Polymerization of β-amino Acids in Aqueous Solution

We have compared carbonyl diimidazole (CDI) and 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDAC) as activating agents for the oligomerization of negatively-charged - and -amino acids in homogeneous aqueous solution. -Amino acids can be oligomerized efficiently using CDI, but not by EDAC. -Amino acids can be oligomerized efficiently using EDAC, but not by CDI. Aspartic acid, an - and -dicarboxylic acid is oligomerized efficiently by both reagents. These results are explained in terms of the mechanisms of the reactions, and their relevance to prebiotic chemistry is discussed.     

Food uptake and the fine structure of the dinophytePaulsenella sp. an ectoparasite of marine diatoms

Summary Motile dinospores ofPaulsenella attach to a host diatom frustule, form a feeding tube, drive it between epi- and hypocingulum, pierce the host plasmalemma and suck up host cytoplasm gradually. This mode of endocytosis (myzocytosis) implies that the host plasmalemma is not ingested and that the host cytoplasm within the food vacuole is bounded only by the vacuolar membrane. The feeding tube is formed by the emergence of a preformed microtubular basket consisting of plates of microtubules. At its entrance into the cell body the feeding tube channel is surrounded by an electron-dense ring. Similar sphincters enclose the two exits through which the two flagella emerge. These sphincters are composed of microfibrils which reveal a cross striation when the fixative does not contain calcium ions. The flagellar bases as well as the internal part of the feeding tube are surrounded by a common cavity which is in open connection also with the ampullae of the pusule. The light and electron microscopical observations do not support the assumption that food uptake is driven by a flow of the membrane of the feeding tube channel caused by an interaction with the microtubular basket (as postulated for food uptake inSuctoria) but rather by an hydrostatic gradient which might be caused by rhythmical ion pumping and be based on the existence of the common cavity and the sphincters. Myzocytosis is inhibited by cytochalasin B.—The fine structure of dinospores and trophonts, especially with respect to the cell covering, the amphiesma, and the en- and excystment, is described.     

The “small but healthy” hypothesis: Historical,political, and ecological influences on nutritional standards

How accurate international nutritional standards are for recommending and assessing adequate nutrient intake and nutritional status of different national populations has been debated by nutritionists, economists, and others. This paper reviews the assumptions and possible motivations behind the design and interpretation of standards in particular countries, with a special emphasis on India and Mexico. The analysis suggests that comparative studies of the ethnonutrition concepts of policy-makers are useful for understanding how standards are set, and their nutritional implications.Substantially revised paper originally presented in the symposium Standards and Reference Values: Problems and Pitfalls for Nutritional Anthropologists at the Annual Meeting of the American Anthropological Association, Chicago, Illinois, November 17, 1983.     

Grazing by a dominant rotifer Conochilus unicornis Rousselet in a mountain lake: in situ measurements with synthetic microspheres

Grazing rates of zooplankton were analysed in the summer of 1999 in Yellow Belly Lake, an oligotrophic system in the Sawtooth Mountains of Idaho (U.S.A.). The colonial rotifer Conochilus unicornis was a dominant species in the epilimnion, with densities reaching 20 colonies l^–1 (ca. 400 ind. l^–1). Clearance rates were measured with an in situ Haney Grazing chamber and synthetic microspheres 5, 9 and 23m in diameter. At epilimnetic temperatures of around 14 °C, mean clearance rates for 5m particles ranged from 30 to 65 l ind.^–1 h ^–1. Clearance rates were 2–9 times higher on the 5m spheres than on the 9 m spheres, and C. unicornis almost never fed on the 23 m spheres. Grazing rates did not change over the diel cycle. Clearance rates declined more than 10-fold as temperatures declined from 14 °C in the epilimnion to 7 °C in the metalimnion. In the epilimnion, grazing by C. unicornis was more important than grazing by crustaceans in the community, at least on particles 9m. The results show the importance of grazing by rotifers in lakes, and the significance of spatial variations that influence grazing rates.     

Structural requirements for the binding of oligosaccharides to immobilized lectin ofErythrina variegata (Linn) var.Orientalis

The structural requirements for the interaction of asparagine-linked oligosaccharide moieties of glycoproteins withErythrina variegata agglutinin (EVA) were investigated by means of affinity chromatography on an EVA-Sepharose column. Some of the branched poly-N-acetyllactosamine-type oligosaccharides obtained from human erythrocyte band 3 glycoprotein were found to show high affinity to EVA-Sepharose, whereas complex-type oligosaccharides were shown to have low affinity. Hybrid type, oligomannose-type and unbranched poly-N-acetyllactosamine-type oligosaccharides bound very little or not at all to EVA-Sepharose. To further study the carbohydrate-binding specificity of this lectin, we investigated the interaction of immobilized EVA and oligosaccharide fragments obtained through partial hydrolysis from branched poly-N-acetyllactosamine-type oligosaccharides. Branched poly-N-acetyllactosamine-type oligosaccharides were subjected to limited hydrolysis with 0.1% trifluoroacetic acid at 100°C for 40 min and then separated on an amino-bonded silica column. One of pentasaccharides thus prepared strongly bound to the EVA-Sepharose column. Structural analysis of this pentasaccharide showed that the Gal1-4GlcNAc1-3(Gal1-4GlcNAc1-6)Gal sugar sequence, which is an l-antigen determinant, was essential for the high affinity binding of the oligosaccharides to the EVA-Sepharose column.Abbreviations EVA Erythrina variegata agglutinin - WGA wheat germ agglutinin - STA potato lectin - LEA tomato lectin - DSA Datura stramonium agglutinin - PBS 0.01 M sodium phosphate buffer, pH 7.3, containing 0.15 M NaCl - Galol galactitol     

Experimentally elevated testosterone increases status signalling in male Greylag geese (<Emphasis Type="Italic">Anser anser</Emphasis>)

Testosterone modulates male vertebrates sexual and social behaviour. We experimentally investigated the testosterone-sensitive behaviours in male greylag geese (Anser anser) by implanting silastic tubes containing crystalline testosterone during the mating season (February; 5 implanted and 5 control males) and in the early winter (November; 7 and 7). Focal animals were part of a semi-tame, unrestrained flock with fully intact social relationships. Excreted testosterone and corticosterone immunoreactive metabolites (TM, BM) were determined by enzyme immunoassay. Individual faecal samples and behavioural protocols were collected daily over a period of 5 weeks, including 1 control week before implantation. In February, no significant behavioural effects of the supplemental testosterone were observed, which may be due to the naturally occurring high systemic androgen levels in spring. In November, however, implanted males had higher TM excretion rates and performed status signalling behaviour (beak up) more frequently than control males. No differences between implanted and control males were found with respect to BM, agonistic interactions or vigilance behaviour. Furthermore, during the second week after implantation, TM positively correlated with the frequency of beak up of implanted males, whilst their female partners were attacked with lower latency by other members of the flock than the females of control males. Hence, status signalling in greylag ganders seems to be testosterone-sensitive year-long and inappropriate status signalling of males may draw attacks towards their females.     

Fractionation of wheat gliadin and glutenin subunits by two-dimensional electrophoresis and the role of group 6 and group 2 chromosomes in gliadin synthesis

Summary Subunits of wheat endosperm proteins have been fractionated by two-dimensional electrophoresis. To determine which subunits in the two-dimensional electrophoretic pattern belong to gliadin or glutenin the endosperm proteins have also been fractionated by a modified Osborne procedure and by gel filtration on Sephadex G-100 and Sepharose CL-4B prior to separation by two-dimensional electrophoresis.The control of production of five major grain protein subunits is shown to be determined by chromosomes 6A, 6B and 6D by comparing two-dimensional electrophoretic protein subunit patterns of aneuploid lines of the variety Chinese Spring. From these and previous studies it is concluded that some , and gliadins (molecular weights by SDS-PAGE 30,000 to 40,000) are specified by genes on the short arms of homoeologous Group 6 chromosomes, the gliadins (molecular weights by SDS-PAGE 50,000 to 70,000) are specified by genes on the short arms of homoeologous Group 1 chromosomes and the glutenin subunits (molecular weights by SDS-PAGE > 85,000) are specified by genes on the long arms of homoeologous Group 1 chromosomes.No major gliadins or glutenin subunits were absent when any of the chromosomes in homoeologous Groups 2, 3, 4, 5 or 7 were deleted. However two gliadins whose presumed structural genes are on chromosome 6D were absent in aneuploid stocks of Chinese Spring carrying two additional doses of chromosome 2A. Two out of thirty-three intervarietal or interspecific chromosome substitution lines examined, involving homoeologous Group 2 chromosomes, lacked the same two gliadins. All the subunits in the other thirty-one chromosome substitution lines were indistinguishable from those in Chinese Spring. It is therefore concluded that the major variation affecting gliadin and glutenins in wheat is concentrated on the chromosomes of homoeologous Groups 1 and 6 but Group 2 chromosomes are candidates for further study.An endosperm protein controlled by chromosome 4D in Chinese Spring is shown to be a high molecular weight globulin.     

Isolation and characterization of β-glucosidases from Aspergillus nidulans mutant USDB 1183

Two extracellular -glucosidases (cellobiase, EC 3.2.1.21), I and II, from Aspergillus nidulans USDB 1183 were purified to homogeneity with molecular weights of 240,000 and 78,000, respectively. Both hydrolysed laminaribiose, -gentiobiose, cellobiose, p-nitrophenyl--L-glucoside, phenyl--L-glucoside, o-nitrophenyl--L-glucoside, salicin and methyl--L-glucoside but not -linked disaccharides. Both were competitively inhibited by glucose and non-competitively (mixed) inhibited by glucono-1,5-lactone. -Glucosidase I was more susceptible to inhibition by Ag⁺ and less inhibited by Fe²⁺ and Fe³⁺ than -glucosidase II.     

Ibf-1 (Iodine binding factor), a highly variable marker system in the Triticeae

Summary Isoelectric focusing of extracts from the endosperm of mature grains of hexaploid wheat and related species was used to study the genetic control of Iodine binding factor (IBF). Ten IBF bands were present in Chinese Spring (CS) and analysis of the nullisomictetrasomic and ditelosomic lines of CS showed nine of them to be controlled by genes on the long arms of the homoeologous group 5 chromosomes. Five alleles were detected at Ibf-A1 locus, four at Ibf-B1 and four at Ibf-D1 among a sample of 46 wheat genotypes. Homoeoloci were found on chromosome 5R of Secale cereale, 5E of Agropyron elongatum, 5U of Aegilops umbellulata, 5Agⁱ of Agropyron intermedium, 5S¹ and 4S¹ of Aegilops sharonensis and 4H of Hordeum vulgare.     

Regeneration of plants from callus and embryos of ‘Royal’ apricot

Immature embryos of apricot (Prunus armeniaca L.) cv. Royal with a PF index of 25–100 were used to regenerate plants in vitro using two methods. In the first case, callus was initiated on MS medium with 4.5 M 2, 4-D plus 0.44 M BA and regeneration of shoots from the callus occurred on MS medium with 4.4 M BA plus 1.0 M 2, 4-D. In the second case, adventitious buds were directly regenerated from the cotyledons on MS medium with 4.4 M BA plus 1.0 M 2, 4-D.Abbreviations BA 6-benzyladenine - IBA dole-3-butyric acid - NAA -naphthylacetic acid - 2, 4-D 2, 4-dichlorophenoxyacetic acid - PF (embryo length/seed length) x 100     

Experimental data on the inheritance of some taxonomic characters inHordeum spontaneum C. Koch emend. Bacht

Summary Hordeum spontaneum C. Koch emend. Bacht. varieties have been both intercrossed and crossed with two cultivated barley varieties ofH. vulgare (L.) emend Vav. et Bacht. with a view of eliciting the nature of inheriting the spikelet-pedicel of the lateral spikelets and the shape of their apex in the said wildgrowing barley. The investigations of F₁ and F₂ showed the inheritance of the spikelet-pedicel to have a dominating nature and to segregate in F₂ in conformity with the Mendelian monohybrid type. In the second case the forms with shorter awn-like formations, or their rudiments, were dominating.As a result ofH. spontaneum x H. vulgare hybridization along with already known forms, new formations were received, they have been conditionally named by the author:sessiliproskowetzii, proskowfertillum, ischnofertillum, and pallipodum.

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Zusammenfassung Im Rahmen größerer Untersuchungen über die Abstammung und Phylogenie der Gerste wurden mehrere Varietäten vonHordeum spontaneum C. Koch emend. Bacht. sowohl untereinander als auch mit zwei Varietäten der Kulturgerste,H. vulgare (L.) emend. Vav. et Bacht., gekreuzt. Es sollte geklärt werden, wie bei den genannten Wildgersten das Stielchen (pedicel) der Seitenährchen sowie die Ausbildung des Apex der Seitenährchen (d. h. ihre Begrannung) vererbt werden. Die Untersuchung der F₁ und F₂ zeigte, daß das Stielchen (gegenüber ungestielten Seitenährchen) dominant und gemäß einer monohybriden Mendelspaltung vererbt wird. Bezüglich der Ausbildung des Apex der Seitenährchen ergab sich im allgemeinen Dominanz der kürzeren oder rudimentären Grannen gegenüber längeren Grannen.Im Ergebnis der Hybridisation zwischenH. spontaneum undH. vulgare wurden, neben bereits bekannten, verschiedene neue Formen gefunden, die vom Autor vorläufig wie folgt benannt werden:sessiliproskowetzii, proskowfertillum, ischnofertillum, pallipodum.Die Ergebnisse werden im Zusammenhang mit Fragen der Abstammung der Kulturgerste diskutiert.

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The cytology of phytophthora infestans

Summary Phytophthora infestans has three kinds of somatic nuclei: an oval shaped nucleus (approx. 3.1×2.7 ) which stains diffusely except for a crescent shaped Feulgen positive cap which stains intensely; a granular nucleus whose contents are organized into a fairly constant number of stained bodies, and, a deeply staining condensed nucleus. The capped nucleus is thought to be metabolic or resting and the granular nucleus is thought to be dividing as it is most commonly found in hyphal tips. Attenuated forms of all three kinds of nuclei are found.Nuclear division is mitotic and intranuclear. Eight—ten chromosomes are seen at metaphase.Sporangia have a mean of 6.3 nuclei which is constant for age and strain of culture. Sporangia become multinucleate as a result of nuclear migration and not by division in the developing sporangium. Zoospores are usually uninucleate.The nuclear cap is persistent throughout nuclear division when it also divides. It is associated with flagella production and nuclear migration and has some of the properties of a blepharoplast.     

Genetic linkage between endosperm storage protein genes on each of the short arms of chromosomes 1A and 1B in wheat

Summary The storage proteins of the endosperm of wheat grain which are known to be controlled by genes on the short arms of the homoeologous group 1 chromosomes are (1) the -gliadins, (2) most of the -gliadins, (3) a few -gliadins and (4) the major lowmolecular-weight subunits of glutenin. Several crosses were made between varieties or genetic lines which had contrasting allelic variants for some of these proteins and which were coded by genes on chromosomes 1A or 1B. The progeny were analysed by one or more of several electrophoretic procedures. The results of all the analyses are consistent with the hypothesis that chromosomes 1A and 1B each contain just one, complex locus, named Gli-A 1 and Gli-B 1 respectively, which contain the genes for the -, - and -gliadins and the low-molecular-weight subunits of glutenin.     

Metabolism of a phenylcoumaran substructure lignin model compound in ligninolytic cultures of Phanerochaete chrysosporium

The degradation of the phenylcoumaran substructure model compound methyl dehydrodiconiferyl alcohol by the white-rot wood decay fungus Phanerochaete chrysosporium was investigated using culture conditions optimized for lignin oxidation. Initial attack was in the cinnamyl alcohol side chain, which was oxidized to a glycerol structure. This was subsequently converted by loss of the two terminal carbon atoms, C and C, to yield a C-aldehyde structure, which was further oxidized to the C-acid compound. The next detected intermediate, a phenylcoumarone, was produced by double bond formation between C and C, and oxidation of the C-alcohol to an aldehyde group. Further oxidation of C to an acid yielded the next intermediate. The final identified degradation product was veratric acid. No products from the 5-substituted aromatic ring, and no phenolic products, were found. The initial glycerol-containing intermediate was a mixture of the threo and erythro forms, and no optical activity could be found, suggesting that its formation might have involved nonstereospecific C-C epoxidation followed by non-enzymatic hydrolysis of the epoxide.Abbreviations TLC thin layer chromatography - LDA lithium diisopropyl amide - DDQ 2,3-dichloro-5,6-dicyanobenzoquinone - MS mass spectrometry - UV ultraviolet spectroscopy     

Interferometeric sensing of β-galactosidase released by recombinant E. coli responding to an endocrine disruptor, tributyltin

A recombinant E. coli ACV1003 releasing -galactosidase by a SOS regulon system when it is exposed to a DNA-damaging compound, has been used to detect endocrine disruptors such as tributyltin (TBT) and triphenyltin (TPT). Maximum response ratio by E. coli ACV 1003 (recA::lacZ) – indicating the maximum ratio of enzyme produced against an environmental toxicant to that produced in the absence of a toxicant – was estimated as 6.3 with 1.0 g TBT ml^–1 at 37 °C, which was considerably higher than those with other strains. Extracellular -galactosidase activity was 51 unit ml^–1, which was 5% of that obtained by the conventional Miller's enzyme assay using solvents. Such a low enzyme activity can be rapidly determined, not by the usual time-consuming and tedious enzyme assay, but by an alternative interferometric biosensor. Heavily-doped porous silicon to apply to an interferometer was fabricated by etching to produce a Fabry–Pérot fringe pattern, which caused the change in the refractive index of the medium including -galactosidase. The change in the effective optical thickness versus -galactosidase activity showed a sigmoid increase up to the concentration of 250 unit -galactosidase ml^–1.     

Uptake and metabolism of benzyladenine during shoot organogenesis in Petunia leaf explants

Benzyladenine (BAP) uptake and metabolism were characterized during the key stages of shoot organogenesis in leaf explants of Petunia MD1. Using leaf explant transfer experiments, it was shown that exposure to 2.2 M BAP for 6, 8 or 10 days induced shoot formation on 27, 80 and 100% of the explants respectively, with a concomitant increase in the number of shoots per explant. BAP uptake and metabolism were characterized in leaf explants after 1, 3, 6 or 10 days exposure to [³H]BAP or 10 days exposure plus an additional 2 days on basal medium (10+2). BAP and 9--D-ribofuranosyl-BAP ([9R]BAP) were detected at days 1 and 3 only. Therefore, the BAP free base was not detectable during the shoot induction period between days 6 and 10, as defined by leaf transfer experiments. The BAP ribotide pool was largest on day 1 and decreased to day 10+2. It is possible that the BAP ribotide pool provided either the active cytokinin itself or acted as a short-term storage form for the active cytokinin in petunia shoot organogenesis. Other metabolites detected in petunia leaf tissue included 7--D-glucopyranosyl-BAP ([7G]BAP), 9--D-glucopyranosyl-BAP ([9G]BAP) and an unidentified metabolite C.Abbreviations BAP benzyladenine - [7G]BAP 7--D-glucopyranosyl-BAP - [9G]BAP 9--D-glucopyranosyl-BAP - [9R]BAP 9--D-ribofuranosyl-BAP - [9R-5P]BAP 5-monophosphate of [9R]BAP - [9R-5PP]BAP 5-diphosphate of [9R]BAP - [9R-5PPP]BAP 5-triphosphate of [9R]BAP - TEA Triethylamine This research was supported in part by NSF Grant DCB-8917378 to J.D.C. and USDA-CRGO Grant 89-37261-4791 to T.J.C.     

Studies on aneuploids of Petunia

Summary The seven possible primary trisomics of Petunia (2 n= 14) located in the progenies of triploid, hypertriploid and hypotriploid plants were distinguished from one another and from diploid on the basis of cytological and morphological criteria. They were provisionally named as Oval, Semi, Slender, Pseudonormal, Arrow, Narrow and Giant. In three of the trisomics, the extra chromosome was identified for the first time at pachytene stage. Postpachytene studies revealed no precise relationship between the length of extra chromosome and the frequency of multiple association.     

Growth,acetylene reduction activity and localization of nitrogenase in relation to vesicle formation in Frankia strains Cc1.17 and Cp1.2

A comparative study was conducted on the effect of NH₄Cl on growth, vesicle formation and formation of nitrogenase of Frankia strains Cc1.17 and Cp1.2, derived from root nodules of Colletia cruciata and Comptonia peregrina, respectively. On a medium without combined nitrogen (P-N), both strains formed spherical cells, called vesicles, like many other Frankia strains. Data are presented on the number of vesicles per mg protein, after cultivation in media with sodium propionate as C-source without combined nitrogen (P-N) or with 0.2 g NH₄Cl/l (P+N). Strain Cp1.2 as may other Frankia strains, showed on P+N medium a very strong reduction of vesicle formation of 99% relative to the number of vesicles formed on P-N medium, after 11 days growth. However, in strain Cc11.17 this reduction was only 70%. The occurence of relatively large numbers of vesicles in P+N media has not yet been reported for other Frankia strains. No acetylene reduction activity was found in NH ₄ ⁺ -grown cells. The regulation of induction of nitrogenase in Frankia by NH₄Cl was tested by immuno-gelectrophoresis using antisera against nitrogenase of Rhizobium leguminosarum PRE. The component I of the enzyme showed crossreactivity while the component II had only a weak crossreaction. The experiments indicated that no nitrogenase was detectable in the NH ₄ ⁺ -grown cells. For the localization of nitrogenase, relative amounts of the enzyme were compared in whole cells and vesicle-enriched fractions. Western blots showed a significant enrichment of nitrogenase in the vesicle fractions, which indicated that most of the nitrogenase was localized in the vesicle.     

Effect of cerulenin on the production of mannosyl-erythritol lipids as biosurfactants by Candida antarctica

Summary The effect of cerulenin, anti-lipogenic antibiotic, on the production and fatty-acid profiles of biosurfactants (mannosyl-erythritol lipids) of Candida antarctica were investigated by changing the chain-length of fatty acid as the carbon source. On longer-chain acid (C₁₄ to C₁₈), the production and fatty-acid profiles of the biosurfactants were not entirely affected by the antibiotic, indicating that the yeast is able to synthesize the biosurfactants from those substrates without the operation of de novo synthesis system of fatty acid. These results thus confirm our previous presumption that a new type of chain-shortening system (partial -oxidation system) mainly contributes to the formation of the extracellular glycolipids as biosurfactants.