Autologous tumor vaccines processed to express α-gal epitopes: a practical approach to immunotherapy in cancer

This review describes a method by which the human natural anti-Gal antibody can be exploited as an endogenous adjuvant for targeting autologous tumor vaccines to antigen-presenting cells (APCs). Tumor cells remaining in the patient after completion of surgery, radiation, and chemotherapy are the cause of tumor relapse. These residual tumor cells can not be detected by imaging, but their destruction may be feasible by active immunotherapy. Since specific tumor-associated antigens (TAAs) have not been identified for the majority of cancers, irradiated autologous tumor vaccines have been considered as an immunotherapy treatment that may elicit an immune response against the residual tumor cells expressing TAAs. However, tumor cells evolve in cancer patients in a stealthy way, i.e., they are not detected by APCs, even in the form of vaccine. Effective targeting of tumor vaccines for uptake by APCs is a prerequisite for eliciting an effective immune response which requires transport of the vaccine by APCs from the vaccination site to the draining lymph nodes. In the lymph nodes, the APCs transporting the vaccine process and present peptides, including the autologous TAA peptides for activation of the tumor-specific T cells. The required targeting of vaccines to APCs is feasible in humans by the use of anti-Gal. This antibody interacts specifically with the -gal epitope (Gal1-3Gal1-4GlcNAc-R) and is the only known natural IgG antibody to be present in large amounts in all humans who are not severely immunocompromised. The -gal epitope can be synthesized on any type of human tumor cell by the use of recombinant 1,3galactosyltransferase (1,3GT). Solid tumors obtained from surgery are homogenized and their membranes subjected to -gal epitope synthesis. Similarly, -gal epitopes can be synthesized on intact tumor cells from hematological malignancies. Administration of irradiated autologous tumor vaccines processed to express -gal epitopes results in in situ opsonization of the vaccinating cells or cell membranes due to anti-Gal binding to these epitopes. The bound antibody serves to target the autologous tumor vaccine to APCs because the Fc portion of the antibody interacts with Fc receptors on APCs. Since patients receive their own TAAs, the vaccine is customized for autologous TAAs in the individual patient. The repeated vaccination with such autologous tumor vaccines provides the immune system of each patient with an additional opportunity to be effectively activated by the autologous TAAs. In some of the immunized patients this activation may be potent enough to induce an immune-mediated eradication of the residual tumor cells expressing these TAAs.Abbreviations Ab Antibody - Ag Antigen - APC Antigen-presenting cell - DC Dendritic cell - FcR Fc receptor - -gal epitope Gal1-3Gal1-4GlcNAc-R - 1,3GT -1,3-Galactosyltransferase - KO mice Knockout mice for 1,3GT - OVA Ovalbumin - SA Sialic acid - TAA Tumor-associated antigen     

Preparation of a series of sulfated tetrasaccharides from shark cartilage chondroitin sulfate D using testicular hyaluronidase and structure determination by 500 MHz1H NMR spectroscopy

Six tetrasaccharide fractions were isolated from shark cartilage chondroitin sulfate D by gel filtration chromatography followed by HPLC on an amine-bound silica column after exhaustive digestion with testicular hyaluronidase. Their structures were determined unambiguously by one- and two-dimensional 500 MHz¹H NMR spectroscopy in conjunction with HPLC analysis of chondroitinase AC-II digests of the tetrasaccharides. One fraction was found to contain two tetrasaccharide components. All the seven tetrasaccharides shared the common core structure GlcA1-3GalNAc1-4GlcA1-3GalNAc with various sulfation profiles. Four were disulfated comprising of two monosulfated disaccharide units GlcA1-3GalNAc(4-sulfate) and/or GlcA1-3GalNAc(6-sulfate), whereas the other three were hitherto unreported trisulfated tetrasaccharides containing a disulfated disaccharide unit GlcA(2-sulfate)1-3GalNAc(6-sulfate) and a monosulfated disaccharide unit GlcA1-3GalNAc(4-or 6-sulfate). These sulfated tetrasaccharides were demonstrated to serve as appropriate acceptor substrates for serum -N-acetylgalactosaminyltransferase, indicating their usefulness as authentic oligosaccharide substrates or probes for the glycobiology of sulfated glycosaminoglycans.Abbreviations NFU National formulary unit - COSY correlation spectroscopy - HOHAHA homonuclear Hartmann-Hahn - 1D or 2D one- or two-dimensional - IdoA l-iduronic acid - GlcA d-gluco-4-enepyranosyluronic acid - Di-0S GlcA1-3GalNAc - Di-4S GlcA1-3GalNAc(4-sulfate) - Di-4S GlcA1-3GalNAc(4-sulfate) - Di-6S GlcA1-3GalNAc(6-sulfate) - Di-6S GlcA1-3GalNAc(6-sulfate) - Di-diS _d GlcA(2-sulfate)1-3GalNAc(6-sulfate) - Di-diS_E GlcA1-3GalNAc(4, 6-disulfate) - U G, U, 2S, 4S, and 6S represent GlcA, GalNAc, GlcA, 2-O-sulfate, 4-O-sulfate, and 6-O-sulfate, respectively     

Cloning theClostridium thermocellum thermostable laminarinase gene inEscherichia coli: The properties of the enzyme thus produced

Summary We have cloned a 1.9-kb-long fragment ofClostridium thermocellum DNA which encodes laminarinase (EC 3.2.1.39). The enzyme hydrolyzes the -1,3-glucoside bonds in -1,3-and in mixed -1,3-1,4-polyglucans. The enzyme's optimum pH value is around 8.5, temperature optimum –70°C. PAGE-determined mol. weight –32 kDa.Abbreviations used CMC carboxymethyl cellulose - pNPC p-nitrophenyl D cellobioside - pNPLac p-nitrophenyl- D-lactoside - pNPG p-nitrophenyl D glucopyranoside - pNPGal p-nitrophenyl- D galactopyranoside - pNPXyl p-nitrophenyl- - D xylopyranoside - Ap ampicillin - SDS-PAGE SDS polyacrylamide gel electrophoresis     

Natural abundance of 15N in tropical plants with emphasis on tree legumes

Natural abundance of ¹⁵N ( ¹⁵N) of leaves harvested from tropical plants in Brazil and Thailand was analyzed. The ¹⁵N values of non-N₂-fixing trees in Brazil were +4.5±1.9, which is lower than those of soil nitrogen (+8.0±2.2). In contrast, mimosa and kudzu had very low ¹⁵N values (–1.4+0.5). The ¹⁵N values of Panicum maximum and leguminous trees, except Leucaena leucocephala, were similar to those of non-N₂-fixing trees, suggesting that the contribution of fixed N in these plants is negligible. The ¹⁵N values of non-N₂-fixing trees in Thailand were +4.9±2.0. Leucaena leucocephala, Sesbania grandiflora, Casuarina spp. and Cycas spp. had low ¹⁵N values, close to the value of atmospheric N₂ (0), pointing to a major contribution of N₂ fixation in these plants. Cassia spp. and Tamarindus indica had high ¹⁵N values, which confirms that these species are non-nodulating legumes. The ¹⁵N values of Acacia spp. and Gliricidia sepium and other potentially nodulating tree legumes were, on average, slightly lower than those of non-N₂-fixing trees, indicating a small contribution of N₂ fixation in these legumes.     

Effects of supplied cinnamic acids and biosynthetic intermediates on the anthocyanins accumulated by wild carrot suspension cultures

Anthocyanins isolated and characterized from the wild carrot suspension cultures used here were 3-O--D-glucopyranosyl-(16)-[-D-xylopyranosyl-(12)-]-D<-galactopyranosylcyanidin (1), 3-O-[-D- xylopyranosyl-(12)--D-galactopyranosyl]cyanidin (2), 3-O-(6-O-sinapoyl)--D-glucopyranosyl-(16)-[-D- xylopyranosyl-(12)-]-D-galactopyranos ylcyanidin (3), 3-O-(6-O-feruoyl)--D-glucopyranosyl-(16)-[- D-xylopyranosyl-(12)-]-D-galactopyranosylcyanidin (4), 3-O-(6-O-coumaroyl)--D-glucopyranosyl-(16)- [-D-xylopyranosyl-(12)-]-D-galactopyrano sylcyanidin (5), 3-O-[6-O-(3,4,5-trimethoxycinnamoyl)]-- D-glucopyranosyl-(16)-[-D-xylopyranosyl-(12)-]-D-galactopyranosylcyanidin (6), 3-O-[6-O-(3,4-dime- thoxycinnamoyl)]--D-glucopyranosyl-(16)-[-D-xylopyranosyl-(12)-]-D-galactopyranosylcyanidin (7), 3-O-[(6-O-sinapoyl)--D-glucopyranosyl-(16)--D-galactopyranosyl]cyanidin (8), and 3-O-(-D-galactopyranosyl)cyanidin (9). Except when cinnamic acids were provided in the culture medium, the major anthocyanin present in the two clones examined was 2. When the naturally occurring and some non-naturally occurring cinnamic acids were provided individually in the medium, 1 and 2 were minor components and the anthocyanin acylated with the supplied cinnamic acid, namely 3, 4, 5, 6, or 7 was the major anthocyanin present in the tissue. When caffeic acid was provided the major anthocyanin in the tissue was 4, thereby suggesting that the caffeic acid was methylated before its use in anthocyanin biosynthesis. Other cinnamic acids supplied had limited effects on the anthocyanins accumulated and appeared not to result in the accumulation of new anthocyanins by the tissue. Thus the tissue can use some but not all analogues of sinapic acid to acylate anthocyanins. Additional anthocyanins were detected in extracts of the wild carrot tissue cultures using mass spectrometry (both MS/MS and HPLC/MS). The additional compounds detected have also been found in cultures of black carrot, an Afghan cultivar of Daucus carota ssp. sativa and the flowers of wild carrot giving no evidence for qualitative differences in the anthocyanins synthesized by subspecies, cell cultures from subspecies, or clones from cell cultures. There are major differences in the amounts of individual anthocyanins found in cultures from different subspecies and in different clones from cell cultures. Here anthocyanins without acyl groups were usually found in the tissues and their accumulation is discussed. On the basis of the structures of the isolated anthocyanins, a likely pathway from cyanidin to the accumulated anthocyanins is proposed and discussed.Abbreviations Sin sinapoyl - Fer feruoyl - 4-Coum. 4-coumaroyl - 3,4-MeO₂Cin 3,4-dimethoxyeinnamoyl - 3,4,5-MeO₃Cin 3,4,5-trimethoxycinnamoyl - Cya cyanidin     

ζ-Carotene<Emphasis Type="Italic"> cis</Emphasis> isomers as products and substrates in the plant poly-<Emphasis Type="Italic">cis</Emphasis> carotenoid biosynthetic pathway to lycopene

The plant carotenoid biosynthetic pathway to cyclic carotenes proceeds via carotene precursors in cis configuration. Involvement of individual isomers was elucidated by genetic complementation of desaturations and in vitro reactions of the corresponding enzyme. Determination of substrate and product specificity of phytoene and -carotene desaturase revealed that 15-cis-phytoene is converted to 9,15,9-tricis--carotene with 15,9-dicis-phytofluene as intermediate by the first desaturase. Prior to a subsequent conversion by -carotene desaturase, the 15-cis double bond of 9,15,9-tricis--carotene has to be (photo)isomerized to all-trans. Then, the resulting 9,9-dicis--carotene is utilized by -carotene desaturase via 7,9,9-tricis-neurosporene to 7,9,7,9-tetracis-lycopene. Other -carotene isomers that are assumed to be spontaneous isomerization products were not converted, except for the asymmetric 9-cis--carotene. This isomer is desaturated only to 7,9-dicis-neurosporene resembling a dead-end of the pathway. Prolycopene, the product of the desaturation reactions, is finally isomerized by a specific isomerase to all-trans-lycopene, which is a prerequisite for cyclization to -carotene. The 5-cis-lycopene and the 9-cis-and 13-cis--carotene isomers detected in leaves are thought to originate independently from cis precursors by non-enzymatic isomerization of their all-trans forms.     

Microbial transformation of ginsenoside Rb1 by Rhizopus stolonifer and Curvularia lunata

Of 49 microbial strains screened for their capabilities to transform ginsenoside Rb₁, Rhizopus stolonifer and Curvularia lunata produced four key metabolites: 3-O-[-d-glucopyranosyl-(1,2)--d-glucopyranosyl]- 20-O-[-d-glucopyranosyl]-3,12, 20(S)-trihydroxydammar-24-ene (1), 3-O-[-d-glucopyranosyl-(1,2)--d- glucopyranosyl]-20-O-[-d-glucopyranosyl]-3,12, 20(S)-trihydroxydammar-24-ol (2), 3-O-[-d-gluco- pyranosyl-(1,2)--d-glucopyranosyl]-3, 12, 20(S)-trihydroxydammar-24-ene (3), and 3-O--d-glucopyranosyl-3, 12, 20(S)-trihydroxydammar-24-ene (4), identified by TOF-MS, ¹H- and ¹³C-NMR spectral data. Metabolites 1, 3 and 4 were from the incubation with R. stolonifer, and 1 and 2 from the incubation with C. lunata. Compound 2 was identified as a new compound.     

Assortative mating and the genetic correlation

Summary The effect of assortative mating on the genetic correlation between traits X and Y is considered. Assortation on trait X changes the magnitude of the genetic correlation but not its sign. There are two situations depending on the signs of the correlation between mates () and of the random mating genetic correlation (): 1) if sign () = sign (), then >, where is the genetic correlation at equilibrium after continued assortation, and 2) if sign () = sign (), then < . However, negative assortative mating is virtually powerless to alter the magnitude of the genetic correlation. The consequences of a mixed assortation model, e.g., high milk production females mated to fast growing males and lesser productive females mated to slower growing sires, were also studied. Mixed positive assortation always increases the genetic correlation, but negative assortation decreases it. The implications of assortative mating on correlated responses to selection and on the equilibrium covariances between relatives for pairs of traits are discussed.     

A model for light adaptation: Producing Weber's law with bleaching-type kinetics

An adaptation model having two stages is introduced and its mathematical properties are examined. The two stages are the adaptive process (parameter K _b), which has bleaching-type kinetics, and the response function (parameters K _r and n), which incorporates response saturation. In order to study the increment threshold functions generated by the adaptation model the concept of a detector is required. It is demonstrated that without an adaptive process the compression hypothesis, in the form of the difference equation, produces increment threshold functions which saturate and do not obey Weber's law. It is then shown that an adaptive process with bleaching-type kinetics can prevent saturation and produce Weber's law behavior provided that the adaptive strength of the system exceeds the detector sensitivity.     

Die bursa- und schwanzstrukturen und ihre aberrationen bei den strongylina (Nematoda) morphologische studien zum problem der pluri-und paripotenzerscheinungen

Zusammenfassung In der Einleitung ist das Ziel der Arbeit in den wesentlichsten Punkten herausgestellt.Die Bursastrukturen (Bursavelum und Rippen bzw. Papillen) der parasitischen Strongylina lassen sich von den entsprechenden Bildungen der freilebenden Rhabditina, vor allem der Gattung Rhabditis, ableiten und in ihren Einzelgliedern homologisieren.Die im Laufe der Phylogenie bei den Strongylina auftretenden strukturellen Transformationen lassen sich auf einige wenige, relativ einfache morphogenetische Grundvorgänge zurückführen, die da sind: Wachstumsallometrien, Materialkompensationen, Organverschmelzungen und Spaltungen (Fissationen), Rudimentationen und ähnliche Vorgänge.Innerhalb der Strongylina Bursa ist ein Gefälle der Wachstumsgradienten feststellbar, das sich vom Zentrum der Bursa sowohl nach distal als auch proximalwärts abschwdcht. Zunehmende Förderung der zentral gelegenen Organe (Rippen) führt zu entsprechender Reduktion der peripheren Bursastrukturen, was vor allem im terminalen Schwanzabschnitt auffällt und zur Ausbildung des oft nur noch als Rudiment vorhandenen Dorsalrippenkomplexes führt. Letzterer entspricht in seiner Gesamtheit der Schwanzspitze der peloderen Rhabditiden mit den Papillen 9 und 10.Die bei Rhabditis moist getrennten Papillen 7 und 8 sind bei allen Strongylina zu einer Rippe (Externodorsal-Rippe) verschmolzen, die jedoch in manchen Aberrationen durch Abspaltung eines akzessorischen Astes ihre wahre Natur (als Verschmelzungsprodukt) zu erkennen gibt (Atavismus).Da dieselben Transformationsvorgänge innerhalb der Strongylina mehrfach unabhängig voneinander wirksam geworden sind, treten bestimmte Strukturformen als Parallelbildungen in verschiedenen phylogenetischen Union auf (polytope Entstehung).Zahlreich untersuchte Bildungsabweichungen (Aberrationen), deren Bedeutung für die Morphologie kurz umrissen wird, erschöpfen sich in den gleichen strukturellen Transformationstypen, die auch bei der Evolution der verschiedenen Union der Strongylina nachweisbar sind. Die Aberrationen führen daher häufig zu Atavismen oder zu Parallelvariationen (homologe Variationen").Die Zahl der Umwandlungsmbglichkeiten (Potenzen) der Bursastrukturen innerhalb der Strongylina ist beschränkt (Paripotenz im Sinne Haeckers). Bestimmte Arten (und Entwicklungshnien) haben jeweils nur bestimmte Potenzen realisiert. Andere können jedoch latent (virtuell) im Kryptotypus vorhanden sein, ohne normalerweise in Erscheinung. zu treten. In bestimmten Aberrationen können sie jedoch plötzlich realisiert werden, so ihr latentes Vorhandensein demonstrierend (Pluripotenz).Wie lange bestimmte Potenzen in einer Gruppe erhalten bleiben konnen, verdeutlichen auch die Schwanzhocker weiblicher Nematoden, als zum Bauplan der Nematoden gehbrende Bildungen. Die Potenz zur Ausbildung dieser Strukturen kommt offensichtlich sehr vielen Nematoden-Arten zu, wird jedoch nur in relativ wenigen Fällen, aber innerhalb der verschiedenen Gruppen bald hier, bald dort (disjunkte Verbreitung), realisiert. Es handelt sich bei den Schwanzhöckern um rudimentäre Organe, die bei keiner Nematoden-Art mehr voll ausgebildet erhalten sind. Ihre Rudimentation beruht zum Teil auf Materialentzug, als Folge von Unkonstruktionen der Schwanzregion, wobei die Adultstadien zuerst betroffen werden (Aphanisie nach Sewertzoff).Bei den in Chiropteren parasitierenden Strongylacanthinae haben sich Schwanzhöcker noch bei allen Arten erhalten, was ein offensichtlich archaisches Merkmal darstellt. Bei anderen Nematoden, denen sie nur im Larvalstadium zukommen, treten sie wohl durch Fötalisation in seltenen Fällen auch bei den adulten Stadien wieder auf.Alle speziellen Bursaformen der Strongylina lassen sich durch relativ wenige und einfache Transformationsvorgänge aus einem durch Abstraktion gewonnenen diagrammatischen Typus ableiten (Prinzip der variablen Proportionen" nach Troll).Die typisierten Umwandlungsvorgänge decken sich weitgehend mit den von Remane allgemein gefaßten strukturellen Typen der Realmutationen. Da sie bei den beobachteten Aberrationen, deren Entstehung auf dem Wege über Realmutationen sehr wahrscheinlich ist, in homologer Weise auftreten, kann das innerhalb der Strongylina zu beobachtende Evolutionsphänomen auf Realmutationen zurückgeführt warden.Obwohl sich die untersuchten strukturellen Transformationen in dem systematisch relativ wait gefaßten Rahmen einer Unterordnung abspielen (transspezifische Evolution nach Rensch), handelt es sich bei der von uns bevorzugten Terminologie (nach Woltereck und Remane), unter Berücksichtigung des Charakters der Umwandlungen, doch nur um Vorgänge, die in den Bereich der Mikroevolution fallen.     

Fortpflanzungsverhalten der Palmtaube (Streptopelia senegalensis): Paarbildung bis Eiablage

Zusammenfassung Die Fortpflanzungsperiode der Palmtaube (Streptopelia s. senegalensis L.) fängt in Diyarbakir/Türkei (37°55N/40°12E) schon Anfang Februar an und kann bis Mitte November dauern. In diesem Zeitraum kann ein Paar bis zu sieben Bruten beginnen (Tab. 1). Nach der Paarbildung fangen die Kopulationen an, die vor allem in der Woche vor der Eiablage stark zunehmen. Während des Brütens und der ersten Woche der Jungenaufzucht sind sie dagegen nicht zu beobachten. Sie werden vom im allgemeinen mit sog. Flügeltippen bzw. Scheinputzen eingeleitet. Nach der Begattung paradiert das um das , das auf der Stelle verharrt. Vor dem Tretakt fällt das dagegen in infantiles Verhalten und bettelt unter Flügelzittern den Partner um Futter an. Es bekommt auch tatsächlich Futter. Die Palmtauben sind zumindest für eine Fortpflanzungssaison monogam. U. a. spielen wechselseitige Gefiederpflege und Anschlußbruten sowie die Fütterung des durch das eine wichtige Rolle für das Zusammenleben und -bleiben der Partner. Der Nistplatz wird vom gezeigt, aber vom gewählt. Das Nistmaterial wird vom eingetragen und im allgemeinen vom alleine in das Nest eingefügt. Nur während des Brutwechsels bringt auch das hin und wieder Nistmaterial, das aber wahrscheinlich nur für den Partner, nicht für das Nest dient. In den späteren Phasen des Brütens gilt dies wahrscheinlich auch für das . 1–4 Tage nach dem Nestbaubeginn wird gegen Abend das erste Ei gelegt, womit auch das Brüten anfängt. Das zweite Ei folgt dann rund 38 Stunden später.

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On the reproductive behaviour of the Laughing Dove (Streptopelia senegalensis): pair-formation to egg-laying

Summary In Diyarbakr/Turkey, the reproductive season of the Laughing Dove begins in early February and lasts til mid November. One pair may start with breeding up to seven times a year. The frequency of copulations which could be observed only after pair formation increased considerably in the week before incubation starts. During incubation and during the first week of the nestling period no copulations could be observed. Usually copulations are initiated by the male pecking behind its folded wings (displacement-preening). Before mating, the female turns into infantile behaviour begging food from its partner by wing-twitching. Food is then delivered by the male. After mating the female parades around the male which stays motionless. Paired birds stay together at least during one reproductive season. Reinforcement of the pair bond will be achieved by mutual preening, courtship feeding of the female by the male, and successive broods. The male indicates the nest site which is successively chosen by the female. The nest material is brought by the male and usually placed by the female at the nest site. Only during change-overs the female sometimes brings nesting material, too. However, this material probably is for the partner, not actually for the nest. The same may be true for similar behaviour of the male in late stages of incubation. One to four days after nest building has started the first egg is laid, mostly in late afternoon. Incubation starts with the first egg; the second egg is laid about 38 hours later.

     

A Comparative Study on Selectivity of α-Conotoxins GI and ImI Using Their Synthetic Analogues and Derivatives

Comparative structure-function studies have been carried out for -conotoxin GI acting on nicotinic acetylcholine receptors (AChR) from mammalian muscles and from the electric organ of the Torpedo californica ray and for -conotoxin ImI, which targets the neuronal a7 AChR. A series of analogs has been prepared for this purpose: chemically modified derivatives, including a covalently linked dimer of GI, as well as analogs wherein one or several amino acid residues have been changed using solid-phase peptide synthesis. The activity of all compounds was assessed in competition with radioiodinated and/or tritiated -conotoxin GI for binding to the membrane-bound AChR of Torpedo californica. Binding of radioiodinated -conotoxin GI dimer was also monitored directly, revealing the largest, as compared to all other analogues, difference in the affinity between the two binding sites in the receptor (K_D 11 and 1200 nM). Comparison of binding data with the results of CD measurements point to important role of the spatial organization of the -conotoxin second loop in manifestation of their muscle or neuronal specificity.     

UDP-galactose:lactosylceramide α-galactosyltransferase activity in human placenta

The activity of UDP-Gal: LacCer galactosyltransferase in human placenta was studied by using crude homogenate and Triton CF-54 extract as the source of enzyme. Transfer of galactose to lactosylceramide was optimal in the presence of 0.1% Triton CF-54 and Mn²⁺ at pH 6.3, and the reaction product was susceptible to -galactosidase.Abbreviations LacCer lactosylceramide (Gal1-4Glc1-1Cer) - Gb₃ globotriaosylceramide (Gal1-4Gal1-4Glc1-1Cer) - Gb₄ globoside (GalNAc1-3Gal1-4Gal1-4Glc1-1Cer) - TLC thin-layer chromatography - GC/MS gas chromatography/mass spectrometry - NMR nuclear magnetic resonance - EDTA ethylenediamine tetraacetic acid - CHAPS 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate     

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.     

Role of mitochondria in ethanol tolerance of Saccharomyces cerevisiae

The presence of active mitochondria and oxidative metabolism is shown to be essential to maintain low inhibition levels by ethanol of the growth rate (), fermentation rate (v) or respiration rate () of Saccharomyces cerevisiae wild type strain S288C. Cells which have respiratory metabolism show K _i (ethanol inhibition constant) values for , v and , higher (K _i>1 M) than those of petite mutants or grande strains grown in anaerobiosis (K _i=0.7 M). In addition, the relationship between or v and ethanol concentration is linear in cells with respiratory metabolism and exponential in cells lacking respiration. When functional mitochondria are transferred to petite mutants, the resulting strain shows K _i values similar to those of the grande strain and the inhibition of and v by increasing ethanol concentrations becomes linear.     

The polarized UV-absorption spectra and the crystal structure of two different monoclinic crystal forms of the retinal homologue β-8′-apocarotenal

During the visual process, light absorption in the 11-cis retinylidene chromophore leads to a rapid cis-trans-isomerization which initiates the phototransduction step. Important spectroscopic properties of this chromophore can be derived from polarized UV-absorption spectra of crystalline 11-cis-retinal if a parallel X-ray structure analysis is performed. Several questions about the relation between molecular geometry and spectroscopic behavior could not be answered from these spectra. All crystal forms of 11-cis-retinal contain this molecule in its 6-s-cis-ring conformation. For the retinal homologue, -8-apocarotenal (APC), however, two crystal forms with different ring conformation can be grown. The spectrum of -APC (6-s-cis) shows a vibronic structure whereas that of -APC (6-s-trans) is diffuse but has a distinct shoulder on the low energy side of the main band. This S-band is typical for retinal spectra and has been ascribed to a transition into a ¹A _g ^-* -state. The appearance of the S-band is not correlated with a 6-s-cis-conformation as suggested by the retinal spectra but is due to intermolecular interactions: -APC has a dense dimer packing and a strong electrostatic interaction between the -electron systems. This might cause the forbidden ¹A _g ^-* -transition. On the other hand, this interaction is missing in the loose and polar packing of -APC which favors vibration in the polyene chain. This finding is remarkable in view of the photodynamic behavior of the visual chromophore for which strong electrostatic interactions with the protein helices of its binding site have to be postulated.Abbreviations APC 8--Apocarotenal - -APC/-APC /-form of crystallized APC - -CIS/-CIS /-form of crystallized 11-cis-retinal - ATR all-trans retinal - UV ultraviolet light - CI quantum-mechanical calculation employing configuration interaction - PPP-MRD quantum-mechanical calculations after Pariser, Parr, Pople employing multireference determinants - S-bands shoulder on main absorption band - R, S right, left enantiomer - EtOH ethyl alcohol - PE petroleum ether - E direction of electric vector of incident light - b crystallographic b-axis     

Multiple Phosphorylation Sites and Quaternary Organization of Guanine-Nucleotide Exchange Complex of Elongation Factor-1 (EF-1βγδ/ValRS) Control the Various Functions of EF-1α

The eukaryotic guanine-nucleotide exchange factor commonly called elongation factor-1 (EF-1), comprises four different subunits including valyl-tRNA synthetase (EF-1/ValRS). The factor is multiply-phosphorylated by three different protein kinases, protein kinase C, casein kinase II and cyclin dependent kinase 1 (CDK1). EF-1/ValRS is organized as a macromolecular complex for which we propose a new structural model. Evidence that EF-1/ValRS is a sophisticated supramolecular complex containing many phosphorylation sites, makes it a potential regulator of any of the functions of its partner EF-1, not only involved in protein synthesis elongation, but also in many other cellular functions.     

Holling's “hungry mantid” model for the invertebrate functional response considered as a Markov process. Part II: Negligible handling time

In this paper we analyse a stochastic model for invertebrate predation taking account of the predator's satiation. This model approximates Holling's hungry mantid model when handling time is negligible (see Part I). For this model we derive equations from which we can calculate the functional response and the variance of the total catch. Moreover we study a number of approximations which can be used to calculate these quantities in practical cases in a relatively simple manner.List of Notation a rate constant of digestion - b maximum of rate constant of prey encounter in the mantid - c satiation threshold for search - c satiation threshold for pursuit in the mantid - c _i (w^1/2(N- N)ⁱ) - expectation operator - f rate of change of satiation during search - F functional response: mean number of prey eaten per unit of time - g rate constant of prey capture - h probability generating function of N conditional on S = s times p - H probability generating function of N - m_i ¹ - n, N number of prey caught - p probability density of S - p_n simultaneous probability (density) of N and S - q probability of strike success - r dummy variable in generating function - s, S satiation - T _s search time - T _d digestion time - v asymptotic rate of increase of var v - V asymptotic rate of increase of var N - w weight of edible part of prey - W standard Wiener process - x prey density - z (N{S = s}-N)p - rate constant of prey escape time maximum pursuit time - (v{S = + w ^1/2}-v) - present time as a fraction of the time from the start to the end of the experiment - hazard rate of T _s - mean time between (downward) passages of S through c - v w_–1/2(N-) - edible prey biomass density - probability density of , number pi - parameter of Weibull distribution of T _s = (1/2acx(-g(c)))_1/2 - w_–1/2(S -) - satiation in the guzzler approximation: solution to d/dt = f() + g(), (0)=S(0). - biomass functional response: wF - total biomass catch in the guzzler approximation: solution to d/dt = g(), (0) = 0     

Studies on the sites expressing evolutionary changes in the structure of eukaryotic 5S ribosomal RNA

Summary We have determined the complete sequences of 5S rRNAs from a lamprey (Lampetra reissneri), a lancelet (Branchiostoma belcheri), silkworms (Philosamia cynthia ricini, Bombyx mori, Antheraea pernyi), and a silkworm hybrid (artificially fertilized hybrid species ofPhilosamia cynthia ricini x Bombyx mori ), as well as those of cotton seeds (Gossypium hirsutum L.). Having compared more than 170 eukaryotic 5S rRNAs of which seven sequences have been determined by our group as mentioned above, we have found that the evolutionary sites that exist at special locations in these structures are closely related to the evolution of eukaryotes. The changes proceed step by step in an orderly way, i.e., the change in nucleotide residues of the evolutionary sites depends on the order of the evolution of the species and shows group-specific patterns.