The immunocytochemical localization of superoxide dismutase in the enterocytes of the avian intestine: The effect of vitamin D3

Summary Both light microscopical and electron microscopical immunocytochemical techniques were utilized to localize CuZnsuperoxide dismutase (SOD) in the duodenum of normal, rachitic and vitamin-D₃-replete chicks. This enzyme catalyses the dismutation of the superoxide anion, a toxic free radical generated during the normal aerobic metabolism of most respiring cells. Light microscopy showed no SOD activity associated with the duodenal enterocytes of normal and rachitic chicks. However, in rachitic animals subsequently treated with vitamin D, i.e. vitamin-D-replete chicks, intense immunoreactivity for the enzyme was seen in association with the apical border of the duodenal absorptive cells. Immunostaining for SOD was not seen in goblet cells. With electron microscopy, immunostaining for SOD activity was identified in association with the apical microvilli and, to a lesser degree, with the terminal web, a well as in association with both lysosomes and peroxisomes. From this report it appears that there is a physiological relationship between vitamin D, SOD and the intestinal absorptive cell. However, the precise relationship must await further clarification.     

Chlorierte Kohlenwasserstoffe in Brutv?geln aus dem Binnenland Niedersachsens

Zusammenfassung Rückstände chlorierter Kohlenwasserstoffe in Eiern und Lebern von im Binnenland Niedersachsens brütenden Vogelarten — Feldsperling, Mehlschwalbe, Weißstorch, Graureiher, Saatkrähe, Stockente und andere Arten — werden angegeben und deren Abhängigkeit von Brutort, Nahrung und Zugverhalten diskutiert.

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Chlorinated hydrocarbons of some bird species breeding in the inland of Lower Saxony (FRG)

Summary Residues of chlorinated hydrocarbons in eggs and livers of some bird species — Tree Sparrow, House Martin, White Stork, Heron, Rook, Mallard, and further species — are presented. The dependence on place of breeding, food web, and migration is discussed.

     

Degradation of 3-chlorobiphenyl by in vivo constructed hybrid pseudomonads

Abstract 3-Chlorobiphenyl-degrading bacteria were obtained from the mating between Pseudomonas putida strain BN10 and Pseudomonas sp. strain B13. Strains such as BN210 resulted from the transfer of the genes coding the enzyme sequence for the degradation of chlorocatechols from B13 into BN10, whereas B13 derivatives such as B131 have acquired the biphenyl degradation sequence from BN10. During growth of the hybrid strains on 3-chlorobiphenyl 90% chloride was released. Activities of phenylcatechol 2,3-dioxygenase, benzoate dioxygenase, catechol 1,2-dioxygenase, chloromuconate cyloisomerase and 4-carboxymethyl-enebut-2-en-4-olide hydrolase were found in 3-chlorobiphenyl-grown cells. The hybrid strains were found to convert some congeners of the Aroclor 1221 mixture such as mono- and dichloro-substituted biphenyls.     

Plant regeneration by organogenesis in Vitis rootstock species

A procedure for the regeneration of Vitis rootstocks plantlets by organogenesis from foliar tissues is described. Leaves from mature plants grown in growth chambers or from plantlets grown in tubes were wounded with a scalpel and cultured on a modified Murashige and Skoog liquid medium containing different concentrations of benzyl-aminopurine. The presence of benzyl-aminopurine is required for shoot formation. The age of the source explant, the composition of the culture medium and the culture temperature are important parameters of the regeneration process.Abbreviations BA 6-benzyl-aminopurine - MS Murashige and Skoog medium - MM modified Murashige and Skoog medium     

Purification of acetyl-CoA: 17-O-deacetylvindoline 17-O-acetyltransferase from Catharanthus roseus leaves

The enzyme acetyl-CoA: 17-O-deacetylvindoline 17-O-acetyltransferase which terminates vindoline biosynthesis has been isolated from Catharanthus roseus leaves, further characterized and purified to homogeneity by three step column chromatography and subsequent preparative isoelectric focusing. Kinetic properties concerning the enzyme reaction are discussed. Five multiple forms of the acetyl-transferase could be observed, each consisting of two subunits. This enzyme is now the best characterized of the enzymes involved in vindoline biosynthesis.Abbreviations DTE dithiothreitol - EDTA ethylenediamine-tetraacetic acid - HEPES N-(2-hydroxyethyl)-piperazine-N-2-ethanesulfonic acid - IEF isoelectric focusing - KP_i potassium phosphate - M_r rel.molecular mass - PEG polyethylene glycol - SDS-PAGE sodium dodecylsulfate polyacrylamide gel electrophoresis - Tris 2-amino-2-(hydroxymethyl)-1,3-propandiol     

Pollination Ecology of Pedicularis punctata Decne. (Scrophulariaceae) in the Kashmir Himalaya

Abstract The pollination ecology of Pedicularis punctata was studied in the Pir Panjal Range of the Kashmir Himalaya in the summer of 1989. Its nectarless, rostrate, long-tubed flower was found to be pollinated exclusively by Bombus foragers vibrating pollen while the stigma contacted pollen in the pollinator's cervical crevice. Workers of Bombus tunicatus and B. flavothoracicus comprised 95% of its pollinators. Pollen-foraging fidelity of its pollinators was greatest where diversity of Bombus -pollinated plant species in three plant communities was least. Foragers on other plants carried virtually no Pedicularis pollen. P. punctata is a mid-season blooming species similar in its pollination syndrome to comparable species in other geographic regions. The enigmatic function of its long, nectarless corolla tube, even more exaggerated in other Asiatic species, requires further investigation.     

Karyological stability and microevolution of a cell suspension culture ofBrachycome dichromosomatica (Asteraceae)

A long-term suspension culture ofBrachycome dichromosomatica (2n = 4) was induced from a cotyledon-derived callus. Subcultures were obtained every week up to three years. The bulk of the cultures displayed a stable diploid karyotype, while one cell line evolved with 2n = 5 chromosomes in the 86th reinoculation. No further chromosomal change occurred also in that cell line. It is assumed that the fifth chromosome is the expression of a trisomy 2.The chromatin ultrastructure was of the species-specific chromomeric type in the wild-type line, while the trisomic line displayed more condensed chromatin, what probably indicates a rather inactive state of the extra-chromosome.Brachycome dichromosomatica is suggested to represent an ideal species to follow-up karyotype stability and/or variation in cell culture.As a former student W. N. dedicates this paper in gratitude and admiration to Prof. DrElisabeth Tschermak-Woess on the occasion of her 70th birthday. Prof.Woess with her scientific work has stimulated in an unique manner the study of nuclear structures in plants, of endopolyploidy and polytene chromosomes, and has thus established the basis for the rapidly increasing research in these fields.     

Characterization of two β-glucosidase genes fromClostridium thermocellum

Summary Two -glucosidase genes, designatedbglA andbglB, were isolated from a gene bank ofClostridium thermocellum DSM 1237. The coding sequences forbglA andbglB were located on non-homologous DNA fragments of 3.2– and 3.4-kb, respectively. Both genes direct inEscherichia coli the synthesis of cytoplasmic -glucosidases, which differ with respect to substrate specificity and temperature profile. The properties of thebglA-encoded -glucosidase A closely resemble that of a -glucosidase previously isolated fromC. thermocellum cultures.     

Isolation of aClostridium thermocellum gene encoding a thermostable β-1, 3-glucanase (laminarinase)

Summary AClostridium thermocellum gene directing the synthesis of a thermostable -glucanase was localized on a 1.9-kb DNA fragment by subcloning intoEscherichia coli plasmid vectors. The enzyme was highly efficient in degrading glucans with alternating -1, 3- and -1,4-linkages such as lichenan and barley glucan. It was also active towards the -1, 3-glucan laminarin, but lacked activity on cellulosic substrates and -glucans. The enzyme was therefore classified as -1, 3-glucanase (laminarinase) and the corresponding gene was designatedlicA. With barley -glucan as substrate the enzyme had a pH optimum around pH 6.5 and a temperature optimum at 65°C. It was stable for several hours at 60°C in the absence of substrate.     

Purification and properties of an extracellular β-glucosidase from the cellulolytic thermophile Clostridium stercorarium

Summary Clostridium stercorarium cultures grown on cellobiose contain both an extracellular and a cell-bound -glucosidase activity. A substantial portion of the cell-bound enzyme could be extracted by osmotic shock, suggesting a periplasmic localization. The -glucosidase present in culture supernatants was purified to homogeneity. It was found to be identical in all aspects tested with the cell-bound -glucosidase. The enzyme exists as a monomer with an apparent molecular weight of 85.000 (SDS-PAGE) and a pI of 4.8. It shows optimal activity as pH 5.5 and 65° C. Thiol groups are essential for enzyme activity. In the presence of reducing agents and divalent cations the half-life of the purified enzyme was more than 5 h at 60°C. The enzyme hydrolyses at different rates a wide range of substrates including aryl--glucosides, cellobiose, and disordered cellulose. K _m values were determined as 0.8 mM for p-nitrophenyl--glucoside (PNPG) and 33 mM for cellobiose. The cellular localization and the substrate specificity pattern are consistent with a dual role of the C. stercorarium -glucosidase in cellulose saccharification: (1) Cleavage of cellobiose formed by exoglucanase and (2) degradation of cellodextrins produced by endoglucanase action.