Linear differentiation of cereal chromosomes

Summary The BSG test was used in a comparative study of the linear chromosome differentiation and the idiograms of T. Macha ssp. tubalicum v. letschchumicum Dek. et Men., T. georgicum Dek., T. timopheevi. Zhuk., T. carthlicum Nevski, T. dicoccum Schrank, v. rufum, T. durum Desf. v. Arnautka were compiled.The karyotype of each polyploid wheat species consists of two groups of chromosomes. The first is formed by ten pairs of constant chromosomes occurring almost in all species and the second by all the rest of the variable chromosomes that are either fully specific for the species in question or occur only in a few species. T. timopheevi largely differs from other species of polyploid wheats in the high level and specific localization of structural heterochromatin on chromosomes. The rols of introgression in wheat evolution and the necessity of establishing a General Cytological Nomenclature of Cereal Chromosomes are discussed.     

Characterization of Aeromonas salmonicida variants with altered cell surfaces and their use in studying surface protein assembly

Aeromonas salmonicida variants were characterized for alterations in their cell surface structure and used to examine reconstitution of the surface protein layer (A-layer). Variants lacking outer membrane O-polysaccharide were devoid of A-layer and excreted stainable floret-like material of the surface protein (A-protein). One variant, showing partial loss of O-polysaccharide, was associated with a disrupted A-layer and excretion of some A-protein. Variants lacking A-protein but possessing O-polysaccharide rapidly absorbed and concentrated sufficient excreted A-protein at the cell surface to coat the cells with a single confluent layer. Although differences in electrophoretic mobilities of A-proteins and O-polysaccharides from typical and atypical strains were evident, the different A-proteins and A-protein-deficient variants were interchangeable for reconstitution of a surface protein layer. No association of A-protein with cell surfaces of unrelated gram-negative bacteria was observed.Abbreviations A-layer additional surface protein layer - A-protein surface protein - Ast Aeromonas salmonicida typical - Asa Aeromonas salmonicida atypical - A^- phenotypically A-protein-negative variant - O^- phenotypically O-polysaccharide-negative variant - O^wk phenotypically O-polysaccharide weak variant - BHI brain heart infusion - SDS-PAGE sodium dodecylsulfate-polyacrylamide gel electrophoresis - TEM transmission electron microscopy     

Whole Leaf Thermoluminescence Emission in Pisum Sativum L.: Influence of Leaflet Age

The thermoluminescence signals from leaflets of the same pea plant varied gradually according to their developmental stage. The AG emission, due to a back flow of electrons towards photosystem 2 (PS2) along a cyclic/chlororespiratory pathway, was stronger in mature leaves than in the growing ones. These age-related variations could be explained by a higher capacity of cyclic electron flow in mature leaves.     

The effect of paclobutrazol on in vitro rooting,transplant establishment and growth of fruit plants

The effect of paclobutrazol on in vitro rooting and growth of sour cherry (Prunus cerasus) rootstock CAB 11E clone, of S 749 × S 1490 (Prunus persica × Prunus kansuensis) hybrid rootstock, and of pear (Pyrus communis), cv. Abbé Fetel is reported.PP333 increased rooting of S 749 × S 1490 and of Abbé Fetel, particularly at a concentration of 0.5 mg/l (a.i.); moreover, it induced a rooting percentage as high as auxin in the former and hastened rooting of the latter. By contrast, paclobutrazol did not affect root production of 11 E.PP333-treated plants had shorter and thicker roots than controls but similar survival rates during acclimatization. Otherwise they grew less than controls during the first part of the acclimatization phase.Abbreviations used in text and tables BA = 6-benzyladenine - IBA = indole-3-butyric acid - PP333 = paclobutrazol = (2RS,3RS)-1-(-4-chlorophenyl)-4,4-dimethyl-2-(1H-1,2,4-triazol-1-yl)pentan-3-ol Part of the results referring to S 749 × S 1490 (P. persica × P. kansuensis) rootstock were presented at the meeting on Controllo della fruttificazione delle piante da frutto, Bologna, Italy, June 1986, and were published in the Riv. Ortoflorofrutt. It. 70 (6)(1986). This research was funded in part by the Italian Ministry of Education (M.P.I. 60%).     

Direct arteriovenous connections and the intermediate circulation in dog spleen,studied by scanning electron microscopy of microcorrosion casts

Summary The exact nature of the circulatory pathways in dog spleen, particularly with reference to the intermediate circulation and the possible existence of direct arteriovenous connections, has been studied by scanning electron microscopy (SEM) of microcorrosion casts. A new casting procedure was developed in which minimal amounts of material were injected into contracted spleens, thus filling preferentially the faster channels for flow. Extensive filling of the red pulp was thereby avoided, leaving an open view of blood vessels and their connections. The depth of focus of the SEM, incomparably greater than those of transmission electron or light microscopes, enabled vascular pathways to be traced over considerable distances.Using this approach, we have obtained clear evidence for abundant connections between arterial capillaries and venous sinuses (i.e., closed circulation). Typically, the terminal arteriole bifurcates repeatedly, in quick succession, giving rise to as many as twelve short capillaries, each leading directly to at least one sinus. However, an open circulation also exists, inasmuch as the majority of all capillaries end in the marginal zone around lymphatic nodules. In the dilated spleen, direct connections to sinuses are rarely visible but endings in the red pulp are found, in addition to those going to the marginal zone.     

Fluorescence-microscopical demonstration of a population of gastro-intestinal nerve fibres with a selective affinity for Quinacrine

Summary A population of nerve fibres in the gastro-intestinal tract of mice showing a high affinity for quinacrine was revealed by fluorescence microscopy. Similar results were obtained in rats and guinea pigs. Whole-mounts of sheets of the smooth muscle layer following incubation in 10^-6-10^-7 M quinacrine for 15–60 min revealed fine fluorescent varicose nerve fibers in the myenteric plexus of Auerbach both around nerve cell bodies and in the interconnecting strands. Many fibers were also present between the strands of the plexus, especially running parallel to the circular muscle layer. Such fibers were not seen in similarly quinacrine-incubated irides. A proportion of the cell bodies in Auerbach's plexus also showed quinacrine accumulation. These cells were apparently smaller neurons, sometimes with fluorescent processes. Intraperitoneal injections of quinacrine failed to demonstrate nerve fibers, but some cell bodies in Auerbach's plexus were positive. Subsequent paraformaldehyde treatment for monoamine visualization showed persistent adrenergic nerve terminals in the intestine and iris. These nerves seemed to be fewer and had a more yellow fluorescence than normally. The identity of the quinacrine-positive fibers is discussed with respect to recent suggestions that purinergic, substance P, enkephalin, and somatosin-containing nerves, in addition to adrenergic and cholinergic nerves, are present in the gut wall.Supported by the Swedish Medical Research Council (04X-03185). Magnus Bergvalls Stiftelse and Karolinska Institutets Fonder. For generous gifts of Mepacrine we thank Winthrop, Skärholmen, Stockholm, Sweden. The skilful technical assistance of Miss Gerd Boetius and Miss Maud Eriksson is gratefully acknowledged     

Expression of surface hydrophobicity encoded by R-plasmids in Escherichia coli laboratory strains

The inclusion of drug-resistance plasmids (R-plasmids) in Escherichia coli strains has been shown to determine the formation of specific surface structures which could modify bacterial surface characteristics relevant for pathogenic processes.Thirtyone R-plasmids (from different incompatibility groups) have been transferred to three E. coli laboratory strains, and surface hydrophobicity modifications have been measured by three methods: salting-out, adsorption to hexadecane and adsorption to xylene.The results obtained show that the presence of R-plasmids produced variations which are dependent on the receptor strains and measuring method employed. Also, it has been found that the plasmids behave differently depending on the strain in which they are included.The results obtained by the salting-out method are not correlative with those obtained by adsorption to hydrocarbons, probably due to the implication of different hydrophobic molecules in the interaction with salt or hydrocarbons.Concluding, the choice of receptor strain and measuring method are of great importance for the investigation of surface hydrophobicity (and probably other characteristics) encoded by R-plasmids.Abbreviations TSB Trypticase soya broth - TSA trypticase soya agar     

The feeding ecology of a carnivorous plant (Pinguicula nevadense): prey analysis and capture constraints

Summary The taxonomic composition and size of arthropods captured by Pinguicula nevadense, an endemic carnivorous plant of the high-mountain zone of the Sierra Nevada (southern Spain), are analysed. The actual prey of P. nevadense and the available arthropods trapped by mimic-traps are compared, in order to identify the capture constraints of the plant. The results show that P. nevadense captures various arthropod taxa. Winged insects, especially Nematocera, make up the main component of the diet. The range of prey sizes in all P. nevadense populations studied is similar. The taxonomic composition of arthropods trapped by the mimic-traps is similar to that of the actual prey of P. nevadense. However, the plant captures prey only below a specific size threshold. These size constraints appear to be the principal factor determining the actual prey of this carnivorous plant.     

Expression and inheritance of kanamycin resistance in a large number of transgenic petunias generated by Agrobacterium-mediated transformation

One hundred and four kanamycin-resistant Petunia Mitchell plants were regenerated from leaf discs cocultivated with Agrobacterium tumefaciens strain LBA4404 containing a binary vector pCGN200. Selection for kanamycin resistance was applied during plant regeneration at the initiation of both shoots and roots. The regenerated plants were analysed for expression and inheritance of their kanamycin resistance phenotype. Approximately half of the plants showed normal Mendelian inheritance for one or two kanamycin resistance genes. In one case, the two copies were inserted at closely linked sites on homologous chromosomes, and gave <0.05% kanamycin-sensitive progeny on backcrosses. Six plants had inheritance patterns suggesting that the kanamycin gene had inserted into an essential region of DNA. Forty-five plants showed lower than expected transmission of kanamycin resistance, which was associated with low expression of the resistance phenotype in most cases. Ten plants produced segregation ratios that are not readily interpreted by Mendelian inheritance.     

Day-night differences in the number of pineal “synaptic” ribbons in two diurnal rodents,the chipmunk (Tamias striatus) and the ground squirrel (Spermophilus richardsonii)

Summary Daytime numbers of pineal synaptic ribbons higher than reported in the pineal gland of any other mammalian species were observed in two diurnal rodents, the eastern chipmunk and Richardson's ground squirrel. The number of synaptic ribbons was lower during the daytime and higher at night in both of these species.     

The relation between the levels of extractable and diffusible IAA in almond fruits and their “June drop”

The relationship between the June drop of almond fruits(cv. Truoito) and the levels of extractable and diffusible IAA of the fruit wasstudied. June drop started almost simultaneously with thedecreasein the concentration of extractable free and ester IAA from seeds and theamountof diffusible free IAA from persisting fruits. The drop lasted for a period ofabout 17 days, during which time the auxin decreased constantly. In a secondexperiment, the relationship between fruit size, fruit drop and level of auxinwas examined. The fruits were classified according to size into threecategories, large, intermediate and small. Throughout the experiment thepercentage of small fruits that abscised (70%) was five times higher than thatof the other categories of fruits. The small persisting fruits had lower levelsof extractable free and diffusible free IAA than fruits of intermediate andlarge size. When the process of abscission advanced and the diffusion of theauxin had been interrupted, an increase in the concentration of extractablefreeand peptidic IAA in the seeds and pericarps of the abscising fruits wasobservedcompared with the persisting fruits.     

Polymerization of the Actin Component of the Cytoskeleton and Formation of the Geometry of a Cultured Nerve Cell (a Model Study)

Using mathematical modeling, we studied the biophysical aspects of the growth of the cell membrane and the growth of the actin network of the cytoskeleton of a neuron cultured on the rigid sublayer and the correlation between these processes. To describe the dynamics of the growth of the cytoskeleton limited by the cell membrane, we used the model of the thermal ratchet. Using the approaches of theoretical biophysics, we obtained a simple biophysical criterion that governs the selection of an alternative scenario of the formation of the cell, either growth of a single neurite or growth of a number of neurites. This criterion depends on the value of the adhesion between the cell and the substrate, the dimension of the actin monomer, and the thermal energy determining the frequency of thermal fluctuations of the cell membrane.     

Highly asymmetric intergeneric nuclear hybrids between Nicotiana and Petunia: evidence for recombinogenic and translocation events in somatic hybrid plants after “gamma”-fusion

Summary Extremely asymmetric nuclear hybrids have been obtained via protoplast fusion in an intergeneric combination. Irradiated (cobalt⁶⁰,100 krad) kanamycinresistant Petunia hybrida mesophyll protoplasts were chemically fused with wild-type mesophyll protoplasts of Nicotiana plumbaginifolia. Eighty-six hybrid colonies were selected on kanamycin-containing medium, and twenty-four of these could be induced to regenerate numerous shoots. Cytological analysis of the regenerants showed the presence of a few chromosome fragments in some lines, and even a metacentric chromosome in yet another line. Besides additional chromosome fragments some lines only possessed typical Nicotiana chromosomes, and this at the diploid (2n = 2X = 20) as well as the tetraploid (2n = 2X = 40) level. Biochemical analysis showed that all regenerants had neomycin phosphotransferase activity (NPTII), which suggests that intergenomic recombination and or translocation events took place at least in those lines where no additional chromosome fragments could be detected. The presence of the NPTII gene was shown by Southern hybridization. All regenerants tested were fertile, and the segregation ratios for the kanamycin gene (for self and backcross pollinations to the recipient partner) for some of the regenerants correspond with Mendelian rules for a monogenic dominant marker. Most of the regenerants showed abnormal segregation ratios; in this case, no correlation could be made between segregation ratio and chromosome composition.Our results demonstrate the existence of intergenomic recombination and translocations evens in nuclear somatic hybrid plants obtained via gamma-fusion.     

Cytoarchitectonic pattern of the hypothalamus in the cobra,Naja naja

Summary The distribution and cytoarchitectonic pattern of the magno- and parvocellular hypothalamic nuclei of the cobra, Naja naja, are described at the light-microscopic level. With respect to their tinctorial affinity to paraldehyde fuchsin (AF) as a representative of the Gomori-type of stains, the magnocellular neurons belong to the AF-positive and the parvocellular neurons to the AF-negative elements. In addition to the supraoptic and paraventricular nuclei proper, two accessory aggregations of magnocellular neurons, the nucleus retrochiasmaticus and nucleus circularis, can be identified. Although in a peculiar location, they may be regarded as subunits of the supraopticoparaventricular neurosecretory complex. As many as 22 AF-negative nuclear areas are identified in the hypothalamus of the cobra. The nucleus periventricularis hypothalami of earlier authors is subdivided into several circumscribed neuronal complexes. The nucleus arcuatus, nucleus hypothalamicus lateralis and nucleus lateralis recessus infundibuli are well developed. An attempt is made to interpret the significance of these nuclei on a comparative and phylogenetic basis.On leave from the Department of Zoology, Nagpur University, Nagpur, India     

Energy Metabolism of Synaptosomal Subpopulations from Different Neuronal Systems of Rat Hippocampus: Effect of L-Acetylcarnitine Administration In Vivo

The maximum rate (V_max) of some enzyme activities related to glycolysis, Krebs' cycle, acetylcholine catabolism and amino acid metabolism were evaluated in different types of synaptosomes obtained from rat hippocampus. The enzyme characterization was performed on two synaptosomal populations defined as large and small synaptosomes, supposed to originate mainly from the granule cell glutamatergic mossy fiber endings and small cholinergic nerve endings mainly arising from septohippocampal fiber synapses, involved with cognitive processes. Thus, this is an unique model of pharmacological significance to study the selective action of drugs on energy metabolism of hippocampus and the sub-chronic i.p. treatement with L-acetylcarnitine at two different dose levels (30 and 60 mg · kg^–1, 5 day a week, for 4 weeks) was performed. In control animals, the results indicate that these two hippocampal synaptosomal populations differ for the potential catalytic activities of enzymes of the main metabolic pathways related to energy metabolism. This energetic micro-heterogeneity may cause their different behaviour during both physiopathological events and pharmacological treatment, because of different sensitivity of neurons. Therefore, the micro-heterogeneity of brain synaptosomes must be considered when the effect of a pharmacological treatment is to be evaluated. In fact, the in vivo administration of L-acetylcarnitine affects some specific enzyme activities, suggesting a specific molecular trigger mode of action on citrate synthase (Krebs' cycle) and glutamate-pyruvate-transaminase (glutamate metabolism), but mainly of small synaptosomal populations, suggesting a specific synaptic trigger site of action. These observations on various types of hippocampal synaptosomes confirm their different metabolic machinery and their different sensitivity to pharmacological treatment.     

Rotala cookii: A new species ofLythraceae from India showingHippuris syndrome

A new aquatic species ofRotala (Rotala cookii) is described from Kerala, India. Growing in the flooded lowlands, along the coastal belt, the plant is a Hippuris mimic.     

Zur Feinstruktur der Spezialzellen von normalernährten und hungernden Aeolidiern (Gastr. Nudibranchia)

Zusammenfassung Die Spezialzellen im Bindegewebe der Kolben von Eubranchus farrani und Trinchesia granosa (Aeolidoidea) bilden Gruppen, die stets von einer Basallamina umschlossen werden. Die Zellen werden nicht durch desmosomale Bildungen untereinander verbunden. In den oft geweiteten Interzellularlakunen findet sich feinstflockiges Material. Spezialzellen normal ernährter Schnecken besitzen ein außerordentlich reiches, geordnetes, rauhes endoplasmatisches Retikulum und einen großen Kern mit großem Nucleolus. Golgi- und Vakuolenapparat der Zellen bleiben klein. Mit zunehmender Dauer des Fastens wird das rauhe ER durch ungeordnetes, glattes endoplasmatisches Retikulum ersetzt, wächst der Golgiapparat und nimmt die Zahl der Autolysosomen zu. Die feinstrukturellen Unterschiede zwischen Spezialzellen, Blasenzellen und Nervenzellen werden beschrieben, die Funktion der Spezialzellen abschließend diskutiert.

---

An electron-microscope study of cellules spéciales in normally nourished and starved aeolids (Gastr. nudibranchia)

Summary Cellules spéciales of Aelidoidea have been investigated in the cerata of Eubranchus farrani and Trinchesia granosa. All groups of cellules spéciales are limited by a basal lamina. Opposing membranes are not connected by specialized structures as desmosomes etc. The intercellular cleft often is widened and contains a fine floccular substance. In normally nourished animals the cellules spéciales show a rich, highly organized, rough surfaced reticulum, while there are only a few vacuoles and a small Golgi Complex. In starved animals mainly smooth reticulum is found, but the Golgi Apparatus has enlarged and autolysosomes are abundant. The fine structural differences of cellules spéciales, globular cells and nerve cells are described, the function of the cellules spéciales is discussed.

Mit dankenswerter Unterstützung durch den Schweizerischen Nationalfond zur Förderung der Wissenschaften und die Deutsche Forschungsgemeinschaft. Ich danke ferner für die guten Arbeitsmöglichkeiten in der Zoologischen Abteilung der Stazione Zoologica Napoli und Frau A. Merkelbach (Tübingen) für technische Assistenz.     

Histochemical and chemical studies on pre- and postnatal development of the different systems of “short” and “long” adrenergic neurons in peripheral organs of the rat

Summary The adrenergic innervation in the submaxillary gland, heart, kidney, small intestine, and accessory male genital organs and the development of the adrenal chromaffin cells and the sympathetic ganglia were studied in the rat from 15 days post coitum to 16 days post partum using the fluorescence histochemical method of Falck and Hillarp. The postnatal development of the noradrenaline concentrations in the heart and vas deferens was followed by fluorometric determinations.At about 15 days post coitum, the anlagen of the sympathetic chains were well visible in the form of two dorsal segmented columns of small branching sympathicoblasts exhibiting an intense catecholamine fluorescence. In the midline, ventrally to these two anlagen, another column of sympathicoblasts developed; this seemed to give rise to the prevertebral ganglia and to the short adrenergic neurons supplying the internal genital organs. At the level of the adrenal anlagen, small intensely fluorescent chromaffin cells were collected in two bilateral groups which became enclosed by adreno-cortical cells. This enclosure was, however, not complete even at two weeks post partum.Bundles of growing sympathetic nerves were visible in the periphery of the various organs studied at 19–21 days post coitum. A terminal innervation of the organs suggestive of a functional transmitter mechanism did not start to establish until at or immediately after birth. The final pattern of innervation was usually reached at about one week post partum, and the following development proceeded largely in the form of a quantitative increase in the number of nerves participating in the innervation apparatus. The adult level of noradrenaline in the heart and vas deferens was reached three to five weeks after birth. The small intestine was an exception in that the final pattern of innervation in the wall was attained immediately after birth.There was no overt difference in the rate of development of the terminal sympathetic innervation in organs supplied by short adrenergic neurons (accessory male genital organs) compared to the innervation of the submaxillary gland, heart and kidney, which receive classical long adrenergic neurons.The work was supported by a grant from the Association for the Aid of Crippled Children, New York, and was carried out within a research organization sponsored by the Swedish Medical Research Council (grants No. B71-14X-56-07A and B71-14X-712-06A).