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Notes: Abstract In this paper we present a quantitative comparison between a large data base of medium-scale atmospheric gravity waves (AGWs) observed by radio interferometry of transionospheric radio sources and the results of a numerical simulation of the observed effects. The simulation includes: (i) the propagation and dissipation of AGWs up to ionospheric heights and (ii) the calculation of the subsequent slant TEC perturbations integrated along the path to the radio sources. We show that the observed azimuthal distribution of AGWs can be deeply biased. Predicted results are found to be consistent with previous extensive observations using radio beacons aboard geostationary satellites. These observations are rediscussed in view of the present predictions.

Notes: The fine structure of laboratory purified broadbean and smooth pea starches, with an amylose content of 32-34%, has been studied by pullulanase debranching, before or after beta-amylolysis, and by the properties of the chemically fractionated amylose and amylopectin. The enzymatic study has shown the presence of the three chain populations (DP 〉 60, 45 and 15) observed with other starches. The linear DP 15 and 45 chains occur in a ratio of 8.5 for broadbean and 9.75 for pea, which indicates an amylopectin similar to cereal starches. The λmax, beta-amylolysis limit and intrinsic viscosity of the two amylopectins confirm the cereal-like nature. The two amylose components are not completely linear according to their beta-amylolysis limit of 81.5% which corroborates the in complete debranching of the total starch. The physical structure, studied by X-ray diffractometry, is of C-type. By submitting legume starch granules to mild acid hydrolysis (lintnerization), a residue has been obtained from both starches, which has an increase in the crystalline fraction, with a tendency towards the A-type pattern for broadbean and the B-type for pea. The crystallites are mainly formed of linear chains (CL 15) with some singly branched material (DP 25). Gelatinization of starch granules occurs at 44-65-86°C for broadbean with a heat of gelatinization of 3.8 cal g−1 and at 48-61-80°C for pea with a heat of gelatinization of 3.2 cal g−1.

Notes: A purified endopolygalacuronase (endo PG) from Aspergillus niger has been characterized. The optimum temperature was 45°C and the optimum pH was 4.1–4.2 with a highest stability at pH 6. The purified enzyme was a typical endo PG: the enzyme hydrolyzes about 56.7% and 7% of the glycosidic linkages of polygalacturonic acid and pectin (DE = 72.8%), respectively, and a loss of 50% in viscosity of polygalacturnoic acid was reached when only 2.3% of the glycosidic linkages of the substrate were split. The products at the maximum hydrolysis were mono-, di- and trigalacturonic acids. Endo PG has a Vmax of 239 μ mole reducing groups per min per mg of protein and a Km of 0.44 mg per ml of polygalacutronic acid (DPn= 44). Sodium, potassium and ammonium ions stimulated endo PG activity, while divalent ions, or ethylene — diamine – tetracetic acid had no effect.Pectinolytic enzymes (saponifying enzymes and depolymerases) are widespread in nature; they are produced by bacteria, fungi and higher plants (Rombouts and Pilnik 1972; MacMillan and Sheiman 1974). They are involved in natural processes, as fruit physiological changes (Pilnik and Voragen 1970) and they are responsible for the phytopathogenicity of many microorganisms (Rexova-Benkova and Markovic 1976).These enzymes are very useful for their applications in food processing. Commercial preparations of fungal pectinolytic enzymes are employed in the production of fruit and vegetable juices (Rombouts and Pilnik 1978). These preparations contain mainly pectinesterases (pectin-pectyl hydrolase, E.C. 3. 1. 1. 11 and endopolygalacturonase (poly (1, 4 α D galacturonide) glycanohydrolase, E.C. 3. 2. 1. 15); for this reason, special attention was paid to endopolygalacturonase (endo PG (ENDO, 1964a, 1964b, 1964c; Yamasaki et al. 1966). Purified endo PG was also used as a tool for specific degradations of pectic substances (Talmadge et al. 1973) or material containing galacturonic acids (Kikuchi and Yokotsuka, 1973; Kikuchi and Sugimoto, 1976).In a previous paper (Thibault and Mercier 1978) we have described a rapid method for the purification of endo PG from a commercial preparation of pectolytic enzymes. This method is based on a remark of English et al. (1972) who observed that endo PG was delayed during chromatography on agarose gel (Bio-Gel A 0.15 m). We demonstrated that dialyzed endo PG from a crude preparation can be optimally bound by ion-exchange (Thibault 1978) to the agarose gel (Sepharose 6B) when the column is eluted at pH 4.3–4.4 (20 mM acetate buffer). The endo PG released by a 0–0.15 M NaCl gradient is therefore purified 62 times if the activity is determined by a viscosimetric method and 36 times if the activity is expressed in n. katals (cf. enzyme assay methods for the definitions). The present paper reports characterization and some physico-chemical properties of the purified enzyme.