Physico-chemical investigations on varietal differences in rice

1937 ◽  
Vol 6 (1) ◽  
pp. 52-58
Author(s):  
K. Subbaramiah ◽  
Basrur Sanjiva Rao
Keyword(s):  
Varietal Differences ◽  
Physico Chemical

Water uptake in relation to pre-harvest sprouting damage in wheat: grain characteristics

1984 ◽  
Vol 35 (3) ◽  
pp. 337 ◽  
Author(s):  
RW King
Keyword(s):  
Water Uptake ◽  
Coat Colour ◽  
Grain Protein Content ◽  
Wheat Grain ◽  
Wheat Varieties ◽  
Varietal Differences ◽  
Water Imbibition ◽  
Grain Dormancy ◽  
Physico Chemical ◽  
Other Information

Water uptake by mature (post-dormancy) wheat grain was studied for a group of 50 wheat varieties of mostly Australian origin and in lines near-isogenic for grain coat colour (red v. white) and for hard v. soft grain. Cultivars differed widely (up to two-fold) in grain water uptake. Apparently these differences related to physico-chemical aspects of water imbibition by the grain. However, neither grain coat colour, pericarp or testa thickness, grain hardness nor grain protein content was correlated with grain water uptake. The degree of seed coat cracking was minimal as grain was dissected by hand from the ears. Grain germination after 30 h exposure to moisture was significantly correlated with its water uptake after 2 h of imbibition (r = 0.61). These findings, when combined with other information from this laboratory on varietal differences in ear water uptake, usefully characterize in-ear sprouting. Of the varietal differences in sprouting, 18% can be accounted for by differences in ear and grain water uptake. Differences in grain dormancy were deliberately avoided in these studies, but were evaluated separately at harvest ripeness in this same experiment. On the basis of varietal differences in grain dormancy and water uptake some breeding options are highlighted.

Decoration of specific sites on freeze-fractured membranes

1978 ◽  
Vol 36 (2) ◽  
pp. 140-141
Author(s):  
H. Gross ◽  
H. Moor
Keyword(s):  
Pure Water ◽  
Freeze Fracture ◽  
Chemical Properties ◽  
Surface Forces ◽  
Sulfate Pentahydrate ◽  
Copper Sulfate Pentahydrate ◽  
Physico Chemical ◽  
Water Of Hydration ◽  
Small Container ◽  
Binding Forces

Fracturing under ultrahigh vacuum (UHV, p ≤ 10-9 Torr) produces membrane fracture faces devoid of contamination. Such clean surfaces are a prerequisite foe studies of interactions between condensing molecules is possible and surface forces are unequally distributed, the condensate will accumulate at places with high binding forces; crystallites will arise which may be useful a probes for surface sites with specific physico-chemical properties. Specific “decoration” with crystallites can be achieved nby exposing membrane fracture faces to water vopour. A device was developed which enables the production of pure water vapour and the controlled variation of its partial pressure in an UHV freeze-fracture apparatus (Fig.1a). Under vaccum (≤ 10-3 Torr), small container filled with copper-sulfate-pentahydrate is heated with a heating coil, with the temperature controlled by means of a thermocouple. The water of hydration thereby released enters a storage vessel.

Activation of cytochrome c to a peroxidase compound I-type intermediate by H2O2: relevance to redox signalling in apoptosis

2004 ◽  
Vol 71 ◽  
pp. 97-106 ◽  
Author(s):  
Mark Burkitt ◽  
Clare Jones ◽  
Andrew Lawrence ◽  
Peter Wardman
Keyword(s):  
Cytochrome C ◽  
Hydroxyl Radical ◽  
Redox Regulation ◽  
Chemotherapeutic Agents ◽  
Tyrosyl Radical ◽  
Compound I ◽  
Definitive Evidence ◽  
Enhanced Production ◽  
Physico Chemical

The release of cytochrome c from mitochondria during apoptosis results in the enhanced production of superoxide radicals, which are converted to H2O2 by Mn-superoxide dismutase. We have been concerned with the role of cytochrome c/H2O2 in the induction of oxidative stress during apoptosis. Our initial studies showed that cytochrome c is a potent catalyst of 2′,7′-dichlorofluorescin oxidation, thereby explaining the increased rate of production of the fluorophore 2′,7′-dichlorofluorescein in apoptotic cells. Although it has been speculated that the oxidizing species may be a ferryl-haem intermediate, no definitive evidence for the formation of such a species has been reported. Alternatively, it is possible that the hydroxyl radical may be generated, as seen in the reaction of certain iron chelates with H2O2. By examining the effects of radical scavengers on 2′,7′-dichlorofluorescin oxidation by cytochrome c/H2O2, together with complementary EPR studies, we have demonstrated that the hydroxyl radical is not generated. Our findings point, instead, to the formation of a peroxidase compound I species, with one oxidizing equivalent present as an oxo-ferryl haem intermediate and the other as the tyrosyl radical identified by Barr and colleagues [Barr, Gunther, Deterding, Tomer and Mason (1996) J. Biol. Chem. 271, 15498-15503]. Studies with spin traps indicated that the oxo-ferryl haem is the active oxidant. These findings provide a physico-chemical basis for the redox changes that occur during apoptosis. Excessive changes (possibly catalysed by cytochrome c) may have implications for the redox regulation of cell death, including the sensitivity of tumour cells to chemotherapeutic agents.

Freeze-Dried Matrices for Buccal Administration of Propranolol in Children: Physico-Chemical and Functional Characterization

2020 ◽  
Author(s):  
Angela Abruzzo ◽  
Alessandra Crispini ◽  
Cecilia Prata ◽  
Rosanna Adduci ◽  
Fiore Pasquale Nicoletta ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Physico Chemical ◽  
Freeze Dried
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