Mesoionic pyrido[1,2-a]pyrimidinones: Discovery of triflumezopyrim as a potent hopper insecticide1

A novel class of mesoionic pyrido[1,2-a]pyrimidinones has been discovered with exceptional insecticidal activity controlling a number of insect species. In this communication, we report the part of the optimization program which led to the discovery of triflumezopyrim as a highly potent insecticide controlling various hopper species. Our efforts in discovery, synthesis, structure-activity relationship elucidation, and biological activity evaluation are also presented.     

Wachstumsanomalie an einem Zahn vonProcarcharodon (Selachii,Chondrichthyes) aus den obereozänen Gehlbergschichten von Helmstedt (Niedersachsen)

In the Upper Eocene Gehlberg Formation of Helmstedt, a tooth ofProcarcharodon Casier, 1960 was discovered which shows a distinct anomaly in growth. This anomaly is thought to be the result of a growth hinderance in the germstage of the tooth. The germ of selachian teeth is a hydroskeleton and is situated in the connective tissue at the lower part of the jaws. Since the hydroskeleton of the germ itself was not damaged, the deformed tooth hardened and later on was pushed in its functional position.     

Apoplastic accumulation of iron in the epidermis of maize (Zea mays) roots grown in calcareous soil

High concentrations of Fe in the roots of plants grown in calcareous soil have been found in a variety of plants, which, nevertheless, show Fe deficiency symptoms. In the present work, energy dispersive X-ray (EDX) analysis at the cellular level has been used to characterize high root Fe concentrations in maize ( Zea mays L.) grown in a calcareous soil in comparison with low root Fe concentrations under acidic soil conditions. Roots were thoroughly washed to remove adhering soil particles from the root surface as far as possible. To avoid any interference with possibly still present soil particles, the excitation beam was focused on radial walls of neighboring cells as well as on the symplast. Under alkaline conditions, high Fe concentrations in the m M range and higher accumulated in the epidermal root apoplast. Symplastic Fe was not detectable. Only traces of Fe were detectable in the apoplast of the cortex parenchyma. Under acidic conditions, apoplastic root Fe concentrations were clearly lower than under alkaline conditions, and no Fe was detectable in the root apoplast by use of EDX analysis. We conclude that, under alkaline conditions, high amounts of Fe are trapped in the epidermal root apoplast (apoplastic Fe inactivation), probably because of a high apoplastic pH and thus restricted translocation towards the root stele and to the upper plant parts. In contrast, on acidic soils Fe translocation towards the root stele and thus Fe supply to the upper plant parts was not impaired. Our findings imply that Fe deficiency on calcareous soils is not caused by restricted acquisition of Fe from the soil.     

Ultrastructural and physiological changes in root cells of Sorghum plants (Sorghum bicolor S. sudanensis cv. Sweet Sioux) induced by NaCl

The xerophytic, but salt-sensitive Sorghum cultivar ‘SweetSioux’ is known as an ion excluder with a high K/Na selectivityat the plasmalemma and tonoplast of epidermal root cells. Theaim of this study is the correlation of salt-effected changesin physiological parameters with structural and ultrastructuralchanges in root cells. The investigation was carried out withroot cells because these cells are most directly exposed tothe growth medium. Sorghum bicolor S. sudanensis cv. Sweet Sioux plants weregrown under steady-state conditions on nutrient solutions withor without 40 mol m^–3 NaCl. Sorghum sustained this treatmentbut showed several salt-induced structural and physiologicalchanges which were studied in various cell types of the roottip. (1) NaCl salinity led to a shorter growth region and to salt-inducedalterations in the chemical and physical properties of the cellwalls in the root tips. (2) Salt treatment also increased the membrane surface in rootcells: root cells showed an increase in the quantity of vesiclesin the epidermis and in the middle cortex cells. Additionally,some of the epidermis cells of salt-treated plants revealeda characteristic build-up of transfer cells, suggesting an increasein membrane surfaces to increase the uptake and storage of substances. (3) The number of mitochondria increased in the epidermal andin the cortex cells after salt stress thus indicating an additionalsupply of energy for osmotic adaptation and for selective uptakeand transport processes. (4) In the epidermal cytoplasm NaCl stress led to a significantdecrease of the P, K, Ca, and S concentrations accompanied byan increase of Na concentration. Electron micrographs show anincrease in electron optical contrast within the cytosol andin the matrix of the mitochondria. These results are discussedwith regard to the possibility of influence on the part of metabolicfunctions. (5) The NaCl concentrations were seen to increase and the Kconcentrations to decrease during salt stress in the vacuolesof the epidermis and cortex cells. The salt-induced increasein vacuolar NaCl concentrations of epidermis and cortex cellsare in the region 2 cm behind the root tip, which is sufficientfor an osmotic balance towards the growth medium. Additionalsolutes are necessary 0.5 mm behind the root tip to facilitateosmotic adaptation. The results show ultrastructural changes caused by an Na-avoidingmechanism characterized by a high level of energy consumption.The exclusion of Na from the symplast seems to lead additionallyto a decrease in cytoplasmic concentrations of such essentialelements as Mg, P, S, and Ca and is thus responsible directly(via energy supply in mitochondria, homeostasis, selectivityof K over Na) or indirectly (via enzyme conformation, cytoplasmichydration) for the ultra-structural degradation indicated. Thesalinity-induced multiplicity of structural and functional changeswithin cell compartments constitutes a group of indicators forthe limited NaCl tolerance of Sorghum. Key words: Sorghum bicolor S. sudanensis, ultrastructure, salt tolerance, NaCl, Ca-deficiency     

Beiträge zur kenntnis der symbiontischen einrichtungen der gattung apion HRBST

Ohne ZusammenfassungDissertation der Philosophischen Fakultät der Universität Leipzig.     

Haptenylation of antibodies during affinity purification: a novel and convenient procedure to obtain labeled antibodies for quantification and double labeling

 Haptenylation of primary antibodies is a useful technique for multiple purposes. It is a technically straightforward procedure, as many haptens are available as N-hydroxysuccinimide esters or isothiocyanates. Unfortunately, the hapten group may become covalently attached to or close to the combining site of antibodies, lectins, or other ligand-binding proteins during the process of haptenylation. Thus, the interaction of the corresponding protein with its ligand may become severely hampered. To overcome this restriction, we developed a novel procedure for the haptenylation of polyclonal antibodies that combines purification and haptenylation. Haptenylation during adsorption to the affinity matrix combines two advantages: the antigen binding site is protected and the labeling procedure becomes most convenient, as overlabeled proteins and unreacted haptens are easily removed by simple washing. Haptenylation during adsorption to the affinity matrix is a two-phase reaction, which requires different conditions to the conventional procedure. To obtain such optimal conditions, stabilities and reactivities of N-hydroxysuccinimide esters and isothiocyanate groups were investigated with a newly developed assay. Based on this information, antibodies against two recently described calcium-binding proteins, NCS-1 and NVP-3, were biotinylated or digoxigenylated. The haptenylated antibodies were successfully applied for biochemical determination and simultaneous immunoenzymatic double labeling of the two proteins. Accepted: 9 March 1998