Notes on the Mechanism of ATP Synthesis

The most commonly quoted mechanism of the coupling between the electrochemical proton gradient and the formation of ATP from ADP and P_i assumes that all states of the F₁ portion of the ATP synthase have subunits in tight, loose, and open conformations. Models based on this assumption are inconsistent with some of the available experimental evidence. A mechanism that includes an additional subunit conformation, closed, observed in the rat liver structure overcomes these difficulties.     

A field study of emotions,dominance, and social behavior in a group of baboons (Papio anubis)

This study involved the testing of a new rating instrument designed to measure emotional behavior, and the examination of the correlations between dominance and certain classes of emotional behavior. The sample population was a troop of 7 olive baboons. The rating scale was found to be very effective. Wide individual differences in scores on the 8 dimensions of the scale were detected. Also, there was high interjudge reliability indicating that independent observers can agree on the temperamental characteristics of primates. Mean time being groomed, a duration/frequency ratio, more fully reflects the dominance relationship between two animals than any other single index. Mean time being groomed was found to correlate significantly with the dimensionsprotection, deprivation, rejection anddestruction. More dominant animals showed less sociability and more aggression than the submissive animals, who showed a great deal of both sociability and fearfulness.     

β-Adrenoceptors in the Tree Shrew Brain. II. Time-Dependent Effects of Chronic Psychosocial Stress on [125I]Iodocyanopindolol Binding Sites

1. Stress is known to affect the functioning of the central noradrenergic system in a region-specific manner. The aim of the present investigation was to understand better the consequences of recurrent stressful experiences on central -adrenoceptors.2. Alterations in the central nervous -adrenoceptor system resulting from different periods of psychosocial stress (PSS) were analyzed in male tree shrews (Tupaia belangeri) which were submitted to subordination stress for varying time periods.3. In the first experiment, the whole number of -adrenoceptors was analyzed in the forebrains of subordinate animals and controls by in vitro autoradiography using ¹²⁵I-iodocyanopindolol (¹²⁵ICYP), while nonspecific binding of the radioligand to serotonin receptors was blocked with 100 M 5HT.4. PSS affects -adrenoceptors in a time-dependent manner. A decrease in receptor affinity occurred after just 21 days of PSS in cortical areas and in the hippocampus, indicating stress effects on the conformation of -adrenoceptors. After 30 days of PSS,the numbers of -adrenoceptors were significantly decreased in several cortical regions and in the olfactory area.5. In the second experiment, we investigated the influence of PSS on both ₁- and ₂-adrenoceptors separately. ¹²⁵ICYP binding was quantified in the presence of either ICI188.551 to block ₂-adrenoceptors or in the presence of CGP20712A to block ₁-adrenoceptors.6. After 2, 10, 21,and 28 days of PSS, it become apparent that the two -adrenoceptor subtypes are regulated independently. ₁-Adrenoceptors were transiently down-regulated after 2 days of PSS in the prefrontal cortex and in the olfactory area and were decreased after 28 days of PSS in the parietal cortex and the hippocampus. A transient up-regulation of ₁-adrenoceptors occurred in the pulvinar nucleus after 10 days of PSS. ₂-Adrenoceptors were transiently down-regulated after 2 days of PSS in the prefrontal cortex and up-regulated in the pulvinar nucleus after 28 days of PSS.7. These data demonstrate that chronic psychosocial stress in subordinate tree shrews leads to time-dependent changes in the central nervous -adrenoceptors system.8. The high regional variability in stress-induced -adrenoceptor regulation is supposed to be due to the complex mechanisms of intracellular -adrenoceptor sequestration, which includes down-regulation and/or reinsertion of receptors into the plasma membrane. These mechanisms may be important components of the regulatory apparatus which enables the individual to adapt to situations of recurrent stressful experiences by balancing the central nervous adrenoceptor number.     

Refinement of Harrison's normal table for the morula and blastula of the axolotl

Summary Films of cleaving embryos of the axolotl,Ambystoma mexicanum, taken by the double camera technique, were used in order to arrive at a more detailed staging based on quantitative criteria. Drawings were made of the animal hemispheres just prior to the start of each cleavage cycle from the 6th to the 15th cleavage. The number of cells intersected either by the (apparent) egg diameter (up to the 10th cleavage) or by half the diameter (from the 10th cleavage onwards) was determined. The cell numbers for each cleavage cycle did not overlap with those of the previous or succeeding cycles. On the basis of these cell numbers, in place of the four Harrison stages 6–9, 10 successive stages were established each of which corresponds to one cleavage cycle.     

Mode of uptake of sterol by Arthrobacter simplex

The mechanism of uptake of water-insoluble -sitosterol by a newly isolated strain of Arthrobacter simplex SS-7 was studied. The production of an extracellular sterol-pseudosolubilizing protein during growth of A. simplex on -sitosterol was demonstrated by isolating the factor from the cell-free supernatant and its subsequent purification by Sephadex G-150 column chromatography. The M _r of the purified sterol-pseudosolubilizing protein determined by SDS–PAGE was 19kDa. The rate of sterol pseudosolubilization (5.2×10^–3g l^–1h^–1) could not adequately account for the rate of sterol uptake (72×10^–3g l^–1h^–1) and the specific growth rate (56×10^–3 h^–1). However in the unfavourable growth condition, when the cells were treated with sodium azide at the level of 30–60% of MIC, the sterol pseudosolubilization accounted for nearly 74% of the total growth containing 96% free cells. Cellular adherence to substrate particles was found to play an active role in the normal growth of the strain on -sitosterol. Unlike sodium acetate-grown cells, whose surface activity was negligible (60mNm^–1), the sterol-grown cells had strong surface activity (40mNm^–1). The high lipid content and long chain fatty acids in the cell-wall of -sitosterol-grown cells probably contribute to the high sterol adherence activity of the cells.     

A fluorometric assay of ceramide glycanase with 4-methylumbelliferyl β-d-lactoside derivatives

4-Methylumbelliferyl 6-O-benzyl--d-lactoside (6Bn-MU-Lac) and some related compounds were synthesizedvia different selective reactions including phase-transfer glycosylation. Their suitability as substrates for a fluorometric assay of ceramide glycanase (CGase) was evaluated. Among others, the 6Bn-MU-Lac, which is resistant to exogalactosidase, was found to be a suitable substrate for routine assay of the CGase activity. For American leech CGase, theK _m value is 0.232 mM at pH 5. Abbreviations: CGase, ceramide glycanase; Gal, galactose; Glc, Glucose; Lac, lactose; MU, 4-methylumbelliferone; MU-Lac, 4-methylumbelliferyl -d-lactoside; bBn-Lac, 6-O-benzyl-lactose; 6Bn-MU-Lac, 4-methylumbelliferyl 6-Obenzyl--d-lactoside; 46Bd-MU-Lac, 4-methylumbelliferyl 4,6-O-benzylidene--d-lactoside; MU-Cel, 4-methylumbellifery -d-cellobioside; 46Bd-MU-Cel, 4-methylumbelliferyl 4,6-O-benzylidene--d-cellobioside; TLC, thin layer chromatography;¹H-NMR, proton nuclear magnetic resonance; GSL, glycosphingolipids; CSA, 10-camphorsulfonic acid. See Scheme 1 for chemical structures.     

A Cytogenetic Study of the Leaf Beetle Genus Cyrtonus (Coleoptera, Chrysomelidae)

The chromosomes of ten species of Cyrtonus and the genome sizes of six are surveyed. Among the total of 15 chromosomally studied species, 11 have 2n=28 chromosomes and a 13+Xy_p male meioformula, three have 2n=40 and 19+Xy_p and one 2n=46 and 22+Xy_p. All but one species with 28 chromosomes show only metacentric or submetacentric chromosomes, whereas the species with 40 and 46 chromosomes display some telocentrics or subtelocentrics, that are probably derived from the former by centric fissions. However, since the number of major chromosome arms is strikingly higher in these latter species (NF=70 and 78) than in the 28-chromosome species (mostly NF=56), other chromosomal rearrangements such as pericentric inversions or heterochromatin accretions could also be involved. The genome sizes display a narrow range, from 1C=0.6–1.22pg, and they are not significantly correlated with the chromosome numbers. Some possible factors implied in the rough chromosomal evolution of Cyrtonus are discussed in relation to a few other genera of the subfamily Chrysomelinae.     

Differences of the electrical and nicotinic receptor stimulation-evoked liberation of norepinephrine from chicken sympathetic neurons in culture: Possible involvement of different pools of the transmitter

We studied the release of [³H]norepinephrine from chicken sympathetic neurons in culture evoked by nicotinic and electrical stimulation with an intention to establish functional identity or nonidentity of the two stimuli in investigations of neurotransmitter release. Nicotinic stimulation evoked extracellular calcium dependent release of [³H]norepinephrine and the rise of intracellular calcium concentration. The release was completely blocked by nicotinic antagonists hexamethonium (100 mol/l) and mecamylamine (10 mol/l), and decreased by tetrodotoxin (0.3 mol/l) and -conotoxin (0.1 mol/l) to 17% and 27%, resp. The intracellular calcium response was decreased by nicotinic antagonists and tetrodotoxin, but not changed by -conotoxin. The electrical stimulation-evoked release was blocked by both tetrodotoxin and -conotoxin, and decreased by previous electrical, but not nicotinic, stimulation. The differential sensitivity to -conotoxin and tetrodotoxin, and the inability of nicotinic stimulation to decrease the liberation by following electrical stimulation may suggest the mobilization of different pools of the transmitter.     

Existence and uniqueness of a sharp travelling wave in degenerate non-linear diffusion Fisher-KPP equations

In this paper we use a dynamical systems approach to prove the existence of a unique critical value c ^* of the speed c for which the degenerate density-dependent diffusion equation u _ct = [D(u)u _x ] _x + g(u) has: 1. no travelling wave solutions for 0 < c < c ^*, 2. a travelling wave solution u(x, t) = (x - c ^* t) of sharp type satisfying (– ) = 1, () = 0 ^*; '(^*–) = – c ^*/D'(0), '(^*+) = 0 and 3. a continuum of travelling wave solutions of monotone decreasing front type for each c > c ^*. These fronts satisfy the boundary conditions (– ) = 1, '(– ) = (+ ) = '(+ ) = 0. We illustrate our analytical results with some numerical solutions.     

A novel cilia-based feature within the food grooves of the ctenophore Mnemiopsis mccradyi Mayer

We describe a novel compound ciliary structure (g-cilium) from the food groove of the lobate ctenophore Mnemiopsis mccradyi. G-cilia are small, flat compound ciliary organelles that are oriented with their tips pointing toward the mouth. Typically three to four rows of g-cilia line the inner surface of the tentacular groove, which together with the transport groove, make up the food groove. G-cilium cells are 11.4 m long and 4.2 m wide at the g-cilium base. The g-cilium itself is 3.4 m long and tapers to a flat, sharp tip. G-cilia are not motile but are surrounded by many hundreds of smaller, actively motile cilia that beat with orally-directed effective strokes. G-cilia contain 50 conventional `9+2' cilia embedded in a fibrous core that arises from the cell body. In addition, g-cilia contain mitochondria, thousands of small membrane-bounded vesicles and rod bacteria. G-cilia basal bodies are anchored by large, strongly-banded rootlets that extend approximately the entire length of the cell. G-cilia may have organizational, sensory and/or secretory function within the feeding apparatus. Their placement strongly suggests that they play critical roles in feeding. They may enhance the efficiency of prey capture and so contribute to M. mccradyi's well-known voracious appetite. By enhancing prey capture they probably play a critical role in the capacity of this organism to follow prey dynamics, so contributing to dense blooms in mid-late summer in coastal regions.     

Die Hypokotylfarbe als Markierungsfaktor von Genomstufen der Zuckerrübe

Zusammenfassung In zunehmendem Maße werden anisoploideBeta-Rübensorten angebaut, deren zytologische Kontrolle zwecks Feststellung der Genomstufenprozentanteile recht arbeitszeitaufwendig ist. Übereinstimmend mit polnischen Autoren wurde festgestellt, daß die Hypokotylfarbe ein geeigneter Markierungsfaktor für die einzelnen Genomstufen darstellt. Kreuzt man tetraploide Pflanzen, die ein grünes Hypokotyl besitzen, mit diploiden Pflanzen, die ein rosa Hypokotyl aufweisen, so erhält man von dem tetraploiden Partner tetraploide grüne und triploide hellbraune, von dem diploiden Partner diploide rosa und triploide hellbraune Nachkommenschaften. Die in bezug auf die Hypokotylfarbe heterozygoten Pflanzen kann man demnach von den homozygot grünen und homozygot rosa Individuen unterscheiden. Die Kreuzung diploid grünxtetraploid rosa ist für diese Zwecke nicht brauchbar, da sich die triploiden Heterozygoten mit einem grünen und zwei rosa Allelen in der Hypokotylfarbe nicht deutlich von den homozygoten rosa Pflanzen abheben. Auf die Bedeutung dieser Markierungsmöglichkeit für bestimmte Forschungsprobleme, die Züchtung und die Saatgutkontrolle wird hingewiesen.     

Colony cycle of an Australian swarm-founding paper wasp,Ropalidia romandi (Hymenoptera: Vespidae)

Summary Colonies of an Australian swarm founding polistine wasp,Ropalidia romandi, on the Atherton Tableland, Queensland, manage perennial nests by practicing seasonal colony activity. In summer nests, most cells were occupied by immatures of all developmental stages. The proportion of cells that did not contain immatures increased towards winter, when most nest cells did not contain immatures and half of these winter nests had rather large amounts of nectar deposited in empty cells. While the visits to tree flowers byR. romandi were not frequent in summer, nearly 60 % of insects collected on tree flowers in winter wereR. romandi. With such seasonal switching in the modes of colony reproductive activity and of nectar foraging behavior,R. romandi responds to its physical and biotic environment. In this way,R. romandi may be able to continue colonies throughout the year, with much reduced level of colony activity in winter, in areas with seasons that are unfavorable for reproductive activity of a colony.     

Identification of beta subunit of the rhesus monkey chorionic gonadotropin (rmCG)

Chorionic gonadotropin (CG) is a placental derived hormone that plays a crucial role in successful implantation and establishment of early pregnancy in the primates. The rhesus monkey was chosen as a model to understand the feasibility of developing human DNA immuno-contraceptive. The coding region of rhesus monkey CG -subunit (rmCG) was isolated by the TDRT-PCR method. The nucleotide sequence including the leader peptide was 499 nucleotide long and encoded 166 amino acids. In comparing with the previous known primates CG -subunits, the rmCG was the highest degree of homology with baboon CG -subunit at the deduced amino acid sequence (94%), 79.5% homology with human CG -subunit and 70.4% homology with marmoset monkey CG -subunit. The eukaryotic expression vector pCMV4-rmCG inserted full-coding cDNA sequence of rmCG was constructed, and the expression of rmCG -subunit in HeLa cells transient expressing system in vitro and BALB/c mice in vivo was determined. The results demonstrated that the recombinant PCMV4-rmCG eukaryotic expression vector could express rmCG -subunit in vitro and in vivo.     

Evidence of regional differences in the lectin histochemistry along the ductus epididymis of the lizard,Podarcis sicula Raf

The regional difference in the carbohydrate components of the ductus epididymis epithelium of a lizard was delineated by means of 13 lectins. Basal cells expressed only N-acetylglucosamine (GlcNAc). Throughout the ductus, the secretory cells showed oligosaccharides with terminal N-acetylneuraminic acid (Neu5Ac)(2,6)galactose (Gal)/N-acetylgalactosamine (GalNAc) and internal mannose (Man) and/or glucose (Glc) in the whole cytoplasm, oligosaccharides terminating in Neu5Ac(2,6)Gal(1,3)GalNAc, Neu5Ac(2,6)Gal (1,4)GlcNAc, GalNAc, GlcNAc, and fucose (Fuc) in the supra-nuclear zone, and also glycans terminating in Neu5Ac(2,3)Gal (1,4)GlcNAc, Neu5Ac(2,6)Gal(1,3)GalNAc, Gal (1,4)GlcNAc on the luminal surface. In the caput and corpus regions, the supra-nuclear cytoplasm was characterized by terminal Gal(1,4)GlcNAc and GalNAc, the luminal surface by GalNAc and Gal. The Golgi zone, showing oligosaccharides with terminal Neu5Ac(2,3)Gal (1,4)GlcNAc, Neu5Ac(2,6)Gal (1,3)GalNAc, Neu5Ac(2,6)Gal (1,4)GlcNAc, and internal GlcNAc, expressed terminal Gal (1,4)GlcNAc and GalNAc in the caput, and terminal GalNAc in the corpus. The granules showed all the investigated carbohydrates in their peripheral zone except terminal GalNAc and Fuc, whereas internal Man/Glc and terminal Gal were expressed in the central core, and Fuc throughout the ductus, terminal GlcNAc in the caput and corpus, and terminal GalNAc only in the corpus.     

Enzymic activities and galactomannan mobilisation in germinating seeds of fenugreek (Trigonella fœnum-graecum L. Leguminosae)

Summary The activities of -galactosidase, -mannosidase and -mannosidase were determined in extracts from the endosperm and from the embryo of fenugreek seeds at different stages of germination. Endosperm homogenates contained little or no activity of the above enzymes in the early stages of germination, before the reserve galactomannan began to be mobilised. The onset of galactomannan breakdown coincided with the appearance of -galactosidase and -mannosidase activities, which increased throughout the period of galactomannan degradation and then remained constant. A similar rise in -galactosidase and -mannosidase activities occurred during galactomannan breakdown in dry-isolated endosperms incubated under germination conditions. The increase could be suppressed by metabolic inhibitors which also inhibit galactomannan breakdown. Embryo homogenates contained high -galactosidase, high -mannosidase and some -mannosidase activity at all stages of germination.No oligomannosyl -1,4 phosphorylase activity could be detected either in the endosperm or in the embryo.It is concluded that the galactomannan of fenugreek is broken down by a series of hydrolases secreted by the aleurone layer of the endosperm. They include -galactosidase, -mannosidase and probably also endo--mannanase.This is part four in a series of papers dealing with galactomannan metabolism. Part three: Planta (Berl.) 106, 44–60 (1972).     

Solution conformations of proline rings in proteins studied by NMR spectroscopy

Summary Three different conformations of proline rings in a protein in solution, Up, Down and Twist, have been distinguished, and stereospecific assignments of the pyrrolidine -, - and -hydrogens have been made on the basis of ¹H-¹H vicinal coupling constant patterns and intraresidue NOEs. For all three conformations, interhydrogen distances in the pairs -³, ³-³, ²-², ²-², and ³-³ (2.3 Å) are shorter than those in the pairs -², ²-³, ³-², ²-³, and ³-² (2.7–3.0 Å), resulting in stronger NOESY cross peaks. For the Up conformation, the ³-² and ²-³ spin-spin coupling constants are small (<3 Hz), and weak cross peaks are obtained in a short-mixing-time (10 ms) TOCSY spectrum; all other vicinal coupling constants are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. For the Down form, the -², ²-³, and ³-² vicinal coupling constants are small, leading to weak TOCSY cross peaks; all other couplings again are in the range 5–12 Hz, and result in medium to strong TOCSY cross peaks. In the case of a Twist conformation, dynamically averaged coupling constants are anticipated. The procedure has been applied to bovine pancreatic trypsin inhibitor and Cucurbita maxima trypsin inhibitor-V, and ring conformations of all prolines in the two proteins have been determined.     

Photoreversion und Photoprotektion bei UV-induzierten Mutationen des nichtphotoreaktivierbaren Bacteriums E.coli phr?

Summary Stationary phase cells of strain phr^–/MC 2 ofE. coli are not photoreactivable but the frequency of UV-induced mutations to low Streptomycine-resistance (S 3, 3/ml) is decreased strongly by illumination with light of fluorescence tubes (310 to 500 nm) after UV-irradiation. Also dark-reversion (DRM) of these mutations due to keeping UV-irradiated cells in saline is observed. Illumination before UV-irradiation decreases the frequency of the mutations (photoprotection against mutation=PPM) to the same extent as the combined action of photoreversion (PRM) and DRM. The lag-phase of cell division is prolonged strongly by illumination from 80 min without light to 150 min by the light-dose of highest activity. The additional lag is nearly the same if the illumination is done before, after or without UV-irradiation; this lag is about additive to the small lag caused by UV. Pre-illumination of the stationary-phase cells does not cause photoprotection against killing (PP), it even decreases the survival after high UV-doses. The observations support the hypothesis that PRM in this strain may be indirect, i.e. caused by the light-induced additional division lag which enhances the dark repair of UV-premutations. Also spontaneous premutations which are apparently present in the stationary-phase cells seem to be influenced by the light in this way.     

Evolution alpiner Populationen vonEuphrasia (Scrophulariaceae): Die mittel- bis kleinblütigen,drüsenhaarigen Arten

A more precise taxonomic concept ofE. hirtella and its infraspecific synonymy is presented. Its diploid nature (2n = 22) is confirmed. Within the European area ofE. hirtella five different races may be recognised: typical, brandisii, capitulata, Rofan and Bretagne. Taxonomic rank is not yet attributed to these races. The heterogeneous taxonomic assembly E. drosocalyx is disentangled. The type refers to products of hybrid introgression ofE. rostkoviana-characters (long glandular hairs) intoE. minima.

Former contributions of this series areEhrendorfer & Vitek (1984) andGreilhuber & al. (1984).