Frequency of x-ray induced mitotic recombination in genotypes with different X-Y-combination-chromosomes in Drosophila melanogaster

Summary In first and second instar larvae of Drosophila melanogaster mitotic recombination has been induced by X-rays. Resulting mosaic spots were analysed in the eyes of adult females. The five examined genotypes varied in the combination of different X-chromosomes and in the presence or absence of the duplication Dp(1;3)N ^264-58. X-chromosomes used have been elongated by proximally or distally linked arms of the Y-chromosome. The portion of Y-heterochromatin in the genome is negatively correlated with the frequency of twin mosaic spots (Fig. 1). The frequency of these spots is lower in flies bearing the duplication than in those without the duplication. With respect to the X-chromosome combinations, there are no marked differences in the frequencies of single mosaic spots (Fig. 2); with respect to the duplication they are absent. In the genotype Y ^S X/X.Y ^S prophases of neuroblast mitoses (Fig. 4) show normal pairing of homologous chromosome sections. Reasons for the different spot frequencies are discussed.

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Vorgelegt von E. Hadorn     

Transdetermination in leg imaginal discs ofDrosophila melanogaster undDrosophila nigromelanica

Summary The transdetermination capacities of leg discs ofDrosophila melanogaster were examined by mechanically disrupting and kneading whole discs from late third instar larvae and by culturing the resulting tissue mass for 10–14 days in adult female abdomens where the cells continued to divide. The grown implants were then dissected from the abdomens and injected into third instar larvae to undergo metamorphosis.After this treatment, prothoracic leg discs ofDrosophila melanogaster transdetermined with a high frequency (59% of all implants) to wing. Mesothoracic leg discs also transdetermined to wing, but at a very low frequency (4%). Metathoracic leg discs exhibited the same low frequency of transdetermination (4%), but in this case the direction of transdetermination was to haltere (Table 1,D. melanogaster).Very similar results were obtained with leg discs ofDrosophila nigromelanica (Table 1,D. nigromelanica), showing that the peculiar behavior of the three leg discs is not unique forDrosophila melanogaster.The homeotic mutation Polycomb (Pc ³) which partially transforms meso- and metathoracic legs into prothoracic legs did not significantly increase the frequencies of transdetermination in these leg dises and had clearly no effect on the direction of transdetermination (Table 1).We dedicate this publication to the memory of our teacher and advisor, the late Professor Ernst Hadorn, whose enthusiasm and interest stimulated our work     

Homoeotische flügelbildung durch dasloboid-allel “ophthalmoptera” (ld oph ) beiDrosophila melanogaster

In awhite-apricot (w^a) stock, a new mutant was found which reduces the eyes and produces wing-structures in the eyes. This homeotic effect can occur with a high frequency, depending on temperature and genetic background. The mutant is an allele ofloboid (ld, 3–102±) and ofeyesreduced (eyr, 3–103±); the designationloboid-ophthalmoptera (ld^oph) is proposed. The varying contours of the reduced eye inld ^oph fit into a pattern which is quite similar to the cell-lineage pattern established byBecker (1957) for the normal eye. This indicates that inld ^oph-eyes one or more cell-lineage sectors are missing because the corresponding cell families are not competent to differentiate into ommatidia. Genal and orbital bristle rows are frequently doubled, and isolated clusters of bristles occur on the gena. In sectors devoid of ommatidia, “allotypic” wing structures are differentiated. These consist of wing membrance and fragments of anterior and posterior wing border in haphazard combination, and together form a balloon filled with hemolymph. The striking similarity between the homeotic mutation and transdetermination of cultured imaginaldisks (Hadorn, 1966) is discussed.      

Evidence of a responsible gene for the thermosensibility during laying-season with Drosophila melanogaster

Summary A recessive gene that makes oogenesis and development heat sensitive has been found in a laboratory strain of Drosophila melanogaster homozygous for sepia. The new mutation called pts (ponte thermosensible) is located on chromosome III, near the locus of sepia. When eggs are collected from females kept at 30°C, two observations can be made:The rate of egg laying is reduced, oogenesis being stopped reversibly at stage 7 of ovarian cystes.Eggs which have gone through this stage before the temperature was raised are deposited, but fail to hatch, even when their own genotype is heterozygous pts/pts ⁺.Heat shocks applied at later periods to pts/pts homozygous show the existence of two others periods of temperature sensitivity located respectively at the beginning of embryogenesis and of larval stage.

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Directeur: Ph. L'Héritier

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Mémoire présenté par E. Hadorn     

Analysis of the stability of yellow position-effect variegation in cultures of imaginal discs of Drosophila melanogaster

Summary Primordia from imaginal discs of a yellow-variegated strain of Drosophila melanogaster were cultivated in the abdomens of adult females. Test fragments were transplanted back into larvae. After metamorphosis the yellow variegation and the type of differentiation were studied in the imaginal structures of the implants. Distribution and extent of the variegation were first investigated in situ.After repeated fragmentation and establishing a series of subcultures, we tried to obtain pure wild-type lines and pure yellow lines. Stable wild-type clones were obtained frequently, in which variegation no longer occurred in lines cultivated over 25 transfer generations. This corresponds to more than 100 cell generations. On the other hand we failed in stabilazing pure yellow clones, probably because of a reduced proliferation of the yellow cells. Cultures of genital, wing and antenna imaginal discs gave the same results with respect to the position-effect variegation (Figs. 2–6).It was shown that transdetermination does not affect the pattern of variegation. Autotypic mosaic blastemas lead to allotypic mosaics of yellow and wild-type bristles. Thus transdetermination occurs in several cells simultanously. From wild-type transdetermining clones, cultivated over many transfer generations, arise only wild-type structures; conditions for a new clonal initiation are not restored. The results support the hypothesis that transdetermination leads directly from one determined state to another. Arguments are presented for separate controls of organ determination and the variegation process.

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Meinem verehrten Lehrer, Herrn Prof. Dr. E. Hadorn, möchte ich für die Überlassung des Themas und für seine Leitung und Förderung dieser Arbeit herzlich danken, ebenso Herrn Prof. Dr. J. Schultz (Baltimore) für wegweisende Beratung. Herrn Dr. G. Schubiger danke ich für die Einführung in die Technik und Herrn Dr. W. Janning für die kritische Durchsicht des Manuskripts.     

Autonome Determination für Pigmentbildung beimwhite-Positionseffekt vonDrosophila melanogaster

Zusammenfassung Beimwhite-Positionseffekt vonDrosophila melanogaster findet die Determination für Pigmentbildungspotenzen der Augenzellen am Ende des ersten Larvenstadiums statt. Augenimaginalscheiben wurden vor oder nach diesem Zeitpunkt zusammen mit möglichst wenig larvalem Gewebe aus Larven entnommen und in die Abdomina adulter Weibchen transplantiert. Nach einer Kultivierungsdauer von 5–7 Tagen wurden die Implantate in Larven rücktransplantiert, mit denen sie die Metamorphose durchliefen. Es konnte gezeigt werden, daß die Augenanlagezellen auch während der Kultivierungsperiode im Adultabdomen autonom determiniert werden. Ein Einfluß mittransplantierten Larvalgewebes auf die Determination konnte nicht nachgewiesen werden. Dieser Determinationsvorgang ist daher sehr wahrscheinlich unabhängig vom spezifischen Larvalmilieu.

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Autonomous determination for pigment formation inwhite position-effect ofDrosophila melanogaster

Summary Inwhite position-effect ofDrosophila melanogaster, determination for the potential of pigment formation of eye cells takes place at the end of the first larval instar. Eye discs, prior to or after this developmental stage, were transplanted together with some larval tissue into the abdomens of adult females. After a cultivation period of 5 to 7 days, the implants were transplanted back into larvae. Imaginal differentiation occurred in these metamorphosing hosts. It could be shown that eye disc cells become autonomously determined during the cultivation period. An influence of the larval tissues transplanted together with the eye discs on determination could not be demonstrated. Therefore, this determinative event most likely is independent on the specific larval milieu.

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Die Arbeit wurde durch ein Stipendium der Deutschen Forschungsgemeinschaft gefördert. Prof. Dr. E. Hadorn danke ich sehr für die Möglichkeit, die Untersuchung in Zürich durchzuführen; ihm sowie Dr. G. Mindek bin ich dankbar für anregende Diskussion, Dr. A. Dübendorfer für die Einführung in die Technik.     

Bestimmung des Heterochromatisierungsstadiums beim white-Positionseffekt mittels r?ntgeninduzierter mitotischer Rekombination in der Augenanlage von Drosophila melanogaster

Summary Position-effect variegation of eye pigmentation in the examined Dp(1;3)N ^264-58 females is due to an insertion of a X-chromosome section including the white-locus into the proximal heterochromatic region of the third chromosome. The light and dark pigmented areas have a cell lineage basis (Fig. 2). Flies bearing the w ⁺-duplication had two X-chromosomes marked with w ^a lz ⁵⁰ e and w ^a rb rux ² respectively (Fig. 3). X-ray induced mitotic recombination in presumptive eye cells of larvae resulted in w ^a lz ^50e /w ^a rb rux ² twin mosaic spots in the adult eyes. After young larvae were treated twin spots appeared, which had one partner light colored and one dark. Such combinations were rarely found after older larvae were treated. Treatment of young larvae in addition produced twin spots with one or both partners variegated (Figs. 5 and 6). Sometime after the stage at which younger larvae were treated and before the stage at which older larvae were treated the translocated w ⁺-gene in each cell was determined for function or no function. As a result the progeny of each of these cells synthesized pigment or not during the pupal stage. At a temperature of 25.5° C the developmental phase during which determination, i.e. heterochromatization of the white gene, takes place, begins not earlier than 39 hours after egg laying and ends about 8 hours later (Fig. 7). In females heterozygous for the short arm of the heterochromatic Y-chromosome linked distally to the X-chromosome (Y ^S X/X) one twin spot partners is homozygous for this arm (Y ^SX/Y^S X), the other lacks it (X/X; Fig.4a). The Y ^SX/Y^S X-partner were more frequently dark pigmented than the X/X-partners (Tables 3 and 4). This shows that heterochromatization of the translocated w ⁺-genes is markedly influenced by the genotype of the single cell. When two genotypes with varied amounts of heterochromatin were compared (Fig. 4) no difference in the phases of heterochromatization could be observed (Table 5). Therefore, when position-effect variegation is modified by varying the amount of heterochromatin in the genome the modification is probably not due to a shift in the phase of heterochromatization.

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Vorgelegt von E. Hadorn     

Besprechungen

Book reviewed in this article: Walker , Use (1972): Habituation to disturbance in the Fiddler Crab (Uca annulipes) in its natural environment (Freilandbeobachtungen über die Gewöhnung an Störungen bei der Winkerkrabbe U. a.). Matthes , Dieter (1972): Vom Liebesleben der Insekten. Kleine Sittengeschichte der Sechsbeiner. Curry-Lindahl , Kai (1961): Fiskarna i Färg. 4. Aufl. Almqvist und Wiksel Stockholm. Peeke , Harman V. S., und Shirley C. Peeke (1972): Habituation, reinstatement and recovery of predatory responses in two species of Teleosts, Carassius auratus and Macropodus opercularis (Abgewöhnen, Wiedererwecken und Erholung im Beuteverhalten des Gold- und des Paradiesfisches). Pickwell , Gayle (1972): Amphibians and reptiles of the Pacific States. Taylor , Douglas H. (1972): Extra-optic photoreception and compass orientation in larval and adult salamanders (Ambystoma tigrinum) (Sonnenkompaß-orientierung mit den Stirnaugen beim Tigerquerzahnmolch [A. t.]). Wiens , John A. (1972): Anuran habitat selection: early experience and substrate selection in Rana cascadae tadpoles (Beeinflußt frühe Erfahrung die Wohnraumwahl von Fröschen?). Phillips , R. E. (1972): Sexual and agonistic behaviour in the Killdeer (Charadrius vociferus) (Paarungs- und Kampfverhalten des Killdeer-Regenpfeifers). Peek , Frank W. (1972): An experimental study of the territorial function of vocal and visual display in the male Red-winged Blackbird (Agelaius phoeniceus) (Versuche zur Frage der Wirksamkeit reviermarkierender stimmlicher und visueller Signalreize bei Rotschulterstärlings-♂♂). Potash , Lawrence M. (1972): A signal detection problem and possible solution in Japanese Quail (Coturnix coturnix japonica) (Die Frage nach der Ortbarkeit von Rufen japanischer Wachtel-♂♂ und ihre mögliche Lösung). Thorpe , W. H., unter Mitarbeit von J. Hall-Craggs, B. und T. Hooker und R. Hutchison (1972): Duetting and antiphonal song in Birds, its extent and significance (Zweistimmiger und Wechselgesang bei Vögeln, sein Ausmaß und seine Bedeutung). Schmidt-Koenig, K. , und H. J. Schlichte (1972): Homing in Pigeons with impaired vision (Heimkehrleistungen von kaum mehr bildsehenden Tauben). Short , L. L. (1971): Systematics and behavior of some North American Woodpeckers, Genus Picoides (Aves) (Systematik und Verhalten einiger nordamerikanischer Picoides-Spechte). Fossey , Dian (1972): Vocalizations of the Mountain Gorilla (Gorilla gorilla beringei) (Der Lautschatz des Berggorillas). Jantschke , F. (1972): Orang-Utans in Zoologischen Gärten. Ethologische Studien. Herausgeber W. Wickler, mit einem Vorwort von Bernhard Grzimek. Lawick-Goodall , Hugo und Jane van (1972): Unschuldige Mörder. Bei den Raubrudeln in der Serengeti. Übersetzt von Margaret Carroux. Lott , Dale F., and John H. Hopwood (1972): Olfactory pregnancy-block in Mice (Mus mnsculus), an unusual response acquisition paradigm (Schwangerschaftsunterbrechung bei Mäusen durch Duftreize, Beispiel für einen ungewöhnlichen Erwerb eines Antwortverhaltens). Carter , Carol Sue (1972): Effects of olfactory experience on the behaviour of the Guinea-pig (Cavia porcellus) (Der Einfluß bekannter Gerüche auf das Verhalten von Meerschweinchen). Sales , Gillian D., geb. Sewell (1972): Ultrasound and aggressive behaviour in rats and other small mammals (Ultraschall und Angriffsverhalten bei Ratten und anderen Kleinsäugern). Herbert , Harry John (1972): The Population Dynamics of the Waterbuck, Kobus ellipsiprymnus (Ogilby, 1833) in the Sabi-Sand Wildtuin (Populationsdynamik des Wasserbocks in der Sabi-Sand Wildtuin). ?Mammalia depicta”, Beiheft 7 zur Zeitschrift für Säugetierkunde. Nievergelt , Bernhard (1966): Der Alpensteinbock (Capra ibex L.) in seinem Lebensraum, ein ökologischer Vergleich. Mammalia depicta. Haider, U. , und R. Schenkel (1972): Das Riechgähnen bei Rindern (Bovinae). Z. Säugetierkde. Curry-Lindahl , Kai (1967): Djuren i Färg. 5. Auflage. Almqvist und Wiksel. Stockholm. 200 S., Farbbilder von 109 Säugetieren Kaplan , Reinhard W. (1972): Der Ursprung des Lebens. Biogenetik, ein Forschungsgebiet heutiger Naturwissenschaft. ed. Grassé , P. P. (1971): Allgemeine Biologie Band 2: P. Laviolette und P. P. Grassé : Fortpflanzung und Sexualität. Armin Heymer und Leni Heymer-Reich übersetzten: Biologie Generale II. Reproduction et Sexualité (1966). Kühn , Alfred, Ernst Hadorn und Rüdiger Wehner (1972): Allgemeine Zoologie. DTV Wissenschaftliche Reihe. ed. Grasse, G. (1972): Alfred Kühn zum Gedächtnis. 5. Biologisches Jahresheft des Verbandes Deutscher Biologen. Eulefeld , Günter (1972): Biologie in Stichworten, III: Zoologie (Cytologie–Histologie–Systematik).     

Functional morphology of the hindleg in two kangaroos Macropus giganteus and Aepyprymnus rufescens

In this study the structures in the hindleg of the kangaroo which are potentially available for jumping were examined. Specimens of two species, Macropus giganteus and Aepyprymnus rufescens, were examined and are described and compared. The basic pattern of the jump of the two species is similar. This is reflected anatomically by the fact that in both species the extensors of the hip, knee and ankle as a percentage of the total weight of the hindleg are greater than the flexors of the same joints. An additional similarity is that the biceps femoris and adductor magnus have the greatest share in the weight of the hip extensors. Furthermore the estimated total force of the hip, knee and ankle extensors and total moment of the hip and ankle extensors are always greater than the flexors of the same joints. However, the percentage of the hip and knee extensors, the absolute forces and moments of both the extensors and flexors and the range of movement especially of the hip and knee are always greater in M. giganteus than in A. rufescens. As well as these differences, the long tibia and the position of the knee in view of the hip may be important factors for the longer jump achieved by M. giganteus. In comparison A. rufescens has a anatomical construction which seems to be a compromise between walking and jumping.     

马铃薯'转心乌'块茎色素的组成和含量

马铃薯转心乌块茎的内、外韧皮部和髓为淡黄色,周皮和木质部为紫色;木质部的紫色形成一个不规则的环",并向内韧皮部蔓延.系列特征颜色反应和紫外可见光谱分析表明:‘转心乌’块茎紫色素属于黄酮类化合物,可能含有酚性邻位二羟基,并被肉桂酸酰化,不含类胡萝卜素、查耳酮、噢哢、异黄酮、儿茶素;花色苷和/或其苷元花色素奠定了‘转心乌’块茎着色的基础,其它的非红色的黄酮类化合物发挥共色素的作用.块茎的皮"紫色最浓","环"其次,"肉"最淡,这与"皮"、"环"和"肉"的色价、花色苷含量和总黄酮类化合物含量的变化趋势呈正相关.     

黄土高原小叶杨与其他树种枯落叶混合分解对土壤性质的影响

将小叶杨分别与其他11个树种枯落叶粉碎混合后进行室内分解培养,分析不同树种枯落叶混合分解对土壤性质的影响及其相互作用.结果表明:12个树种枯落叶单独混土分解均明显提高了土壤脲酶、脱氢酶、磷酸酶活性和有机质、碱解N含量,但对土壤速效P含量和土壤阳离子交换量(CEC)的影响差异较大,其中柠条和紫穗槐枯落叶改善土壤性质的效果明显.小叶杨分别与油松、侧柏、刺槐、白榆枯落叶混合分解,对土壤微生物数量的影响存在相互促进作用;小叶杨分别与侧柏、柠条枯落叶混合分解对土壤有机质、速效P、速效K含量和CEC的影响存在相互促进作用,但对土壤大部分酶活性的影响却存在相互抑制作用;小叶杨与落叶松枯落叶混合分解对土壤多数酶活性和养分含量的影响存在相互促进作用,而与樟子松枯落叶混合分解时则有抑制作用.总体上,小叶杨分别与白榆、油松、落叶松和刺槐枯落叶混合分解可促进土壤性质的改善,而与侧柏、柠条、樟子松、沙棘和紫穗槐枯落叶混合分解时则相互抑制.     

Biomimetic nanosystems and novel composite nanobiomaterials

Biophysicochemical approaches to the solution of nanotechnology problems associated with the design of functional biomimetic nanosystems, hybrid and composite nanobiomaterials and study of their structure-function relationships. The results of studies concerned with physicochemical mechanisms of the formation of organized biomimetic nanostructures and bioinorganic nanomaterials in systems involving a bulky liquid phase and the interface (gas-liquid, solid-liquid, liquid-liquid)during the synthesis and structure formation with the participation of the components of colloid systems, inorganic nanoparticles of various composition and clusters of metals, surfactants, polyelectrolytes and their complexes are discussed. In the development of the methods for the formation of composite bioinorganic nanosystems containing inorganic nanocomponents, two major approaches were used: adsorption and incorporation into the biomolecular matrix or colloid system of presynthesized inorganic nanoparticles, as well as the synthesis of the inorganic nanophase immediately in the biomolecular system. The methods of obtaining biomaterials and nanosystems are based on the principles of biomimetics, biomineralization, self-assembly and self-organization, combination and integration of a number of synthetic and physicochemical methods (physical and chemical adsorption, Langmuir technique, the formation of polycomplexes, chemical linking, competitive interactions, and substitution of ligands in supramolecular and coordination complexes) and nanocomponents of different nature. In particular, a novel approach to the preparation of highly organized nanofilm materials was developed, which is based on the effect of self-assembly and self-organization of colloid nanoparticles during the formation of their complexes with polyfunctional biogenic ligands in the volume of the liquid phase in the absence of any surfaces and interfaces. The physical and chemical factors responsible for the formation of structurally ordered biomolecular and composite nanosystems including nano-sized components of different nature and the possibilities to control the composition, structure, and properties of resulting nanomaterials and nanosystems are discussed. The experimental methods and approaches developed may be useful in studies of structure-property relationships and basic mechanisms of structural organization and transformation at the nanoscales level in biological, artificial, and hybrid nanosystems. The problems of practical application of the synthetic methods and the corresponding nanomaterials are discussed.     

Lignification and cell wall thickening in nodes of Phyllostachys viridiglaucescens and Phyllostachys nigra

BACKGROUND AND AIMS: Bamboos are among the most important plants in the world. The anatomical structure and mechanical properties of the culm internode are well documented. Fewer details are available of the culm node. The aim of this study was a topochemical investigation on lignification and cell wall thickening in developing and maturing bamboo nodes. The deposition sequence and distribution of lignin structural units and cell wall thickening in different anatomical regions of the node of Phyllostachys viridiglaucescens and Phyllostachys nigra are discussed. METHODS: Cell wall thickening and lignification are investigated in the outer part of the nodal region and in the diaphragm of developing and maturing P. nigra culms and in maturing culms of P. viridiglaucescens of different age classes. The lignification during ageing was studied topochemically by means of cellular UV microspectrophotometry. A combination of light microscopy and image analysis techniques were used to measure cell wall thickness. KEY RESULTS: The fibre and parenchyma cell wall thickness does not significantly increase during ageing. In the diaphragm, the cell walls are thinner and the cell diameter is larger than in the outer part of the node. In shoots, the lignin content in the epidermis, hypodermis and in both fibre and parenchyma cells of the diaphragm is relatively low compared with older culms. The fibre and parenchyma cells of the diaphragm have higher values of p-coumaric and ferulic acids than fibre and parenchyma cells of the outer part of the node. CONCLUSIONS: It was hypothesized that the combination of more hydroxycinnamic acids and of thinner cell walls in combination with higher cell diameters (lower density and lower stiffness) in the diaphragm than in the outer part of the node may play an important role in the biomechanical function of the node by acting as a spring-like joint to support the culm by bending forces.     

Comparison of the physiological and biochemical indices of the phagocytosis of ram erythrocytes by macro- and microphages]

Morita and Perkins' method was applied to the study of the stage of ingestion and destruction of an antigen (sheep erythrocytes) in the macrophages of peritoneal exudate of rabbits and rats and in the microphages of rabbit pleural exudate. Ingestion and intracellular destruction of the antigen were accompanied by intensified respiration and glycolysis of phagocytes. Respiration of the three types of phagocytes at two stages of phagocytosis and also the digestive capacity of microphages proved to be sensitive to cyanide and colchicine. The latter failed to influence the ingestion of the antigen by the three types of phagocytes and its digestion by macrophages. The differences in the metabolism routes of macro- and microphages in intracellular destruction of the antigen was postulated. An intensification of the phagocytic activity after the immunization was characteristic of rabbit and rat macrophages.     

不同生态地理区域杉木人工林土壤微生物及生化活性的研究

 本文研究了广西龙胜县里骆林区、宜山县庆远林区、岑溪县七坪林区和田林县老山林区四种不同生态地理区域杉木人工林土壤微生物及其生化活性。研究结果表明：1．土壤微生物的总数及各类群数量均以龙胜县里骆林区和田林县老山林区杉木人工林土壤最高,岑溪县七坪林区次之,宜山县庆远林区最低。2．土壤生化活性包括土壤氮的转化强度,土壤碳的氧化代谢能力和土壤酶活性,也均以龙胜县里骆林区和田林县老山林区杉木人工林土壤最强,岑溪县七坪林区次之,宜山县庆远林区最弱。3．四种不同生态地理区域杉木人工林生长状况与土壤微生物的数量分布和生化活性表现相似规律,龙胜县里骆林区和田林县老山林区杉木人工林林木生长最好,岑溪县七坪林区次之,宜山县庆远林区最差。     

Suitability and limitations of methods for characterisation of activity of malto-oligosaccharide-forming amylases

The suitability and limitations of essential methods and reference substrates used for characterisation of activity of amylolytic enzymes is investigated. Saccharogenic, chromogenic and chromatographic methods are included. The results are discussed in relation to the measurement of reaction rates, determination of action mode and product specificity and the impact on identification and nomenclature of malto-oligosaccharide-forming amylases. An accurate determination of reaction rates using the saccharogenic methods strongly depends on the degree of polymerisation (DP) of the standards used and the hydrolysis products formed by the amylase. Particularly the use of glucose as standard can lead to overestimates due to the differences in the reducing potential of glucose and malto-oligosaccharides. The reliability of the chromogenic methods for determination of action mode depends on the DP of the substrate and the specificity of the amylase. For a characterisation of the starch hydrolysis products and the variation in the DP during hydrolysis, high performance anion-exchange chromatography with pulsed amperometric detection provided a fast and reliable method. A literature survey revealed varying and inconsistent use of nomenclature of malto-oligosaccharide forming amylases. Therefore a systematic approach identifying three main classes of activity is suggested using not only the mode of action and the DP of the major product but also the stage of hydrolysis at which this product is formed.     

洞庭湖景观格局变化及其对水文调蓄功能的影响

景观格局影响并决定着湿地水文调蓄过程和功能。基于洞庭湖区1980、1990、2000和2005年的景观格局数据和相应4年的水文实测数据,利用灰色关联分析,探讨了洞庭湖景观格局变化对水文调蓄功能的影响及其作用机制。结果表明,洞庭湖区景观格局指数与调蓄功能存在不同程度的相关性,其中调蓄量与最大斑块指数和聚合度指数关联度最大,分别为0.77和0.75,说明景观中的优势斑块大小以及同质斑块间的连通性有利于湖区调蓄能力的增加。泥沙沉积率与斑块数、形状指数、多样性指数和均匀度指数关联度也较大,变化于0.7—0.78之间,说明景观的破碎化程度,多样性,形状复杂度的增大会加大湖区泥沙沉积率。分流比、分沙比与景观格局指数的关联度均较小。景观类型指数与调蓄量的关联度分析表明,水田、林地和水体的最大斑块指数和聚合度指数与调蓄量关联度均较高,说明水田、林地和水体最大斑块面积和聚合度的增大有效增大了湖区调蓄能力。     

Pore Waters and the Transformation of Nutrients in Marine Subtidal Sands

The contents of ammonia, nitrites, nitrates, phosphates, and silicates were measured in pore waters of subtidal sands in Vostok Bay, the Sea of Japan. The exchange of nutrients between sand and pore waters was studied in the laboratory using a running-water system while percolating the ground with seawater. The composition of pore waters depended on the method and length of time spent sampling, and also on the distance from the ground surface. Statistical analysis did not reveal stable profiles of nutrient concentrations in sand. The velocities of the release and consumption of nutrients in the experiments were rather low and depended on temperature, length of time spent sampling, duration of measurements, and distance from the sand surface. Release and consumption were connected with absorption and desorption, and were not due solely to the biological process of mineralization of organic matter. Analysis of the data obtained is complicated by the canalization of the water flow in the sand and by the consolidation of the sediment during the measurements. The comparison of pore and near-bottom waters makes it possible to hypothesize that the mineralization of organic matter and the release of nutrients into the pore waters occur throughout the whole column of sediment. The mixing of the seawater and groundwater occurs as a result of advection processes, the most important of which is wave percolation.