Infloreszenz- und Blütenentwicklung bei der KugeldistelEchinops exaltatus (Asteraceae)

InEchinops the flowers are surrounded by several scales and initiated in an acropetal and spiral succession on a cone-like inflorescence axis (Figs. 1–6). The floral organs originate in the following sequence: petals—stamens—carpels—pappus. The petals arise from a meristematic rim and therefore are already interconnected when they arise as primordia. This sympetalous zone remains rather inconspicuous for a long period, but eventually, the elongated corolla tube is formed through intercalary growth in a ring zone. Thereby, the stamens are moved upwards and form ledges on the corolla tube (Fig. 34). In the inferior ovary the usual zones of the typical angiospermous gynoecium can be distinguished, namely a synascidiate, symplicate and hemisymplicate zone. The ovule is borne on carpellary tissue.

     

β-Adrenoceptors in the Tree Shrew Brain. I. Distribution and Characterization of [125I]Iodocyanopindolol Binding Sites

1. The number and distribution pattern of -adrenergic receptors in the brain have been reported to be species specific. The aim of the present study was to describe binding of the -adrenoceptor ligand [¹²⁵I]iodocyanopindolol in the brain of the tree shrew (Tupaia belangeri), a species which provides an appropriate model for studies of psychosocial stress and its consequences on central nervous processes.2. ¹²⁵I-Iodocyanopindolol (¹²⁵ICYP) labeling revealed a high degree of nonspecific binding, which was due mainly to interactions of this ligand with serotonin binding sites. For a quantitative evaluation of ₁- and ₂-adrenoceptors, serotonin binding sites had to be blocked by 100 M 5HT.3. Binding of the radioligand to ₁- and ₂-adrenoceptors was characterized using the ₁-specific antagonist CGP20712A and the ₂-specific antagonist ICI118.551. ₁-adrenoceptor binding is present in the whole brain, revealing low receptor numbers in most brain regions (up to 1.5 to 2.7 fmol/mg). A slight enrichment was observed in cortical areas (lateral orbital cortex: 4.0±0.7 fmol/mg) and in the cerebellar molecular layer (8.7±1.0 fmol/mg).4. Competition experiments demonstrated high- and low-affinity binding sites with considerable variations in K _i values for CGP20712A, showing that various affinity states of ₁-adrenoceptors are present in the brain (K _i: 0.61 nM to 67.1 M). In the hippocampus, only low-affinity ₁-adrenoceptors were detected (K _i: 1.3±0.2 M). Since it is known that ¹²⁵ICYP labels not only membrane bound but also internalized -adrenoceptors, it can be assumed that the large population of the low-affinity sites represents internalized receptors which may be abundant due to a high sequestration rate.5. High numbers of ₂-adrenoceptors are present in only a few brain structures of tree shrews (external layer of the olfactory bulb, 15.8±2.0 fmol/mg; claustrum, 19.3±1.5 fmol/mg; anteroventral thalamic nucleus, 19.4±1.5 fmol/mg; cerebellar molecular layer, 55.0±4.3 fmol/mg). Also for this class of -adrenoceptors, high- and low-affinity binding sites for the ₂-selective antagonist ICI118.551 were observed, indicating that ¹²⁵ICYP labels membrane bound and internalized ₂-adrenoceptors. Only in the cerebellar molecular layer was a high percentage of high-affinity ₂-adrenoceptors detected (K _i for ICI118.551 was 1.8±0.3 nM for 90% of the receptors).6. In conclusion, ₁- and ₂-adrenoceptor binding can be localized and quantified by in vitro receptor autoradiography in the brains of tree shrews when serotonergic binding sites are blocked. Modulatory effects of long-term psychosocial conflict on the central nervous -adrenoceptor system in male tree shrews are described in the following paper.     

Immunohistochemical localization of FSH and LH in the pars distalis of vervet (Cercopithecus aethiops) and babbon (Papio hamadryas) pituitaries

Summary Antisera against oLH¹, oLH and hFSH were used to localize gonadotropic cells in the pars distalis of Cercopithecus aethiops and Papio hamadryas. Three separate cell types were observed for FSH and LH: 85% of immunohistochemically identified gonadotropic cells reacted to all the various antisera; 10% reacted with the anti-LH antibody only; and 5% with the anti-hFSH antibody only. Comparisons between adjacent serial sections treated with various antisera, other than anti-gonadotropic hormones, demonstrated that the gonadotropic cells of these monkeys did not respond to these antisera.

---

Résumé Des anticorps anti-LH ovine, anti-LH ovine et anti-FSH humaine ont été utilisés pour localiser les cellules gonadotropes dans la pars distalis de l'hypophyse des Singes Cercopithecus aethiops et Papio hamadryas. Trois catégories cellulaires distinctes, réagissant avec des anticorps anti-hormones gonadotropes, ont été observées. 85% des cellules immunoréactives identifiées en tant que cellules gonadotropes réagissent simultanément avec les différents anticorps mentionnés; 10% des cellules gonadotropes réagissent seulement avec l'anticorps anti-oLH et 5% de ces cellules seulement avec l'anticorps anti-hFSH. La comparaison avec des coupes adjacentes traitées par divers anticorps autres que les anticorps anti-gonadotropines prouve que les cellules gonadotropes de ces Singes ne réagissent jamais simultanément avec l'un ou l'autre de ces anticorps.

---

Abbreviations used in this Article oLH ovine luteinizing hormone - hFSH human follicle stimulating hormone - ACTH corticotropin - GH growth hormone - LPH lipotropin - TSH thyrotropin     

Expression of fungal thermotolerant endo-1,4-β-glucanase in transgenic barley seeds during germination

The malting quality of two barley cultivars, Kymppi and Golden Promise, was modified to better meet the requirements of the brewing process. The egl1 gene, coding for fungal thermotolerant endo-1,4--glucanase (EGI, cellulase), was transferred to the cultivars using particle bombardment, and transgenic plants were regenerated on bialaphos selection. Integration of the egl1 gene was confirmed by Southern blot hybridization. The transgenic seeds were screened for the expression of the heterologous EGI. Under the high-pI -amylase promoter, the egl1 gene was expressed during germination. The heterologous enzyme was thermotolerant at 65 °C for 2 h, thus being suitable for mashing conditions. The amount of heterologous EGI produced by the seeds (ca. 0.025% of soluble seed protein), has been shown to be sufficient to reduce wort viscosity by decreasing the soluble -glucan content. A decrease in the soluble -glucan content in the wort improves the filtration rate of beer.     

Production of a novel syrup containing neofructo-oligosaccharides by the cells of Penicillium citrinum

A novel syrup containing neofructo-oligosaccharides was produced from sucrose (Brix 70) by whole cells of Penicillium citrinum. The efficiency of fructo-oligosaccharides production was more than 55% and those of the main carbohydrate components, 1-kestose (Fruf 21Fruf 21 Glc), nystose (Fruf 21Fruf 21 Fruf 21 Glc) and neokestose (Fruf 26 Glc12 Fruf), were 22, 14 and 11%, respectively.     

Further cytogenetic analyses of the Croatian triploid shallot “Ljutika” (Allium cepa var.viviparum, Alliaceae) and its comparison with the Indian triploid “Pran”

Feulgen and silver-stained karyotypes and meiosis of two triploid viviparous onion forms (Allium cepa var.viviparum), the Croatian Ljutika and the Indian Pran, were comparatively analyzed. The results of chromosome measurements show that Ljutika and Pran are karyologically not identical, although significant similarities were found in the morphology of their chromosomes. Five geographically distant clones of Ljutika showed good agreement in the number and gross morphology of the chromosomes and in the number and position of NORs and interphase nucleoli. Heterotrivalents were predominant in meiosis of Ljutika but a relatively high frequency of higher multivalents together with univalents and bivalents were also observed. The relationship between Ljutika and Pran and their possible origin are discussed.     

Synthesis ofNeoglycoproteins containing the 3,6-di-O-methyl-β-d-glucopyranosyl epitope and their use in serodiagnosis of leprosy

A stratagem for the synthesis ofneoglycoproteins suitable for the selective serodiagnosis of leprosy is described in which synthetic 3,6-di-O-methyl--d-glucopyranose, the epitope of phenolic glycolipid I fromMycobacterium leprae, was used. Condensation of 8-methoxycarbonyloctanol with the acetobromo derivative of 3,6-di-O-methylglucose gave 8-methoxycarbonyloctyl 2,4-di-O-acetyl-3,6-di-O-methyl--d-glucopyranoside in 65% yield, and with absolute stereospecificity for the anomer. The deacylated product was converted to the crystalline hydrazide and coupled to bovine gamma globulin, bovine serum albumin and poly-d-lysinevia intermediate acyl azide formation to produce the 8-carbonyloctyl 3,6-di-O-methyl--d-glucopyranosyl polypeptides. Theneoglycoproteins were highly sensitive in ELISA and emulated the specificity of the native glycolipid in analysis of sera from patients throughout the spectrum of leprosy and from different geographical regions. The 8-carbonyloctyl 3,6-di-O-methyl--d-glucopyranoside-bovine serum albumin was also synthesized and shown to have about one-half the activity of the -linkedneoglycoprotein. A different synthetic approach produced the 8-carbonyloctyl 4-O-(3,6-di-O-methyl--d-glucopyranosyl)--l-rhamnopyranoside-bovine serum albumin which was also highly sensitive and specific for the serodiagnosis of leprosy. The presence of the second sugar unit, similar to that in the native glycolipid but for the absence ofO-methyl groups, seemed to provide a probe with greater felicity for the serological detection of tuberculoid leprosy.Thus, the results indicate that highly sensitive and specific antigen probes for the serodiagnosis of leprosy can be constructed based only on the terminal one or two sugars of phenolic glycolipid I, and the synthetic approach leads to the formation of haptens with absolute stereospecificity.Nomenclature BGG bovine gamma globulin - PGL-I phenolic glycolipid I - PDL poly-d-lysine - PBS phophate-buffered saline - 3,6-Me₂-Glc-Link-BSA 8-carbonyloctyl 3,6-di-O-methyl-glucopyranoside-bovine senalbumin - 3,6-Me₂-Glc-Rha-Link-BSA 8-carbonyloctyl 4-O-(3,6-di-O-methyl--d-glucopyranosyl)--l-rhan pyranoside-BSA     

Nuclear Overhauser effect investigation on GM1 ganglioside containingN-glycolyl-neuraminic acid (II3Neu5GcGgOse4Cer)

The conformational properties of the oligosaccharide chain of GM1 ganglioside containingN-glycolyl-neuraminic acid, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer, were studied through NMR nuclear Overhauser effect investigations on the monomeric ganglioside in dimethylsulfoxide, and on mixed micelles of ganglioside and dodecylphosphocholine in water. Several interresidual contacts for the trisaccharide core--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-were found to fix the relative orientitation of the three saccharides, while the glycosidic linkage of the terminal -Gal-was found to be quite mobile as the -Gal-(1-3)--GalNAc-disaccharide exists in different conformations. These results are similar to those found for two GM1 gangliosides containingN-acetyl-neuraminic acid and neuraminic acid [1].Abbreviations Ganglioside nomenclature is in accordance with Svennerholm [23] and the IUPAC-IUB Recommendations [24] GM3(Neu5Ac) II³Neu5AcLacCer, -Neu5Ac-(2-3)--Gal-(1-4)--Glc-(1-1)-Cer - GM3(Neu5Gc) II³Neu5GcLacCer, -Neu5Gc-(2-3)--Gal-(1-4)--Glc-(1-1)-Cer - GM1(Neu5Ac) II³Neu5AcGgOse₄Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer - GM1(Neu5Gc) II³Neu5GcGgOse₄Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu5Gc-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer - GM1(Neu) II³NeuGgOse₄Cer, -Gal-(1-3)--GalNAc-(1-4)-[-Neu-(2-3)]--Glc-(1-1)-Cer - GD1a IV³Neu5AcII³Neu5AcGgOse₄Cer, -Neu5Ac-(2-3)--Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer - GalNAc-GD1a IV⁴GalNAcIV³Neu5AcII³Neu5AcGgOse₄Cer, -GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-3)--GalNAc-(1-4)-[-Neu5Ac-(2-3)]--Gal-(1-4)--Glc-(1-1)-Cer - Neu neuraminic acid - Neu5Ac N-acetyl-neuraminic acid - Neu5Gc N-glycolyl-neuraminic acid - Cer ceramide     

Control of glycoprotein synthesis: substrate specificity of rat liver UDP-GlcNAc:Manα3R β2-N-acetylglucosaminyl-transferase I using synthetic substrate analogues

UDP-GlcNAc: Man3R 2-N-acetylglucosaminyltransferase I (GlcNAc-T I; EC 2.4.1.101) is the key enzyme in the synthesis of complex and hybrid N-glycans. Rat liver GlcNAc-T I has been purified more than 25,000-fold (M _r 42,000). TheV _max for the pure enzyme with [Man6(Man3)Man6](Man3)Man4GlcNAc4GlcNAc-Asn as substrate was 4.6 µmol min^–1 mg^–1. Structural analysis of the enzyme product by proton nuclear magnetic resonance spectroscopy proved that the enzyme adds anN-acetylglucosamine (GlcNAc) residue in 1–2 linkage to the Man3Man-terminus of the substrate. Several derivatives of Man6(Man3)Man-R, a substrate for the enzyme, were synthesized and tested as substrates and inhibitors. An unsubstituted equatorial 4-hydroxyl and an axial 2-hydroxyl on the -linked mannose of Man6(Man3)Man-R are essential for GlcNAc-T I activity. Elimination of the 4-hydroxyl of the 3-linked mannose (Man) of the substrate increases theK _M 20-fold. Modifications on the 6-linked mannose or on the core structure affect mainly theK _M and to a lesser degree theV _max, e.g., substitutions of the Man6 residue at the 2-position by GlcNAc or at the 3- and 6-positions by mannose lower theK _M, whereas various other substitutions at the 3-position increase theK _M slightly. Man6(Man3)4-O-methyl-Man4GlcNAc was found to be a weak inhibitor of GlcNAc-T I.Abbreviations BSA Bovine serum albumin - Bn benzyl - Fuc, F l-fucose - Gal, G d-galactose - GalNAc, GA N-acetyl-d-galactosamine - Glc d-glucose - GlcNAc, Gn N-acetyl-d-glucosamine - HPLC high performance liquid chromatography - Man, M d-mannose - mco 8-methoxycarbonyl-octyl, (CH₂)₈ COOOCH₃ - Me methyl - MES 2-(N-morpholino)ethanesulfonate - NMR nuclear magnetic resonance - PMSF phenylmethylsulfonylfluoride - pnp p-nitrophenyl - SDS sodium dodecyl sulfate - T transferase - Tal d-talose - Xyl d-xylose; - {0, 2 + F} Man6 (GlcNAc2Man3) Man4GlcNAc4 (Fuc6) GlcNAc - {2, 2} GlcNAc2Man6 (GlcNAc2Man3) Man4GlcNAc4GlcNAc; M₅-glycopeptide, Man6 (Man3) Man6 (Man3) Man4 GlcNAc4GlcNAc-Asn Enzymes: GlcNAc-transferase I, EC 2.4.1.101; GlcNAc-transferase II, EC 2.4.1.143; GlcNAc-transferase III, EC 2.4.1.144; GlcNAc-transferase IV, EC 2.4.1.145; GlcNAc-transferase V, UDP-GlcNAc: GlcNAc2 Man6-R (GlcNAc to Man) 6-GlcNAc-transferase; GlcNAc-transferase VI, UDP-GlcNAc: GlcNAc6(GlcNAc2) Man6-R (GlcNAc to Man) 4-GlcNAc-transferase; Core 1 3-Gal-transferase, EC 2.4.1.122; 4-Gal-transferase, EC 2.4.1.38; 3-Gal-transferase, UDP-Gal: GlcNAc-R 3-Gal-transferase; blood group i 3-GlcNAc-transferase, EC 2.4.1.149; blood group I 6-GlcNAc-transferase, UDP-GlcNAc: GlcNAc3Gal-R (GlcNAc to Gal) 6-GlcNAc-transferase.     

On the appropriateness of use of a continuous formulation for the modelling of discrete multireactant systems following Michaëlis–Menten kinetics

The possibility of solving the mass balances to a multiplicity of substrates within a CSTR in the presence of a chemical reaction following Michaelis-Menten kinetics using the assumption that the discrete distribution of said substrates is well approximated by an equivalent continuous distribution on the molecular weight is explored. The applicability of such reasoning is tested with a convenient numerical example. In addition to providing the limiting behavior of the discrete formulation as the number of homologous substrates increases, the continuous formulation yields in general simpler functional forms for the final distribution of substrates than the discrete counterpart due to the recursive nature of the solution in the latter case.List of Symbols C{N. M} mol/m³ concentration of substrate containing N monomer residues each with molecular weight M - {N, M} normalized value of C{N. M} - C {M} mol/m³ da concentration of substrate of molecular weight M - _in normalized value of C {M} at the i-th iteration of a finite difference method - {M} normalized value of C {M} - C ₀{N.M} mol/m³ inlet concentration of substrate containing N monomer residues each with molecular weight M - {N ·M} normalized value of C₀{N. M} - _{0 i} normalized value of C ₀ {M} at the i-th iteration of a finite difference method - C ₀ {M} mol/m³ da initial concentration of substrate of molecular weight M - C _tot mol/m³ (constant) overall concentration of substrates (discrete model) - C _tot mol/m³ (constant) overall concentration of substrates (continuous model) - D deviation of the continuous approach relative to the discrete approach - i dummy integer variable - I arbitrary integration constant - j dummy integer variable - k dummy integer variable - K _m mol/m³ Michaëlis-Menten constant for the substrates - l dummy integer variable - M da molecular weight of substrate - M normalized value of M - M da maximum molecular weight of a reacting substrate - N number of monomer residues of a reacting substrate - N maximum number of monomer residues of a reacting substrate - N total number of increments for the finite difference method - Q m³/s volumetric flow rate of liquid through the reactor - S inert product molecule - S _i substrate containing i monomer residues - V m³ volume of the reactor - v _max mol/m³ s reaction rate under saturating conditions of the enzyme active site with substrate - v _max{N. M} mol/m³ s reaction rate under saturating conditions of the enzyme active site with substrate containing N monomer residues with molecular weight M - _max{N · M} dimensionless value of v_max{N. M} (discrete model) - _max{M} dimensionless value of v _max {M} (continuous model) - mol/m³ s molecular weight-averaged value of v_max (discrete model) - mol.da/m³s molecular weight-averaged value of v_max (continuous model) - v _max {M} mol.da/m³s reaction rate under saturating conditions of the enzyme active site with substrate with molecular weight M - _max {M} dimensionless value of v_max{M} - _{max, (i)} dimensionless value of v_max{M} at the i-th iteration of a finite difference method - v _max mol/m³ s reference constant value of v _max Greek Symbols dimensionless operating parameter (discrete distribution) - dimensionless operating parameter (continuous distribution) - M da (average) molecular weight of a monomeric subunit - M selected increment for the finite difference method - auxiliary corrective factor (discrete model)     

α-and β-Glycosidases in maize roots

Four glycosidases were analyzed in 10 mm apical segments prepared from growing roots (15 mm) of Zea mays L. The pH optima were found to be 5.8 for -glucosidase, 4.4 for -galactosidase, 6.4 for -glucosidase and 6.0 for -galactosidase. The -glucosidase showed 4-fold higher activity than the -galactosidase. The distribution of the -glucosidase activity was signifcantly different from that of the -galactosidase, -glucosidase and -galactosidase.Abbreviations -Glu -glucosidase - -Gal -galactosidase - -Glu -glucosidase - -Gal -galactosidase     

Presence of carotenoids in Gordius aquaticus (Nematomorpha,Nemathelminthes) specimens from deep wells

By means of columnar and thin-layer chromatography, the presence of carotenoids in Gordius aquaticus L. (Nematomorpha, Nemathelminthes) from deep wells was studied.The investigations revealed the presence of the following carotenoids: -carotene, mutatochrome, -cryptoxanthin, ,-carotene epoxide,lutein, zeaxanthin and astaxanthin ester.     

Transmission of plastids by pollen in Antirrhinum majus

Summary Up to now Antirrhinum was classified as a typical example for a uniparentalmaternal inheritance of the plastids. However, the findings reported here prove that also the male gametophyte of Antirrhinum may occasionally transmit plastids into the egg. This conclusion is based on genetic experiments involving a form of the plastom mutant prasinizans which is described as gelbgrüne prasinizans. In contrast to all other plastid mutations known in Antirrhinum majus this mutant originated in Sippe 50 is completely viable. In plants containing plastids of this mutant type only, the mutant character is manifested during early growth stages. Cotyledons and first foliage leaves which are initially white or white yellow, slowly turn green and become indistinguishable from normal Sippe 50. Reciprocal crosses of green Sippe 50 with gelbgrüne prasinizans gave few variegated descendants; the others were exclusively plants identical with the maternal parent as far as leaf colour is concerned (Table). The variegated individuals cannot be gene mutants since selfing and crossing experiments showed non-mendelian inheritance. Furthermore it could be ruled out that in the cross Sippe 50 x gelbgrüne prasinizans the three variegated descendants represent spontaneous new plastom mutants because the pale tissue in these plants turned green in the same way as the paternal parent. Because of the typical greening of this mutant and since plastid mutations could be ruled out we have to conclude that plastids were transmitted by the pollen parent into the egg. There these plastids multiplied together with the maternal plastids giving rise to the chimeras after sorting-out of the two plastid types. This interpretation is supported by the observation of mixed cells in tissues where the leaf variegation is finely mosaiced. The results were possible only because the plastids of the pollen parent can be unequivocally recognised.     

Phylogenetic relationship of zeins and coixins as determined by immunological cross-reactivity and Southern blot analysis

Zeins from Zea mays L cv. Maya and coixins from Coix lacryma-jobi L. cv. Adlay were fractionated to obtain -, -, and -zein and -, -, and -coixin. The -coixins were composed of 4 polypeptide classes of 27 kDa (C1), 25 kDa (C2), 17 kDa (C4) and 15 kDa (C5) with solubility properties very similar to those of the 22 kDa and 19 kDa -zeins. Like the -zeins, the C1 and C2 -coixins corresponded to 80% of total Coix prolamins. The fraction corresponding to -coixin contained only one protein band of 22 kDa (C3). This coixin fraction has solubility properties similar to those of -zein and represents 15% of the total coixin. The -zein fraction was composed of a major 17 kDa protein band, while the -coixin fraction consisted of a mixture of - and -coixins.Polyclonal antibodies raised against C1 recognized C1 and C2 and cross-reacted strongly with the 22 kDa -zein, as did C4 and C5 antisera. The antiserum against -coixin showed strong cross-reaction with -zein. The homology between coixins and zeins was further investigated by using Southern hybridization analyses. The genomic DNA of maize and Coix were digested with several restriction enzymes and probed with cDNA clones representing 19 and 22 kDa -zeins as well as the 28 and 16 kDa -zeins. The Coix genome showed complex cross-hybridization sequences with the 22 kDa -zein cDNA, while no cross-hybridization was observed with the 19 kDa cDNA clone. The cDNA clone representing the 28 kDa -zein cross-hybridized with only one band of Coix genomic DNA, in contrast to the three bands observed in maize. This same Coix sequence also cross-hybridized with the cDNA clone representing the 16 kDa -zein. The relevance of these findings are discussed in the context of the origin of zein and coixin genes.     

Die Richtungen des Nahrungsflusses im Darmtrakt der Kleinzikade Euscelidius variegatus KBM. (Jassidae)

Zusammenfassung Der Verlauf des Nahrungsflusses im Darmtrakt der Kleinzikade Euscelidius variegatus wird nach Verfütterung von farbstoffhaltiger Nährlösung ermittelt. Es wird der Beweis erbracht, daß die aufgenommene Nahrungsmenge in der Filterkammer geteilt wird und die beiden Anteile den Darmtrakt auf zwei verschiedenen Wegen in Richtung Rektalblase passieren. Ein Anteil der aufgenommenen Nährlösung wird über einen Kurzschlußweg in der Filterkammer sowohl über den Filterkammerdarm als auch über die Kryptonephridien direkt in den Enddarm gepumpt, während die in der Magentasche der Filterkammer verbleibenden Nahrungsanteile über einen langen Verdauungsweg zum After gelangen. Hierbei wird der Magentascheninhalt in den Magen gedrückt. Von dort aus passiert er den Mitteldarm und erreicht über den Enddarm den After. Der Kurzschlußweg und der Verdauungsweg können gleichzeitig benutzt werden. Der Kurzschlußweg wird von der Nahrung jedoch in viel kürzerer Zeit durchströmt als der längere Verdauungsweg.

---

The directions of the flow of food in the alimentary trad of the leafhopper Euscelidius variegatus KBM. (Jassidae)

Summary The leafhopper Euscelidius variegatus is fed with synthetic food, coloured with 1% Azorubin-S. Its flow in the alimentary tract has been studied. It has been found that the sucked-in food is divided into two parts in the filter chamber, each taking different way in the alimentary tract for its flow. One part of the food is pumped into the hindgut via the short circuit way going through the filter chamber once over the Filterkammerdarm and also over the kryptonephries. That part of the food, which remains in the pocket of the filter chamber takes the long digestion way to the anus over stomach, midgut and hindgut. Both the ways could be used at the same time. But the food takes much shorter time for its passage through the short circuit way as compared to the time needed for the long digestion way.

     

Molecular evolution of the nicotinic acetylcholine receptor: An example of multigene family in excitable cells

An extensive phylogenetic analysis of the nicotinic-acetylcholine-receptor subunit gene family has been performed by cladistic and phenetic methods. The conserved parts of amino acid sequences have been analyzed by CLUSTAL V and PHYLIP software. The structure of the genes was also taken in consideration. The results show that a first gene duplication may have occurred before the appearance of Bilateria. Three subfamilies then appeared: I-the neuronal -bungarotoxin binding-site subunits (7, 8); III-the neuronal nicotinic subunits (2–6, 2–4), which also contain the muscle acetylcholine-binding subunit (1); and IV—the muscle non- subunits (1, , ). The Insecta subunits (subfamily II) could be orthologous to family III and IV. Several tissular switches of expression from neuron to muscle and the converse can be inferred from the extant expression of subunits and the reconstructed trees. The diversification of the neuronal nicotinic subfamily begins in the stem lineage of chordates, the last duplications occurring shortly before the onset of the mammalian lineage. Such evolution parallels the increase in complexity of the cholinergic systems.Abbreviations -Bgt -bungarotoxin - ACh acetylcholine - MP maximum of parsimony - MYA million years ago - NJ neighbor-joining - nAChR nicotinic acetylcholine receptor Correspondence to: N. Le Novère     

Factors shaping Ernst Mayr's concepts in the history of biology

Conclusion As frequently pointed out in this discussion, one of the most characteristic features of Mayr's approach to the history of biology stems from the fact that he is dealing to a considerable degree with his own professional history. Furthermore, his main criterion for the selection of historical episodes is their relevance for modern biological theory. As W. F. Bynum and others have noted, the general impression of his reviewers is that one of the towering figures of evolutionary biology has now written a towering history of his discipline.¹³⁸ Bynum is here referring to The Growth of Biological Thought, but this observation holds equally true for Mayr's other historical writings: One must surely read this book [One Long Argument] not only for its content in itself, but for what it tells of its author. And certainly as one does so, one comes away full-handed. Many, if not all, of the disputes and controversies that have driven Mayr through his long intellectual life reappear, stated as forcefully and elegantly as ever.¹³⁹ Up to this point, most reviewers agree; the bone of contention is, rather, how to evaluate Mayr's historical work, considering this observation. The two related characteristics of his work-I will call them subjectivity and presentism-stand in opposition to a widespread approach in the history of science exemplified by Kuhn's suggestion that insofar as possible..., the historian should set aside the science that he knows. His science should be learned from the textbooks and journals of the period he studies.¹⁴⁰ There are, however, historians who consider the close connection between Mayr and the subject matter of his historical studies to be an advantage.¹⁴¹ On the other hand, it is assumed that the connection between past and present must result in a distortion of the historical truth and lead to a historiographical fallacy, commonly referred to as Whig history. Herbert Butterfield, who in 1931 gave the term its now generally accepted meaning, believed that real historical understanding is not achieved by the subordination of the past to the present, but rather by our making the past our present and attempting to see life with the eyes of another century than our own¹⁴². Unfortunately, Butterfield's definition of what he considers Whig history remains somewhat vague, and modern authors have emphasized what they consider most important. Butterfield's subordination of the past to the present is referred to in respect to the selection of subjects (there are more biographies of Charles Darwin than of, let's say, Louis Agassiz),¹⁴³ to the evaluation of historical authors,¹⁴⁴ or, more generally, to all kinds of histories with one eye, so to speak, upon the present.¹⁴⁵ The underlying tendency of Whig historians is to produce a historical account told from the viewpoint of those in power,¹⁴⁶ leading to a glorification of the present.¹⁴⁷ It is obvious that Mayr's strongly presentist approach to the history of biology can be called Whiggish, if we apply the criteria of selection or reference. However, it might be worth mentioning that the program of writing a strictly historicist account of the history of science is challenged by various authors.¹⁴⁸ For Mayr, it is not only legitimate but necessary to compare the present situation with the past. Whiggish is only the evaluation of an author in terms of our time.¹⁴⁹ I cannot discuss the Whit/anti-Whig controversy in any detail here, apart from saying that Mayr has defended himself rather extensively against the charges of being Whiggish.¹⁵⁰ Nevertheless, it may be useful to touch on some of the criticisms that are predominant in reviews of his writings. First, we encounter the notion that historians can write a true and convincing historical account only if they have no personal interest or interpretation of their own; Mayr, on the other hand, because he has such strong interpretations of his own, ... cannot possibly convince everyone that he is right about everything.¹⁵¹ It makes one wonder, what historian has ever been able to convince everyone that he or she is right about everything? But apart from this peculiar idea, it unquestionably poses certain dangers if the subject matter of historical scrutiny and the author are identical. At the same time, this identity brings certain advantages with it, especially firsthand experiences of the period in discussion. Whether these personal memories ultimately result in a distorted picture of the past has to be decided in every particular instance. The notion that a scientific study can be conducted by a completely detached observer from a neutral standpoint has been shown to be impossible in physics, and it is also an illusion in historiography. The question is not whether, but which kind of interest are the underlying motivation for a historian. At this point, Mayr is ahead of his critics when he suggests that our understanding of the past always has a subjective component: The main reason, however, why histories are in constant need of revision is that at any given time they merely reflect the present state of understanding; they depend on how the author interpreted the current zeitgeist of biology and on his own conceptual framework and background. Thus, by necessity the writing of history is subjective and ephemeral.¹⁵² Second, the temporal proximity between the event and the historical analysis makes difficulties inevitable and will finally result in certain false assessments. But this applies to all historians when they discuss recent problems, regardless of whether they are personally involved or not: As long as the battle between Darwinism and Lamarckism was raging, it was quite impossible to undertake an unbiased evaluation of Lamarck. ...[The] definite refutation of Lamarck's theory of evolutionary causation clears the air. We can now study him without bias and emotion and give him the attention that this major figure in the history of biology clearly deserves.¹⁵³ Third, Mayr is primarily interested in biological problems and not, for instance, historiographical, sociological, or psychological questions. Several authors have remarked that since the beginning of the professionalization of the history of science in the 1960s, a rift between two groups has developed, resulting from the heterogeneous professional backgrounds and interests of the people involved: the authors who were originally biologists and became interested in the history of their discipline only later on, and the authors who were trained as historians.¹⁵⁴ Whereas the first group, the biologists, tend to be laymen in history proper, the historians are in most cases laymen in biology. Different professional backgrounds obviously shape the historical perspective in both groups, but neither approach is necessarily superior. The great number of important books in the history of biology written by biologist documents how valuable this point of view can be. On the other hand, it cannot be denied that the writings of biologists in the history of science tend to have a strong internalist tendency and often neglect the professional, cultural, and political context of science. Mayr's approach is that of a biologist; it is internalist, and typical for scientists who turn to the history of their discipline.I want to conclude my analysis with a quotation from a review by Douglas J. Futuyma, which gives a perceptive glimpse of Mayr's personality and style: One cannot help standing in awe of the germanic capacity for vast, allembracing synthesis: consider the lifelong devotion of Goethe to Faust, or Wagner's integration of the arts into a Gesamtkunstwerk in which all of human history and experience is wrought into epic myth. It is perhaps in this tradition that Ernst Mayr's The Growth of Biological Thought stands: a history of all of biology, a Ring des Nibelungen complete with leitmotivs such as the failures of reductionism, the struggle of biology for independence from physics, and the liberation of population thinking from the bounds of essentialism.¹⁵⁵ Within this style of thinking Mayr has to offer...nothing less than a vision of biology that places neodarwinian evolutionary theory firmly at the centre.¹⁵⁶ There may be other visions of biology, but few of them have as indefatigable and able representatives as Darwinism has in Ernst Mayr.     

O-Glycosylhydrolases of Marine Filamentous Fungi: β-1,3-Glucanases of Trichoderma aureviride

The ability to produce extracellular O-glycosylhydrolases was studied in 14 strains of marine filamentous fungi sampled from the bottom sediments of the South China Sea. The following activities were detected in the culture liquids of the fungi: N-acetyl--D-glucosaminidase, -D-glucosidase, -D-galactosidase, -1,3-glucanase, amylase, and pustulanase. -1,3-Glucanases were isolated by ultrafiltration, hydrophobic interaction chromatography, and ion exchange chromatography, and their properties were studied. Data on products of enzymatic digestion of laminaran, absence of transglycosylation activity, and the pattern of action of natural inhibitors confirmed that -1,3-glucanase belonged to the exo type. Inhibitor analysis demonstrated the role of a thiol group and tryptophan and tyrosine residues in the catalytic activity.     

5′-AMP hydrolysis by suspensions and homogenates of pancreatic islet cells from normal and cortisone-treated rats

Summary Suspensions of endocrine pancreas cells were prepared by shaking collagenase-isolated rat islets of Langerhans in calcium-free buffer. When incubated with 1.0 mM substrate at pH 7.4, the cells split,P _i from 5-AMP at a rate of 87 nmol/h per g DNA, and from-glycerophosphate at a rate of 25 nmol/h per g DNAK _m for 5 AMP was about 54 M. Adenosine or theophylline inhibited the 5-AMP hydrolysis. Homogenization of the cells increased the activity toward 5-AMP by 23% and that toward-glycerophosphate by 115%. Injecting rats with cortisone had no effect on the 5-AMP hydrolysis by whole cells but significantly increased the activity in cell homogenates; the intracellular activity toward 5-AMP was more than doubled by the cortisone treatment. Staining whole islet cells for 5-AMP-splitting activity resulted in a demarcation of the cell periphery in control rats. Cells from cortisone-treated rats showed heavier deposits of reaction product, and their cell periphery did not stand out as clearly. It is suggested that 5-nucleotidase is largely an ectoenzyme in normal rat islet cells. The cells also contain an as yet unidentified intracellular phosphatase that seems to be solely responsible for the increased hydrolysis of 5-AMP in cortisone-treated rats.