Polysaccharide and protein secretion by grass microhairs

Summary Secretory activities of bicellular microhairs from grasses belonging to the subfamilies Chloridoideae, Arundinoideae, Panicoideae, and Bambusoideae, and including the chloridoid, panicoid and Enneapogon microhair morphological types, have been investigated. Light microscopic histochemistry indicated that all microhairs studied secrete polysaccharide and protein (or glycoprotein), including those which also secrete salt. Localization of polysaccharide at ultrastructural level using periodic acid-thiocarbohydrazidesilver proteinate staining revealed that in panicoid type microhairs dictyosomes are involved in polysaccharide secretion, whereas in the chloridoid and Enneapogon types partitioning membranes seem to be involved instead.Abbreviations Ag silver precipitates representing localization of polysaccharide - BC basal cell - C cuticle - CC cap cell - CH cuticular chamber - CN system of membrane bound channels and vesicles - CP chloroplast - CW cell wall - D dictyosomes - M mitochondria - N nucleus - PTM partitioning membranes - RER rough endoplasmic reticulum - S secretory material - St starch grain - US unstained dictyosome cisternae - V vesicle     

Gibberellins play a role in the interaction between imidazole fungicides and cytokinins in Araceae

Imidazole fungicides such as imazalil, prochloraz, and triflurnizole and the triazole growth retardant paclobutrazol promote the shoot-inducing effect of exogenous cytokinins in Araceae, such as Spathiphyllum floribundum Schott and Anthurium andreanum Schott. The mechanism of their action could partially be based on the inhibition of gibberellic acid (GA) biosynthesis, because administration of GA₃ inhibits the phenomenon completely in S. floribundum. Not only is the suppression of GA biosynthesis involved, but also the metabolism of endogenous cytokinins is significantly altered. Although the balance between isopentenyladenine, zeatin, dihydrozeatin, and their derivatives was shifted to distinguished directions by administration of BA and/or imazalil and/or GA₃, no correlation between these changes in metabolic pathways and the number of shoots could be found. The metabolism of BA was not significantly altered by adding imazalil to the micropropagation medium of S. floribundum.Abbreviations 2,4-D 2,4-dichlorophenoxyacetic acid - [9R-5P]DHZ 9--d-ribofuranosyl-dihydrozeatin-monophosphate - [9R-5P]iP 6-isopentenyl-9--d-ribofuranosyladenine-monophosphate - [9R-5P]Z 9--d-ribofuranosyl-zeatin-monophosphate - [9G]BA 6-benzyl-9--d-glucopyranosyladenine - [9G]DHZ 9--d-glucopyranosyl-dihydrozeatin - [9G]iP 6-isopentenyl-9--d-glucopyranosyladenine - [9G]Z 9--d-glucopyranosyl-zeatin - [9R]BA 6-benzyl-9--d-ribofuranosyladenine - [9R]DHZ 9--d-ribofuranosyl-dihydrozeatin - [9R]iP 6-isopentenyl-9--d-ribofuranosyladenine - [9R]Z 9--d-ribofuranosyl-zeatin - BA 6-benzyladenine - DHZ dihydrozeatin - ES⁺ LC-MS/MS HPLC coupled Electrospray Tandem Mass Spectrometry - f.m. fresh mass - mT 6-(3-hydroxybenzyl)adenine - IMA imazalil - iP isopentenyladenine - NAA 1-naphthalene acetic acid - NFT Nutrient Film Technique - (OG)[9R]DHZ O--glucopyranosyl-9--d-ribofuranosyl-dihydrozeatin - (OG)[9R]Z O--d-glucopyranosyl-9--d-ribofuranosyl-zeatin - (OG)DHZ O--d-glucopyranosyl-dihydrozeatin - (OG)Z O--d-glucopyranosyl-zeatin - PAR Photosynthetic Active Radiation - PBZ paclobutrazol - PRO prochloraz - TDZ thidiazuron - TRI triflurnizole - Z zeatin     

Computerized scheme for the reaction of hemoglobin with ligands

A scheme for the reaction of hemoglobin with ligands is described, which postulates the functional heterogeneity of the chains, considers all possible combinations of the distribution of the ligand on the four chains of hemoglobin, and does not require simplifying assumptions about the hemoglobin reactivity. Ten tetrameric species are considered, together with 16 reactions between these species, each with an on and an off rate constant. The dissociation of hemoglobin tetramers into dimers is also considered, with four on and four off rate constants for the reactions between dimers, and ten equilibrium constants for the reactions between tetramers and dimers. Moreover, some side reactions, such as the trapping of ligands by a hemoglobin competitor, are included. A FORTRAN program, suitable for microcomputers, is described for handling this scheme, with some examples showing its advantages.     

On age morphological changes of males of Chydoridae (Cladocera)

Summary Young and adult males of 11 species of Chydoridae are studied, their figures being published here (fig. 1–15). The necessity is stressed to distinguish young forms of males and gynandromorphic individuals.Pleuroxus balatonicus is considered to be described from the population ofPleuroxus unicatus having under Balaton Lake conditions retarded transformation of young males into adult form, and accordingly having unusually numerous young males. \qO\qs\qn\qo\qv\qn\qy\ye \qr\ye\qz\qu\ql\Qj\qt\qa\qt\qy 11 (. 1–15). . , Pleuroxus uncinatus , Pleuroxus balatonicus.     

Fine structure of early previtellogenic oocytes in Mugil (Liza) auratus Risso, 1810 (Teleostei,Mugilidae)

Summary Sequential cytological events at the onset of previtellogenesis were studied in oocytes from 12 m to 70 m in diameter of golden grey mullet. The main cytological changes observed (increase in size of cell, nucleus, nucleolus and increase in number of nucleoli, RNP particles, nuage and mitochondria) provide evidence for important synthetic processes in an early preparatory phase of oocyte development.Somatic cells (pre-follicle, follicle and thecal) are also described.     

Ongoing ultradian activity rhythms in the common vole,Microtus arvalis,during deprivations of food,water and rest

Summary The timing mechanism underlying ultradian (2–3 h) activity patterns in the common vole, Microtus arvalis, was studied using behavioural deprivation experiments. These were aimed at distinguishing between a homeostatic control mechanism, in which the rhythmic behaviour itself is part of the causal loop, and a clock mechanism, independent of the behaviour.In 175 experiments, deprivation of food during 3 ultradian cycles in (subjective) daytime did not result in significant changes in the ultradian periodicity of attempts to obtain the food, compared with ad lib. access to food and water. A minor, but significant increase in ultradian activity time () occurred in the course of the deprivation, but this was compensated by a shorter ultradian rest (). These results were obtained both in intact animals (n = 24), which showed ultradian and circadian rhythmicity in behaviour, and in animals (n = 21) with electrolytic lesions aimed at the suprachiasmatic nuclei (SCN), which lacked the circadian modulation of behaviour. Simultaneous deprivation of water and food in 8 voles without circadian rhythmicity during 40 experiments also did not lead to any change in the ultradian periodicity of feeding attempts.Rest deprivation was studied in 5 SCN lesioned voles, by forcing running wheel activity to continue following spontaneous running. Thus, the experimental activity bout was artificially lengthened to 2–9 h in 67 experiments. The onset of the subsequent rest episodes occurred independent of the duration of the preceding . The duration of was dependent on the preceding, experimental in a periodic fashion. The interval experimental (=lengthened +following ) was equal to one, two or three times the control (obtained on nonexperimental days). This result fits the prediction of a clock model and is in conflict with a monotonicincrease of with , as expected in a homeostatic, restorative process.It is concluded that the ultradian timing of activity in the common vole can be explained neither by homeostatic hunger or thirst mechanisms nor by homeostatic rest/activity regulation. The results strongly suggest an independent clock system generating ultradian feeding rhythms in the common vole.Abbreviations DD continuous darkness - LD light-dark regime - LL continuous light - RCA retrochiasmatic area - ARC arcuate nucleus - SCN suprachiasmatic nuclei - ultradian period - ultradian activity time - ultradian rest time     

Ganglioside-cholera toxin interactions: a binding and lipid monolayer study

Summary On t.l.c. plates ¹²⁵I-cholera toxin binds to a disialoganglioside tentatively identified as GD_lb with about 10 times less capacity than to ganglioside GM₁. Binding of labeled toxin to both gangliosides was abolished in presence of excess amounts of unlabeled B subunit. Ganglioside extracts from human or pig intestinal mucosa showed toxin binding to gangliosides GM₁ and GD_1b. In ganglioside-containing lipid monolayers the penetration of the toxin was independent of the ganglioside binding capacity.Abbreviations GM₂ Gal-NAc14Gal(3-2NeuAc)14G1c1Cer - GM₁ Gal3Ga1-NAc14Gal(32NeuAc)14G1c11Cer - GD_1a NeuAc23Ga113Gal-NAc14Gal(32NeuAc)14G1c11Cer - GD1b Gall3Gal-NAcl4Gal(32NeuAc82NeuAc)14Glc11Cer - GT_1b NeuAc23Ga113Ga1-NAcal4Gal(3-2NeuAc82NeuAc)14G1c11Cer - dpPC 1,2-hexadecanoyl-sn-glycero-3-phosphocholine - dpPE 1,2-hexadecanoyl-sn-glycero-3-phosphoethanolamine     

β-thalassemia mutations in the Portuguese population

Summary In this study we have carried out haplotype analysis on the -globin gene cluster and characterized the -thalassemia mutation by oligonucleotide hybridization in 14 patients with thalassemia major and 5 with sickle cell/-thalassemia originating from southern Portugal. We found that three mutations, namely the °-39, ° IVS-1 nt 1 and ⁺ IVS-1 nt 110 are prevalent accounting for 53%, 32% and 10% of the -thalassemia chromosomes respectively. In general each mutation was associated with a specific chromosomal haplotype; the ° mutation, however, was linked to three different haplotypes. These results indicate that three oligo-probes complementary to the most common mutations allow prenatal diagnosis by oligonucleotide analysis in 96% of the couples at risk of having offspring with thalassemia major in southern Portugal.     

Synthesis of disaccharide derivatives employing β-N-acetyl- d-hexosaminidase, β-d-galactosidase and β-d-glucuronidase

-N-Acetyl-d-hexosaminidase from Aspergillus oryzae catalysed the stereo- and regiospecific formation of the 6-O-benzylated disaccharide derivatives GalNAc1-3(6- OBn)Gal-SEt and GlcNAc1-3(6-OBn)Gal-SEt, which were obtained in transglycosylation reactions employing ethyl 6- O-benzyl-1-thio--d-galactopyranoside as acceptor. Preparative amounts of the chitobiose derivative GlcNAc1- 3GlcNAc-OPhNO2-p was prepared as well. - N-Acetyl-d-hexosaminidase from bovine testes catalysed the specific synthesis of GlcNAc1-3(6-OBn)GlcNH2-SEt and GalNAc1-3(6-OBn)GlcNH2-SEt, employing ethyl 2-amino-6-O-benzyl-2-deoxy-1-thio--d-glucopyranoside as acceptor. -d-Glucuronidase from E. coli was found to catalyse the formation of GlcA1-3(6-OBn)GlcNH2- SEt employing the same acceptor.     

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     

Bacterial regeneration of ammonium and phosphate as affected by the carbon:nitrogen:phosphorus ratio of organic substrates

The effect of carbonnitrogenphosphorus (CNP) ratio of organic substrates on the regeneration of ammonium and phosphate was investigated by growing natural assemblages of freshwater bacteria in mineral media supplemented with the simple organic C, N, and P sources (glucose, asparagine, and sodium glycerophosphate, respectively) to give 25 different substrate CNP ratios. Both ammonium and phosphate were regenerated when CN and NP atomic ratios of organic substrates were 101 and 161, respectively. Only ammonium was regenerated when CN and NP ratios were 101 and 10–201, respectively. On the other hand, neither ammonium nor phosphate was regenerated when CN and NP ratios were 151 and 51, respectively. In no case was phosphate alone regenerated. As bacteria were able to alter widely the CNP ratio of their biomass, the growth yield of bacteria appeared primarily dependent on the substrate carbon concentration, irrespective of a wide variation in the substrate CNP ratio.     

Diel Movements of Bat Rays, Myliobatis californica, in Tomales Bay, California: Evidence for Behavioral Thermoregulation?

We used ultrasonic telemetry to examine movement patterns of 11 bat rays, Myliobatis californica, in Tomales Bay, California. Tomales Bay is long (20km) and narrow (1.4km), and is hydrographically separated into outer and inner bay regions. The outer bay (the outermost 8km) is characterized by oceanic conditions while the shallow inner bay (the innermost 12km) features wide seasonal temperature shifts. Five rays were tracked monthly from October 1990 to November 1991 and six rays (four of which carried temperature-sensing transmitters) were tracked daily from 30 June to 16 July 1992. Mean bat ray movement rate was 8.84mmin^–1 (range 4.49 to 13.40mmin^–1) and was not significantly affected by size (p=0.592), tidal stage (p=0.610), or time of day (p=0.327). Movement direction was unrelated to tidal stage (p=0.472) but showed a highly significant diel pattern (p<0.001). From 2:50–14:50h, rays moved toward the warmer and shallower inner bay, while from 14:50–2:50h they moved toward the cooler and deeper outer bay. These telemetry data, along with known bat ray foraging patterns and respiratory temperature-sensitivity, argue for behavioral thermoregulation as the primary influence on this movement pattern.     

Partial mispairing and crossing-over between β0 and δ genes as the origin of the δ β0 thalassemia gene

Summary Two double heterozygous ⁰/⁰ thalassemic sibs of Mexican descent were studied. The father had a ⁰/⁰ genotype, while the mother, one sib and several maternal relatives were ⁰/⁰ heterozygotes. Parental consanguinity and an apparently low frequency of thalassemia among Mexicans suggested a possible common origin of both ⁰ and ⁰ genes. A hypothesis to explain such a possibility is proposed on the basis of a partial mispairing between ⁰ and genes followed by a crossing-over which would results in a ⁰ recombinant gene. This hypothesis could also be extended to explain the 22 gluala, 22 alaglu and 116 arghis Hb variants as recombinants from double crossing-over between and mispaired genes for which the name interstitial-Lepore is proposed.     

Die Feinstruktur der Zirbeldrüse normaler,trächtiger und experimentell beeinflußter Meerschweinchen

Zusammenfassung In der Meerschweinchenzirbeldrüse lassen sich elektronenmikroskopisch helle und dunkle Pinealzellen sowie einzelne Gliazellen nachweisen. In den bei weitem überwiegenden hellen Pinealzellen zeichnet sich ein Teil der vesicle-crowned rodlets (VCR) durch lokale Auftreibungen aus. Von VCR deutlich abzugrenzen sind die vesicle-crowned balls (VCB). Erstmalig beschrieben wird das Vorkommen von sog. Zylindern, die als Vorstufen von VCB aufgefaßt werden. In den relativ seltenen dunklen Pinealzellen, die sich durch chromatinreiche Kerne und elektronendichtes Zytoplasma auszeichnen, sind Vesikel, VCR, VCB und Zylinder seltener als in hellen Pinealzellen. Die reichlich vorhandenen marklosen Nervenfasern finden sich vor allem in perivasculären Räumen, seltener im Parenchym. Synapsen zwischen Nerven und Pinealzellen wurden nicht beobachtet. In den Zirbeldrüsen trächtiger Meerschweinchen zeichnen sich in der 2. Hälfte der Tragzeit die hellen Pinealzellen durch stärkere Lappung der Kerne, gehäuftes Auftreten von laktiven Zonen, Vermehrung von Mitochondrien, glattem ER, agranulären Vesikeln, VCR, VCB und Zylindern aus. Die dunklen Pinealzellen nehmen während der Tragzeit an Zahl zu. Post partum bilden sich diese Veränderungen innerhalb einer Woche zurück. Längerer Aufenthalt der Tiere in Dunkelheit führt zu einer Aktivierung der hellen Pinealzellen mit auffallender Vermehrung der VCR und zu einer Zunahme der dunklen Zellen. Unter Dauerbelichtung kommt es in den hellen Zellen zu einer Abnahme fast aller Zellorganellen und zu einer starken Vermehrung der VCR, die nach 70 Tagen auch Formveränderungen aufweisen. Nach Reserpinbehandlung beobachtet man eine Verminderung und degenerative Veränderungen der VCR. Es wird diskutiert, daß die VCR als prae- bzw. postsynaptische Strukturen der Erregungsübertragung von Nerven zu Pinealzellen bzw. von Pinealzellen untereinander dienen könnten.

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The fine structure of the pineal gland of normal, pregnant and experimentally affected guinea-pigs

Summary By means of electron microscopy light and dark pinealocytes can be distinguished in the guinea-pig pineal gland. Glial cells are rare. In the light pinealocyte. the most frequent cell type, some vesicle-crowned rodlets (VCR) show circumscribed thickenings. From these structures vesicle-crowned balls (VCB) have to be clearly distinguished. Furthermore cylinders occur, which, it is suggested, are precursors of VCB. Dark pinealocytes characterized by chromatin-rich nuclei and electron-dense cytoplasm are rare and contain fewer vesicles, VCR, VCB and cylinders than light pinealocytes. Numerous non-myelinated nerve fibres are situated within perivascular spaces, a few also in the parenchyma. Synapses between nerve fibres and pinealocytes were not observed. In the pineal gland of pregnant guinea-pigs the following changes can be observed in the second half of gestation. The light cells show many nuclear indentations and an increase of active zones, mitochondria, smooth ER, agranular vesicles, VCR, VCB, and cylinders respectively. The dark cells increase in number. After birth these changes reverse to normal within one week. Constant darkness leads to an activation of the light cells accompanied by an increase of the VCR and to an increase in number of the dark cells. Under constant illumination the light cells show a decrease of their organelles and a strong increase of the VCR. After 70 days the VCR also show a change in shape. Following reserpine treatment the VCR decrease in number and show signs of degeneration. It is discussed that the VCR function as pre- or postsynaptic structures and that they are involved either in transmitting impulses from nerve fibres to pinealocytes or from one pinealocyte to the other.

Untersuchung unter Leitung von Univ.-Doz. Dr. L. Vollrath.     

γδ T-cell receptor repertoire in human peripheral blood and thymus

T-cell clones expressing the T-cell receptor (Tcr) were generated from peripheral blood lymphocytes (PBLs) and from a thymus sample. In the panel of ten thymus-derived clones, four Tcr phenotypes [as defined by the reaction of monoclonal antibodies (mAbs) directed against known V and V regions] were identified. All the clones lacked expression of the V3 V region, while seven clones were V1+ . V1 was found in combination with V9 or with undefined VVregions. In addition, two other Tcr phenotypes were identified on these clones: V9⁺ V1^– V3^– and V9^– V1^– V3^– One of the clones expressed CD4 and another was CD8positive. The remaining clones were CD4^– CD8^–. In the panel of 76 PBL-derived, Tcr-bearing clones, five Tcr phenotypes could be identified. In contrast to the thymus-derived clones, 30% of the clones were V3⁺ whereas V1 was expressed by a minority of the clones only. One clone was CD4-positive and approximately 30% of the clones were CD8-positive. Four of the five mAb-defined Tcr phenotypes could be identified on both thymus and PBL-derived T-cell clones. However, biochemical analysis of the Tcrs demonstrates differences in the usage of Ct- and C2-encoded y chains by T cells derived from the thymus and PBLs. The results therefore indicate that, at the clonal level, similarities and differences exist between the Tcr repertoires expressed in the thymus and by PBLs. Furthermore, they indicate that combinatorial Tcr heterogeneity is larger than has so far been described. The receptor diversity, combined with the potential of Tcr+ cells to express CD4 or CD8, indicates that these cells are a heterogeneous population that might mediate a number of immune functions.     

Movements and diurnal behaviour patterns in a Baltic grey seal (Halichoerus grypus)

A sub-adult grey seal was caught and tagged with a satellite relay data logger at Tihällan (61°2800N, 17°2540E), Sweden, on 21 August 1992. We tracked it for 115 days during which time we recorded 841 locations, data on 3556 dives and 80 haulout periods. It travelled 730 km in the first 12 days to the southern Archipelago Sea. It stayed most of the remaining time within 25 km of a haulout site, with a major exception of an 8-day trip of 520 km. Dive shape and swimming activity were used to distinguish dive types. Square-shaped foraging dives were more common over the midday period. Haulout periods were more common during the night.     

Population cytogenetics of the genus Caledia (Orthoptera: Acridinae)

The acridine grasshopper, Caledia captiva exists as two chromosomal races in south-east Queensland. One of these, the Moreton race inhabits the coastal region to the east of the Great Dividing Range. All chromosomes of the complement (2n=11II+XO/XX) have been involved in centromeric rearrangement, which transforms the acro- and telocentric chromosomes into submeta- and metacentric elements. The second, or Torresian race is widely distributed through southern Papua, Arnhem Land, Cape York Peninsula and down the east coast of Australia as far south as Brisbane. This race, which is characterised by a completely acro- and telocentric chromosome complement, approaches the Moreton race in south-east Queensland where the two races are separated by less than 1 km, along a front of at least 150 km. Evidence is presented to show that chromosome introgression is occurring across the contact zone and this takes place in one direction only, namely the Torresian chromosomes are infiltrating into the Moreton race but not reciprocally. Furthermore, the introgression of chromosomes across the zone is limited to certain members of the Torresian complement and even then these successful chromosomes show highly variable degrees of penetrance into the Moreton race. It is proposed that a tension zone exists between these two races which is maintained by the interaction of (a) ecological tolerance differences on either side of the zone and (b) by partial competitive exclusion due to the interracial differences in phenology. This case of parapatric association with limited hybridisation is unique in its clarity due to the marked differences in the appearance of the chromosome complements of these races which permits direct assessment of the behaviour of most members of the genome in hybrids and their derivatives.     

Use of15N/14N rations to evaluate the food source of the mysid,Neomysis intermedia Czerniawsky,in a eutrophic lake in Japan

The stable isotope ratios of nitrogen were measured in the mysid,Neomysis intermedia, together with various biogenic materials in a eutrophic lake, Lake Kasumigaura, in Japan throughout a year of 1984/85. The mysid, particulate organic matter (POM, mostly phytoplankton), and zooplankton showed a clear seasonal change in ¹⁵N with high values in spring and fall, but the surface bottom mud did not. A year to year variation as well as seasonal change in ¹⁵N was found in the mysid. The annual averages of ¹⁵N of each material collected in 1984/85 are as follows: surface bottom mud, 6.3 (range: 5.7–6.9); POM, 7.9 (5.8–11.8); large sized mysid, 11.6 (7.7–14.3); zooplankton, 12.5 (10.0–16.4); prawn, 13.2 (9.9–15.4); goby, 15.1 (13.8–16.7). The degree of¹⁵N enrichment by the mysid was determined as 3.2 by the laboratory rearing experiments. The apparent parallel relationship between the POM and the mysid in the temporal patterns of ¹⁵N with about 3 difference suggests the POM (mostly phytoplankton) as a possible food source ofN. intermedia in this lake through the year.     

Improved in situ β-galactosidase staining for histological analysis of transgenic mice

The present study describes a novel method for the histochemical demonstration of -galactosidase activity on tissue sections. We have replaced 5-bromo-4-chloro-3-indolyl--D-galactoside (X-Gal) with 5-bromoindolyl--o-galactopyranoside (Bluo-Gal) as a chromogenic substrate for the bacterial -galactosidase (lacZ). After -galactosidic cleavage, Bluo-Gal precipitates in form of fine birefringent crystals, whereas X-gal gives rise to an amorphous precipitate. Upon microscopic examination under polarized light, the crystals emit a strong signal consisting of yellow reflected light. This property of Bluo-Gal results in greatly enhanced sensitivity of the staining method for -galactosidase and allows for optimal morphological resolution. To exemplify the applications of this technique, the expression is demonstrated in transgenic mice of -galactosidase driven by a fragment of the human tissue-type plasminogen activator promoter.