW V° material. The antigenic relationship between HMW and LMW FVIII-C and fibrinogen thus remains unclear. The differences in amount of HMW protein and the ratio of HMW to LMW FVIII-C suggest that in comparison to NZ rabbits our animals have a variant factor VIII molecule as well as low FVIII-C.

Glycodendrimers based on cellobiosyl-derived monomers

2002 ◽  
Vol 80 (8) ◽  
pp. 983-991 ◽  
Author(s):  
Stacey A Kalovidouris ◽  
W Bruce Turnbull ◽  
J Fraser Stoddart
Keyword(s):  
Molecular Weight ◽  
Key Words ◽  
High Molecular Weight ◽  
Reductive Amination

Reductive amination of suitably functionalized trisaccharide monomers, based on cellobiosylgalacto residues, has made it possible to construct high-molecular-weight glycodendrons and glycodendrimers for the display of large bioactive oligosaccharides and proteins in a well-defined manner. Key words: cellobiose, glycodendrimers, reductive amination, trisaccharide monomers.

Une étude du rôle des gluténines de haut poids moléculaire chez les blés hybrides: effet sur la qualité en situation d'hétérozygotie

1995 ◽  
Vol 75 (3) ◽  
pp. 633-642 ◽  
Author(s):  
F-X. Oury ◽  
M. Rousset ◽  
P. Bérard ◽  
P. Pluchard ◽  
G. Doussinault
Keyword(s):  
Molecular Weight ◽  
Winter Wheat ◽  
Key Words ◽  
High Molecular Weight ◽  
Wheat Bread ◽  
Hybrid Wheat ◽  
Grain Hardness ◽  
Bread Making ◽  
Wheat Hybrids ◽  
Chemical Hybridizing Agent

Thirty-three winter wheat hybrids produced using a chemical hybridizing agent and their 27 parents were compared for bread-making quality. The F1 was intermediate between the two parents for grain hardness, Pelshenke test and W of alveograph. Correspondence analyses and tree-based models showed strong associations between high molecular weight glutenin composition and Pelshenke or alveograph. For the Pelshenke test, the Glu-D1 encoded subunits were preponderant, and the effect of the alleles appeared additive between loci, as well as within locus. For the alveograph, Glu-B1 was the most important locus. Dominance effects appeared, involving the 7 + 8 allele associated with high values for tenacity and extensibility. Key words: Hybrid wheat, bread-making quality, high molecular weight glutenin, Pelshenke, alveograph, grain hardness

Plugging of the xylem vessel of barley induced by a high molecular weight phytotoxic glycoprotein from Rhynchosporium secalis

1989 ◽  
Vol 67 (7) ◽  
pp. 2077-2084 ◽  
Author(s):  
C. Mazars ◽  
P. Poletti ◽  
M. Petitprez ◽  
L. Albertini ◽  
P. Auriol
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Plant Response ◽  
Xylem Vessel ◽  
Rhynchosporium Secalis ◽  
Tissue Necrosis ◽  
Culture Filtrates ◽  
Barley Leaves ◽  
Leaf Tissues

Small concentrations of a high molecular weight phytotoxic glycoprotein obtained from culture filtrates of Rhynchosporium secalis (Oud.) Davis induced chlorosis and necrosis in barley; these symptoms were similar to those observed during the final stages of disease caused by this pathogen in naturally infected barley leaves. Histochemical studies indicated that cells of leaf tissues treated with the glycoprotein became disorganized. We observed changes such as the collapse of epidermal anticlinal walls, tissue necrosis, and plugging of xylem vessels. Histochemical and immunofluorescent techniques that localized the glycoprotein toxin indicated that, at least in part, the plugging results from a plant response stimulated by the toxic glycoprotein.

Microtubule motors and other maps

1990 ◽  
Vol 48 (3) ◽  
pp. 1-1
Author(s):  
Richard B. Vallee
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Cytoplasmic Dynein ◽  
Organelle Transport ◽  
Structural Components ◽  
Microtubule Associated Proteins ◽  
Microtubule Motors ◽  
Associated Proteins ◽  
The Subject ◽  
Intracellular Motility

Microtubules are involved in a number of forms of intracellular motility, including mitosis and bidirectional organelle transport. Purified microtubules from brain and other sources contain tubulin and a diversity of microtubule associated proteins (MAPs). Some of the high molecular weight MAPs - MAP 1A, 1B, 2A, and 2B - are long, fibrous molecules that serve as structural components of the cytamatrix. Three MAPs have recently been identified that show microtubule activated ATPase activity and produce force in association with microtubules. These proteins - kinesin, cytoplasmic dynein, and dynamin - are referred to as cytoplasmic motors. The latter two will be the subject of this talk.Cytoplasmic dynein was first identified as one of the high molecular weight brain MAPs, MAP 1C. It was determined to be structurally equivalent to ciliary and flagellar dynein, and to produce force toward the minus ends of microtubules, opposite to kinesin.

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