Genotypic variation for cold tolerance during reproductive development in rice: Screening with cold air and cold water

Rice (Oryza sativa L.) plants are susceptible to low temperature during the young microspore stage, which occurs 10-12 days before heading. Low temperature at this time increases spikelet sterility which can cause massive yield loss. Increasing the cold tolerance of cultivars can reduce yield variability in temperate rice-growing environments. Two experiments were conducted in cold air screenings and two were conducted in cold water screenings to examine genotypic variation for cold tolerance, explore flowering traits related to spikelet sterility, and investigate whether the results reflect the level of cold tolerance determined previously in the field. Cold air screenings imposed day/night temperatures of 27 degrees C/13 degrees C, 25 degrees C/15 degrees C and 32 degrees C/25 degrees C following particle initiation until 50% heading, while cold water screenings maintained a relatively constant 19 degrees C. The variation in the commencement of low air temperature treatment did not have an effect on the level of spikelet sterility, indicating that exposure to low temperature during the young microspore stage was more important than the duration of exposure. Spikelet sterility of common cultivars showed a significant correlation between cold air and cold water screenings (r(2) = 0.63, p < 0.01), cold air and field screenings (r(2) = 0.52, p < 0.01) and cold water and field screenings (r(2) = 0.53, p < 0.01), indicating that cold air and cold water can be used for screening genotypes for low temperature tolerance. HSC55, M 103 and Jyoudeki were identified as cold tolerant and Doongara, Sasanishiki and Nipponbare as susceptible cultivars. There was a significant negative relationship between spikelet sterility and both the number of engorged pollen grains per anther and anther area only after imposing cold air and cold water treatment hence, it was concluded that these flowering traits were facultative in nature. In addition, cultivars originating from Australia and California were inefficient at producing filled grain with similar sized anthers containing a similar number of engorged pollen grains as cultivars from other origins. One suggested reason for this poor conversion to filled grain of cultivars from Australia and California may be associated with their small stigma area, particularly when exposed to low temperature conditions. (c) 2006 Elsevier B.V. All rights reserved.

NMR of conotoxins: structural features and an analysis of chemical shifts of post-translationally modified amino acids

Conotoxins are small conformationally constrained peptides found in the venom of marine snails of the genus Conus. They are usually cysteine rich and frequently contain a high degree of post-translational modifications such as C-terminal amidation, hydroxylation, carboxylation, bromination, epimerisation and glycosylation. Here we review the role of NMR in determining the three-dimensional structures of conotoxins and also provide a compilation and analysis of H-1 and C-13 chemical shifts of post-translationally modified amino acids and compare them with data from common amino acids. This analysis provides a reference source for chemical shifts of post-translationally modified amino acids. Copyright (C) 2006 John Wiley & Sons, Ltd.

Relationship between bicarbonate retention and bone characteristics in broiler chickens

Determination of the bicarbonate retention factor (BRF) is an important step during development of the indicator amino acid oxidation technique for use in a new model. A series of 4-h oxidation experiments were performed to determine the BRF of broilers aged 7, 14, 21, 28, 35, and 42 d using 4 birds per age group. A priming dose of 1.2 mu Ci of (NaHCO3)-C-14, followed by eight half-hourly doses of 1 mu Ci of (NaHCO3)-C-14 were given orally to each of 4 birds per age. The percentage of 14 C dose expired by the bird at a steady state was measured. These birds, as well as 12 additional birds matched for age and BW, were killed, and femur bone mineral density was measured by quantitative computed tomography to determine the relationship between bone development and bicarbonate retention at each age. There was a correlation (r = 0.50; P < 0.05) between total cross-sectional femur bone mineral density and bicarbonate retention at each age. A prediction equation (Y = 6.95 x 10(-2) X - 3.51 x 10(5)X(2) + 27.58; P < 0.0001, R-2 = 0.79) where Y = bicarbonate retention and X = BW was generated to predict Y as a function of X. Bicarbonate retention values peaked at 28 d, during the stage of the most rapid bone deposition and the highest growth rate. A constant BRF was found from 1,900 to 2,700 g of BW of 35.15 +/- 1.095% (mean SEM). This retention factor will allow the accurate correction of oxidation of C-14-labeled substrates in broilers of different ages and BW in future indicator amino acid oxidation studies.

SCOTROC 2A: Carboplatin followed by docetaxel or docetaxel gemcitabine as first-line chemotherapy for ovarian cancer

The feasibility of sequential carboplatin followed by docetaxel-based therapy for untreated ovarian cancer was determined. Patients received four q3w cycles of carboplatin AUC 7, then four q3w cycles of either docetaxel 100 mg m(-2) (day 1) (arm A); docetaxel 75 mg m(-2) (day 8) and gemcitabine 1250 mg m(-2) (days 1,8) (arm B) or docetaxel 25 mg m(-2) and gemcitabine 800 mg m(-2) (both given weekly (days 1,8,15)) (arm C). A total of 44 patients were randomised to each treatment arm. None of the arms demonstrated an eight cycle completion rate (70.5/72.7/45.5% in arms A/B/C, respectively), which was statistically greater than 60% (P = 0.102, P = 0.056, P = 0.982) which was our formal feasibility criteria, although only the completion rate in arm C was clearly worse than this level. The overall response rate (ORR) after carboplatin was 65.7% in 70 evaluable patients. In evaluable patients, ORRs after docetaxel-based cycles were: arm A 84.0% (21 out of 25); arm B 77.3% (17 out of 22); arm C 69.6% (16 out of 23). At follow-up (median 30 months), median progression-free survival times were: arm A 15.5 months (95% Cl: 10.5 - 20.6); arm B 18.1 months (95% Cl: 15.9 - 20.3); arm C, 13.7 months (95% Cl: 12.8 - 14.6). Neutropenia was the predominant grade 3 - 4 haematological toxicity: 77.8/85.7/54.4% in arms A/B/C, respectively. Dyspnoea was markedly increased in both gemcitabine-containing arms (P = 0.001) but was worse in arm C. Although just failing to rule out eight cycle completion rates less than 60%, within the statistical limitations of these small cohorts, the overall results for arms A and B are encouraging. Larger phase III studies are required to test these combinations.

Three classes of starch granule swelling: Influence of surface proteins and lipids

The role of non-carbohydrate surface components of granular starch in determining gelatinisation behaviour has been tested by treatment of native starches with a range of extractants. Resulting washed starches were analysed for (bio)chemical, calorimetric and theological properties. Sodium dodecyl sulphate (SDS) was the most efficient extractant tested, and resulted in major changes to the subsequent theological properties of wheat and maize starches but not other starches. Three classes of starch granule swelling behaviour are identified: (i) rapid swelling (e.g. waxy maize, potato), (ii) slow swelling that can be converted to rapid swelling by extraction of surface proteins and lipids (e.g. wheat, maize), and (iii) limited swelling not affected by protein/lipid extraction (e.g. high amylose maize/potato). Comparison of a range of extractants suggests that all of protein, lipid and amylose are involved in restriction of swelling for wheat or maize starches. Treatment of starches with SDS leads to a residue at comparable (low) levels of SDS for all starches. C-13 NMR analysis shows that this SDS is present as a glucan inclusion complex, even for waxy maize starch. We infer that under the conditions used, glucan inclusion complexation of SDS is equally likely with amylopectin as with amylose. (c) 2006 Elsevier Ltd. All rights reserved.