Cytological evidence on the ability of the nucleolus organizing regions to assemble pre-existing nucleolar material

The treatment of Vicia faba root tips with 5-azacytidine caused unequal allotment of the chromosomes; after one cell cycle, a pair of daughter nuclei was produced, one of which carried the nucleolus organizing regions (NORs) and the other of which lacked them. The pre-existing nucleolar material brought into the NOR-carrying daughter nucleus by the chromosomes disappeared concurrently with the appearance of the new nucleoli, whereas in another daughter nucleus without the NOR a number of small nucleolus-like bodies became visible at random positions. These findings suggest that in addition to ribosomal RNA synthesis the NOR has another role in cells; to stimulate the pre-existing nucleolar material to assemble at the NOR itself.     

Cytological evidence on the ability of the nucleolus organizing regions to assemble pre-existing nucleolar material

Summary The treatment ofVicia faba root tips with 5-azacytidine caused unequal allotment of the chromosomes; after one cell cycle, a pair of daughter nuclei was produced, one of which carried the nucleolus organizing regions (NORs) and the other of which lacked them. The pre-existing nucleolar material brought into the NOR-carrying daughter nucleus by the chromosomes disappeared concurrently with the appearance of the new nucleoli, whereas in another daughter nucleus without the NOR a number of small nucleolus-like bodies became visible at random positions. These findings suggest that in addition to ribosomal RNA synthesis the NOR has another role in cells; to stimulate the pre-existing nucleolar material to assemble at the NOR itself.     

Über das Hauptproblem bei konvexen Rotationskörpern

Summary It is shown that over the distance 0X8/² in the diagram, there is a region which is free from picture points («Bildpunkten») of the convex rotation bodies. This assertion is based on two different groupings of the convex rotation bodies into troops, namely at constant lengthl and constant radius of the equatorr, and at constantl and constant length of the resulting meridial curveL. From this, new relations like between the measurements of the convex rotation bodies follow.     

Neuromodulation by serotonin and octopamine in the honeybee: behaviour,neuroanatomy and electrophysiology

The biogenic amines serotonin (5HT) and octopamine (OA) exist in the bee and can modulate neuronal activity and behaviour. 5HT-like and OA-like immunoreactivities can be found in most neuropils of the brain. Binding sites for the two amines are also present in most brain neuropils. The highest density of binding sites for [³H]serotonin and [³H]octopamine was found in the mushroom bodies. In some brain areas, especially the mushroom bodies, mismatches exist between binding sites and immunoreactivities, suggesting that the two amines also bind to neuropils which are not directly innervated by 5HT-like or OA-like immunoreactive neurons. The action of the two amines on behaviour in the bee is antagonistic. In the antennal pathway, proboscis and antennal responses to olfactory and gustatory stimuli are enhanced by OA and reduced by 5HT. In olfactory conditioning experiments, storage and retrieval of the learned signal can be enhanced by OA and reduced by 5HT. The specificity of these effects depends on the site of amine application in the neuropil. In the visual system the direction specificity of the visual antennal response is enhanced by OA and reduced by 5HT after topical application or injection into the lobula, the third optic ganglion. Correlates for the behavioural modulation can be found in higher-order visual interneurons. While OA application can mimic the stimulation of the bee with sugar water, the behavioural conditions leading to the release of 5HT are not yet known.     

Structural organization and cellular localization of tuftelin-interacting protein 11 (TFIP11)

Tuftelin-interacting protein (TFIP11) was first identified in a yeast two-hybrid screening as a protein interacting with tuftelin. The ubiquitous expression of TFIP11 suggested that it might have other functions in non-dental tissues. TFIP11 contains a G-patch, a protein domain believed to be involved in RNA binding. Using a green fluorescence protein tag, TFIP11 was found to locate in a novel subnuclear structure that we refer to as the TFIP body. An in vivo splicing assay demonstrated that TFIP11 is a novel splicing factor. TFIP11 diffuses from the TFIP body following RNase A treatment, suggesting that the retention of TFIP11 is RNA dependent. RNA polymerase II inhibitor (-amanitin and actinomycin D) treatment causes enlargement in size and decrease in number of TFIP bodies, suggesting that TFIP bodies perform a storage function rather than an active splicing function. The TFIP body may therefore represent a new subnuclear storage compartment for splicing components.Received 8 December 2004; received after revision 27 January 2005; accepted 8 March 2004The nucleotide sequence for the cDNA to mouse TFIP11 (previously known as TIP39 and TIP39kDa) has been submitted to Gen- Bank^TM/ EBI Data Bank with accession numbers AF290474 and NM_018783. The accession number for the human TFIP11 homologueis NM_012143.     

Immobile survival of motoneuron (SMN) protein stored in Cajal bodies can be mobilized by protein interactions

Reduced levels of survival of motoneuron (SMN) protein lead to spinal muscular atrophy, but it is still unknown how SMN protects motoneurons in the spinal cord against degeneration. In the nucleus, SMN is associated with two types of nuclear bodies denoted as gems and Cajal bodies (CBs). The 23 kDa isoform of fibroblast growth factor-2 (FGF-2²³) is a nuclear protein that binds to SMN and destabilizes the SMN-Gemin2 complex. In the present study, we show that FGF-2²³ depletes SMN from CBs without affecting their general structure. FRAP analysis of SMN-EGFP in CBs demonstrated that the majority of SMN in CBs remained mobile and allowed quantification of fast, slow and immobile nuclear SMN populations. The potential for SMN release was confirmed by in vivo photoconversion of SMN-Dendra2, indicating that CBs concentrate immobile SMN that could have a specialized function in CBs. FGF-2²³ accelerated SMN release from CBs, accompanied by a conversion of immobile SMN into a mobile population. Furthermore, FGF-2²³ caused snRNP accumulation in CBs. We propose a model in which Cajal bodies store immobile SMN that can be mobilized by its nuclear interaction partner FGF-2²³, leading to U4 snRNP accumulation in CBs, indicating a role for immobile SMN in tri-snRNP assembly.     

In vitro synthetic activity of the juvenile ovotestis ofHelix aspersa: Influence of the brain and the dorsal bodies

Summary A bioassay was developed inHelix aspersa to study the effect of known endocrine centers on the twomonth-old gonad, using organ culture. The incorporation of¹⁴C leucine and³H fucose in the juvenile gonad almost doubled over control levels, in the presence of the brain and the dorsal bodies.     

α1-Adrenergic stimulation of ketogenesis and fatty acid oxidation is associated with inhibition of lipogenesis in rat hepatocytes

Summary The effect of norepinephrine on fatty acid synthesis (³H₂O incorporation into fatty acids), on fatty acid oxidation to CO₂ and on ketogenesis was studied in isolated hepatocytes of fed rats. After incubation with norepinephrine (50 M), lipogenesis was lower (5.7±1.1 nmoles³H₂O incorporated into fatty acids/mg dry weight/30 min) than in controls (7.5±1.7; n=6, p<0.02). In contrast, (1-¹⁴C) palmitate conversion into total ketone bodies was increased to 10.9±1.8 nmoles/mg/30 min with norepinephrine, vs 8.5±1.6 in controls (p<0.05), and more (1-¹⁴C) palmitate was converted to¹⁴CO₂ with norepinephrine than in controls (1.48±0.10 nmoles/mg/30 min vs 1.06±0.11, p<0.05). The inhibitory effect of norepinephrine on lipogenesis was abolished by addition of the ₁-receptor blocker prazosin, but not by ₂ or -blockers. The results demonstrate that the ketogenic effect of norepinephrine is coupled with an inhibitory effect on lipogenesis which may be explained by diminished activity of acetyl-CoA carboxylase, diminished formation of malonyl-CoA and decreased activity of carnitine palmitoyl transferase I.     

Über die Vermehrung der Polkörperchen während der Segmentation von Ratteneiern bei Vitamin-A-Mangel und -Überdosierung

Summary In the course of histochemical investigations on pre-implanted rat eggs it was found that eggs from animals with vitamin-A-deficiency or -overdosage show an increased number of polar bodies during the first 2 cleavages. Moreover, the polar bodies persist longer than normal.     

Different marrow cell number requirements for the haemopoietic colony formation and the cure of the W/Wv anemia

Summary The lowest cell number in the normal marrow transplant, which allows the cure of W/W^v anemia was found to be between 10⁴ and 10⁵. This exceeds by several times the lowest cell number necessary for the haemopoietic colony formation. Therefore, either the colony forming cell is not the haemopoietic stem cell but rather its progeny, or this cell requires an aid from some other cells to exert its activity.Acknowledgments. We are indebted to Doc. Dr Maksymilian Siekierzynski for his help and advice and to Miss Elzbieta Szewczyk for expert technical assistance.     

Analysis of nuclear apoptotic process in a cell-free system

We report an analysis of the apoptotic process of mouse liver nuclei induced in a cell-free carrot cytosol system by cytochrome c. Typical characteristics of apoptosis were observed, such as chromatin condensation, margination, apoptotic bodies and DNA ladders. Furthermore, transmission and scanning electron microscope analysis of the apoptotic nuclei detected chromatin-free nuclear vesicles before apoptotic bodies appeared at a comparatively late phase. When AC-YVAD-CHO, an inhibitor of caspase 6, was introduced into the system, these vesicles and apoptotic bodies disappeared completely within our study sections. We confirmed the results using whole-mount electron microscopy, and found that although the nuclear lamina was destroyed early, the nuclear matrix largely remained intact during the course of apoptosis. The nuclear matrix played an important role in maintaining the integrity of apoptotic cells and connecting the apoptotic bodies and apoptotic nucleus. Received 29 September 2000; revised 10 December 2000; accepted 13 December 2000     

Thermal conductivity of wax comb and its effect on heat balance in colonial honey bees (Apis mellifera L.)

Summary Wax comb was found to have a thermal conductivity of 0.36×10^–3 cal/cm sec °C. At low air temperatures, honey bees,Apis mellifera L., form clusters inbetween the combs in their nests. The combs provide insulation and the bee behavior actually increases the insulating effectiveness of the combs. When they form a compact living layer over the wax comb, the conductivity can be reduced to 0.065×10^–3 cal/cm see °C. Some aspects of the role of the wax comb in heat balance are examined in this paper.     

Phospholipid and fatty acid composition of lamellar bodies isolated from chicken lungs at different stages of development]

In order to elucidate whether the lamellar body content represents functional surfactant as soon as these bodies appear in lung epithelium during fetal development, lamellar bodies were isolated from lungs of Chicken at various developmental stages. Their content was analyzed and compared to extra-cellular functionnal surfactant. The results show that this content undergoes gradual changes in the phospholipid/protein ratio, as well as in the relative phosphatidylcholine amount. Thus, in the Chicken, nascent lamellar bodies do not represent the final form of extracellular surfactant.     

Kinetics and inotropic action of probenecid in guinea-pig heart in vitro

Summary Probenecid (100–750 g·ml^–1) was found to inhibit cardiac contraction force in untreated and digoxin-treated (100 g·ml^–1) isolated right guinea-pig atrium in vitro by a reversible process, without influencing beating frequency. At low concentrations (1.5–60 g·ml^–1),¹⁴C-probenecid was accumulated into right atrium by an oxygen-dependent process. Correlation between uptake and negative inotropic action of probenecid could not be found.     

Strong mutagenic action of a bipyridylium herbicide in a N2-fixing blue-green alga

Summary The herbicide paraquat (1,1-dimethyl-4,4-bipyridylium ion) has been found to exert a growth inhibitory effect on the N₂-fixing blue-green algaNostoc muscorum in nitrogen-free (N₂) and NO ₃ ^– media, without any apparent inhibitory or stimulatory effect on the heterocyst-forming capacity of the organism. With a dose of paraquat permitting about 20 and 50% survival of this alga a reverse mutation (fromhet ⁺ nif ^– auxotrophy tohet ⁺ nif ⁺ prototrophy), a forward mutation (for L-methionine-DL-sulfoximine [MSO]-resistance), and an auxotrophic mutation (for carbon-auxotrophy through methylamine [MA]-resistance) have been obtained. The toxic and mutagenic effects of this agrochemical have been compared with those of the well known mutagen MNNG (N-methyl-N-nitro-N-nitrosoguanidine) and found to be stronger than those of the latter in each case.The author wishes to thank Mr Girish Nath, Lakshami Chemicals Pvt. Ltd., Phatuha (Patna), India, for providing pure samples of the herbicide for the present investigation. The receipt of financial assistance for this work in the form of a Higher Research Associateship Award to the author from the University Grants Commission, Govt. of India, New Delhi-110002 (Grant No. F/16-51/83), is thankfully acknowledged.     

Effect of 723-1723-1723-1on ethanol withdrawal in mice

Summary ⁹ (10 mg/kg, i.p.) administered to mice immediately after withdrawal from a 3-day exposure to ethanol vapor was found to intensify withdrawal reactions. No effect was seen when ⁹ was administered chronically during the exposure to ethanol.     

Über den Einfluss isotopischer und nichtisotopischer Träger auf die Verteilung von Radiostrontium im Organismus der Ratte

Summary Investigating the influence of isotopic or nonisotopic carriers on the behaviour of Sr⁹⁰ in the rat, calcium was found to be ineffective, whereas magnesium was essentially more effective in reducing the deposition of Sr⁹⁰ in the skeleton as equimolar amounts of stable strontium. According to these results, neither calcium nor magnesium can act as ‘biological’ carrier for radiostrontium.      

Heavy incorporation of3H-prostaglandin F2α in the neoplastic cells as revealed by autoradiographic studies

Summary A marked uptake (9-fold) of the³H-PGF₂ was found specifically over heterochromatin in the nuclei of neoplastic cells. Lower but significant uptakes of³H-PGF₂ were also found in the nuclei of control epidermal cells, which indicate the presence of nuclear receptors in the epidermal neoplastic cells.     

Catecholamines in bovine semen

Summary In seminal plasma 5×10^–6 M noradrenaline was found to induced head-to-head association in bull spermatozoa. The sum of noradrenaline and adrenaline in freshly collected semen was 10 ng/ml (5.2×10^–8M), i.e., about 100 times lower than previously reported.     

Cleavage of des-Arg9-bradykinin by angiotensin I-converting enzyme from pig kidney cortex

Summary Fast and very slow hydrolyses of des-Arg⁹-bradykinin and angiotensin II by angiotensin I-converting enzyme were detected by high performance liquid chromatography. The Michaelis constants of the enzyme, K_m values, for des-Arg⁹-bradykinin and bradykinin were found to be 0.24 mM and 4.4 M, and the maximum velocities, V_max values (mol·min^–1·mg protein^–1) for these compounds to be 3.24 and 0.34, respectively. The enzyme also hydrolyzed Z-Gly-Pro-Gly-Gly-Pro-Ala to a tripeptide that was identified as dansyl-Gly-Pro-Ala by TLC on polyamide. These observations show that the enzyme hydrolyzes the peptides at the bond before the prolyl residue in the penultimate position.Acknowledgments. We thank Dr Kinzo Nagasawa of Kitasato University for encouragement in this work and Dr Ervin G. Erdös, University of Texas, Health Science Center, Dallas, for valuable discussion and suggestions.Abbreviations used: Z, carbobenzoxy; Bz, benzoyl; ACE, angiotensin I-converting enzyme; BK, bradykinin; HPLC, high performance liquid chromatography.