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Notes: A fourth streptococcal pyrogenic exotoxin (SPE D) was isolated from a pathogenic strain of group A streptococci cultured from a patient with a fatal case of streptococcal fasciitis associated with hypocalcemia and ‘toxic’ syndrome. SPE D was partially purified by differential solubility in ethanol and acetate-buffered saline and thin-layer isoelectric focusing. SPE D was antigenically distinct from the other streptococcal exotoxins SPE A, SPE B and SPE C. The isoelectric point of this exotoxin (4.6) was lower than those of the other SPEs. The Mr was estimated to be 13 000, and the biological activities were similar to the other exotoxins. SPE D reacted synergistically with SPE C (also present in this strain of streptococcus) to enhance the lethal effect of endotoxin in rabbits. The role of SPEs in the pathogenicity of this organism is discussed.

Notes: We have demonstrated the existence of a receptor that is specific for the Escherichia coli heat-stable enterotoxin (STa) on piglet's small intestine. The binding of STa to this receptor seemed specific, saturable and reversible. The receptor was demonstrated on brush border cells and membranes prepared from all of the piglets (n = 24) that developed clinical diarrhea when challenged with purified STa enterotoxin at the dose of 100 μg/kg body weight. The receptor was not demonstrated on intestinal brush border cells and membrane prepared from piglets (n = 3) that were refractory to the experimental induction of diarrhea. The data suggest that binding of the STa to a specific receptor on the small intestine of piglets is a prerequisite to the diarrheal response triggered by this toxin.

Notes: In checking harvesting discipline and quality control for oil palm fruits, color has presumably been an important guide to whether the oil content has reached a maximum where the fruit bunch is ready for cutting. However, establishing a single and harmonious standard base on color is a very contentious issue in the oil palm industry because of the subjective nature of the human vision of color. This was further complicated due to the lack of information on fruit color upon which to base a definite ripeness criterion. We demonstrated in this paper that this problem can be solved using machine vision technology. Methods used were to treat color in HSI (Hue, Saturation and Intensity) color space and applied multivariate discriminant analysis. These have proven to be highly effective for color evaluation and image processing. The vision system was trained to classify oil palms into four quality grades according to PORIM (Palm Oil Research Institute of Malaysia) inspection standards. These are the unripe, the underripe, the optimally ripe and the overripe classes. Depending upon the quality feature evaluated, misclassification by the vision system varied from 5 to 12% but averaged at about 8%. Machine vision disagreement ranged from 2 to 19%.

Notes: This article uses an integrative theoretical framework to review existing empirical research on the diversification-performance relationship along the three different research streams which have studied this relationship. the article highlights the considerable diversity in the findings across studies in each stream and identifies certain key theoretical and methodological issues which might help to explain the observed diversity. Also discussed is a contingency-based perspective and several useful directions for future research.

Notes: Abstract Seed development requires coordinated expression of embryo and endosperm and has contributions from both sporophytic and male and female gametophytic genes. Genetic and molecular analyses in recent years have started to illuminate how products of these multiple genes interact to initiate seed development. Imprinting or differential expression of paternal and maternal genes seems to be involved in controlling seed development, presumably by controlling gene expression in developing endosperm. Epigenetic processes such as chromatin remodeling and DNA methylation affect imprinting of key seed-specific genes; however, the identity of many of these genes remains unknown. The discovery of FIS genes has illuminated control of autonomous endosperm development, a component of apomixis, which is an important developmental and agronomic trait. FIS genes are targets of imprinting, and the genes they control in developing endosperm are also regulated by DNA methylation and chromatin remodeling genes. These results define some exciting future areas of research in seed development.

Notes: 1. The effects of the ACE inhibitor, captopril, on collagen metabolism in spontaneously hypertensive rats (SHR) with cardiac hypertrophy was examined. Captopril (100 mg/kg per day) was administered in drinking water to 20 week old male SHR for 12 weeks. Collagen concentration was calculated from hydroxyproline content, and relative proportions of types I, III and V collagen were determined by non-interrupted SDS-polyacrylamide gel electrophoresis (SDS-PAGE). These parameters were examined in age and sex matched Wistar-Kyoto (WKY) rats, as well as in non-treated SHR, and compared with those of captopril-treated SHR.2. Captopril significantly reduced both blood pressure (191 ± 12.1 vs 146 ± 11.2 mmHg, P 〈 0.01), and the ratio of left ventricular (LV) weight to bodyweight (BW; 2.38 ± 0.17 vs 2.05 ± 0.12 mg/g, P 〈 0.01). There were no significant differences in collagen concentration among WKY rats, captopril-treated SHR and non-treated 32 week old SHR. However, total collagen content in captopril-treated SHR reduced significantly compared with non-treated 32 week old SHR (16.8 ± 2.0 vs 21.3 ± 0.8 mg, P 〈 0.01). The relative proportion of type V collagen was significantly higher in both captopril-treated (58.6 ± 3.4 vs 46.8 ± 1.3%, P 〈 0.01) and non-treated 32 week old SHR (59.9 ± 3.1 vs 46.8 ± 1.3%, P 〈 0.01) compared with WKY rats. However, there were no significant differences between captopril-treated SHR and non-treated 32 week old SHR.3. The data from this study showed that captopril reduced cardiac hypertrophy, as reported previously, but did not change collagen types and concentration of the hypertrophied myocardium in SHR.

Notes: 〈list xml:id="l1" style="custom"〉1The effects of angiotensin converting enzyme (ACE) inhibition and beta-blockade on collagen in the heart and on plasma catecholamines and tissue angiotensin (Ang) I and II were examined in Bio 14.6 Syrian hamsters. Male hamsters (76–79 days old) were given low-dose enalapril (3 mg/kg per day), high-dose enalapril (30 mg/kg per day), atenolol (50 mg/kg per day) or vehicle for 65 days. Age and sex matched healthy F1b hamsters were used as controls. Collagen concentration was determined by measuring hydroxyproline content and the relative proportion of type I, III, and V collagens was obtained by non-interrupted sodium dodecyl polyacrylamide gel electro-phoresis (SDS-PAGE). Per cent collagen area (PCA) was measured by pixel counting in myocardial tissue by a personal computer.2Although heartweight (HW) and bodyweight (BW) in F1b controls were significantly higher compared with drugtreated groups and vehicles, the HW/BW ratio in cardiomyopathic Bio 14.6 hamsters tended to be high compared with F1b controls and was decreased by each drug treatment.3Collagen concentration, total collagen content and PCA in the heart of Bio 14.6 hamsters were significantly higher than F1b controls. Collagen concentration and total collagen content were significantly decreased in all drug-treated groups compared with vehicles.4The proportion of type I collagen tended to decrease while that of type III collagen tended to increase in all drugtreated groups compared with vehicles. Type V collagen in vehicle-treated group was significantly higher than in F1b controls, while it tended to decrease in all drug-treated groups compared with vehicles.5Plasma concentrations of catecholamines (adrenaline and noradrenaline) were decreased significantly by atenolol and high-dose enalapril, but not by low-dose enalapril. Tissue Angl remained unaltered in any of the drug-treated hamsters. Tissue Angll was decreased by the high-dose enalapril and beta-blockade, and tended to be decreased by low-dose enalapril treatment.6These results reveal that enalapril and atenolol produced similar beneficial effects on collagen remodelling in Bio 14.6 hamsters by decreasing the total amount of collagen, and also by changing collagen phenotypes through the inhibition of the renin-angiotensin system. Both drugs also improved myocardial morphological integrity.

Notes: This study replicates, refines, cross-validates and simplifies a scheme of operationalization and measurement of environmental dimensions proposed by Dess and Beard (1984). Employing a sample of 60 industries and data over a 16-year period, this study found considerable support for the viability of the three dimensions of munificence, dynamism and complexity. The data intensive and computationally complex operationalization scheme was simplified using a discriminant analysis approach and the discriminant functions were cross-validated using an alternate data set.