Monosomic analysis of heading date and spikelet number in the common wheat (Triticum aestivum L.) multispikelet line ‘Noa’

Summary Genetic analysis of heading date and spikelet number was carried out in the common wheat (Triticum aestivum L.) multispikelet line Noa, by using the monosomic series of the regular line Mara. Noa's high number of spikelets was found to be controlled by a recessive major gene on chromosome 2D; a slight reduction in spikelet number was induced by another recessive gene on Noa's 7A chromosome. Noa's late heading date was found to be controlled by two recessive genes, located on chromosome 2D (a major effect) and 6B (a minor effect). The nature of the genes located on Noa's 2D chromosome and the relationship between spikelet number and heading date are discussed.     

Two novel isoneolacto-undecaglycosylceramides carrying Galα1→3Lewisx on the 6-linked antenna and N-acetylneuraminic acidα2→3 or Galactose α1→3 on the 3-linked antenna, expressed in porcine kidney

Three sialosylated and three neutral glycosphingolipids sharing a common iso-neolacto core were isolated from porcine kidney cortex. They were purified by preparative HPTLC, and were characterized by partial exoglycosidase hydrolysis followed by thin layer chromatography and immunostaining with anti-Gal13Gal, anti-type 2 lactosamine and anti-Lewisx antibodies, methylation analysis, MALDI-TOF mass spectrometry and 1H-NMR spectroscopy. Among neutral glycolipids, one was a known structure, VI3VI3(Gal)2-iso-nLc8Cer, and two were novel structures differing by the number of Gal3Lewisx determinants: VI3VI3(Gal)2V3Fuc-iso-nLc8, and VI3VI3(Gal)2 V3V3(Fuc)2-iso-nLc8. The single Gal3Lewis x determinant was found on the 6-linked antenna. Among sialosylated glycolipids, two had been previously found in other species and tissues, VI3VI3(NeuAc)2-iso-nLc8, and VI3NeuAcVI3Gal-iso-nLc8. A novel structure was discovered presenting a Gal3Lewisx determinant on the 6-linked antenna and a N-acetylneuraminic acid on the 3-linked antenna, VI3NeuAcVI3GalV3Fuc-iso-nLc8. These results indicate that, in vivo, the porcine kidney 3fucosyltransferase synthesizes the Gal3Lewisx determinant, acting on the 6-linked before the 3-linked Gal3neolactosamine, and appears unable to synthesize the sialosylated Lewisx determinant on neolactoseries glycolipids.     

Enzymic synthesis,chemical characterisation and Sda activity of GalNAcß1-4[NeuAcα2-3]Galß1-4GlcNAc and GalNAcß1-4[NeuAcα2-3]Galß1-4Glc

The tetrasaccharides GalNAcß1-4[NeuAc2-3]Galß1-4Glc and GalNAcß1-4[NeuAc2-3]Galß1-4GlcNAc were synthesised by enzymic transfer of GalNAc from UDP-GalNAc to 3-sialyllactose (NeuAc2-3Galß1-4Glc) and 3-sialyl-N-acetyllactosamine (NeuAc2-3Galß1-4GlcNAc). The structures of the products were established by methylation and¹H-500 MHz NMR spectroscopy. In Sd^a serological tests the product formed with 3-sialyl-N-acetyllactosamine was highly active whereas that formed with 3-sialyllactose had only weak activity.     

Action of rat liver Galβ1-4GlcNAc α(2-6)-sialyltransferase on Manβ1-4GlcNAcβ-OMe,GalNAcβ1-4GlcNAcβ-OMe,Glcβ1-4GlcNAcβ-OMe and GlcNAcβ1-4GlcNAcβ-OMe as synthetic substrates

Incubation of synthetic Man\1-4GlcNAc-OMe, GalNAc1-4GlcNAc-OMe, Glc1-4GlcNAc-OMe, and GlcNAc1-4GlcNac-OMe with CMP-Neu5Ac and rat liver Gal1-4GlcNAc (2-6)-sialyltransferase resulted in the formation of Neu5Ac2-6Man1-4GlcNAc-OMe, Neu5Ac2-6GalNAc1-4GlcNAc-OMe, Neu5Ac2-6Glc1-4GlcNAc-OMe and Neu5Ac2-6GlcNAc1-4GlcNAc-OMe, respectively. Under conditions which led to quantitative conversion of Gal1-4GlcNAc-OEt into Neu5Ac2-6Gal1-4GlcNAc-OEt, the aforementioned products were obtained in yields of 4%, 48%, 16% and 8%, respectively. HPLC on Partisil 10 SAX was used to isolate the various sialyltrisaccharides, and identification was carried out using 1- and 2-dimensional 500-MHz¹H-NMR spectroscopy.Abbreviations 2D 2-dimensional - CMP cytidine 5-monophosphate - CMP-Neu5Ac cytidine 5-monophospho--N-acetylneuraminic acid - COSY correlation spectroscopy - DQF double quantum filtered - HOHAHA homonuclear Hartmann-Hahn - MLEV composite pulse devised by M. Levitt - Neu5Ac N-acetylneuraminic acid - Neu5Ac2en 2-deoxy-2,3-didehydro-N-acetylneuraminic acid     

Characterization of the guanosine 3′∶5′-monophosphate-dependent protein kinase from silkworm eggs and analysis of the endogenous protein substrates

Summary In a previous paper, two types of cyclic nucleotide-dependent protein kinases, namely cGMP dependent G-kinase and cAMP dependent A-kinase, in silkworm eggs has been reported (Takahashi et al. 1975; Takahashi 1976). One of these, G-kinase, has now been purified 2400-fold by means of ammonium sulfate fractionation, chromatography on hydroxylapatite, DEAE cellulose, and gel filtration.Some of the properties of the enzyme are described. The enzyme is highly dependent on cGMP; it is strongly inhibited by GTP in a noncompetitive manner not only for ATP but also for cGMP. GTP was found to be highly inhibitory on G-kinases from various tissues of the silkworm, but did not inhibit the A-kinase.Incubation of the egg extract with [-³²P]ATP and Mg²⁺ led to the formation of three major³²P-labelled proteins, with molecular weights of 42.000, 70.000 and 180.000 as analyzed by SDS polyacrylamide gel electrophoresis. Two of them corresponded to the subunits of vitellin.The silkworm vitellin was effectively phosphorylated both by the highly purified G-kinase and by the A-kinase. It is concluded that the G-kinase is involved in the phosphorylation of vitellin in developing silkworm eggs.Abbreviations cAMP adenosine 35-monophosphate - cGMP guanosine 35-monophosphate - A-kinase adenosine 35-monophosphate-dependent protein kinase - G-kinase guanosine 35-monophosphate-dependent protein kinase - MIX 1-methyl-3-isobutylxanthine     

Preleptotene chromosome contraction in Lilium longiflorum “Croft”

A period of chromosome contraction between premeiotic interphase and leptotene was regularly observed in three samples of Lilium longiflorum Croft. Extensive preleptotene chromosome contraction was also observed in L. longiflorum Ace and in the Lilium hybrid Enchantment. Although the stage resembles late mitotic prophase, microsporocytes never develop to metaphase, but despiralize to leptotene, and regular alignment, pairing and chiasma formation follow. As preleptotene chromosome contraction is discovered in an increasing number of organisms it becomes less likely that it represents a true reversion to mitosis. However its absence in many organisms and its extreme variability in others do not support the concept of preleptotene chromosome contraction as a regular meiotic stage. It is suggested that the line of demarcation between mitosis and meiosis is often imprecise, and meiocytes may fluctuate to some extent between these states before a final transition to meiosis is made. The occurrence and extent of this fluctuation may possibly be related to some externally produced substances required for the orderly development of meiotic prophase.     

α°- and β°- Thalassemia in a Thai family: unusually mild homozygous β°-thalassemia without α-globin gene deletion

Summary Alpha-globin genes were analyzed by the direct method of DNA mapping using - and -globin specific probes in a Thai family in which the proposita was an unusually mild °-thalessemia homozygote. °-Thalessemia was found to be segregating in the family, inherited from the proposita's father by one of her younger sisters. However, °-thatlessemia was not detected by this DNA mapping in the proposita. The mild homozygous °-thalessemia in this family may result from interactions of a non-deletion -thalassemia, a gene responsible for high proteolytic activity permitting more balanced globin-chain levels, or from an unusually active hemoglobin F production in the proposita.     

Formation of the imidazolides of dinucleotides under potentially prebiotic conditions

Summary Imidazolides of dinucleotides such as ImpApA can be formed from the corresponding dinucleotides in a two-stage process, which gives up to 15% yields under potentially prebiotic conditions. First a solution of the dinucleotide and sodium trimetaphosphate is dried out at constant temperature and humidity. This produces polyphosphates such as pnApA in excellent yield (80%). The products are dissolved in water, imidazole is added, and the solution is dried out again. This yields the 5-phosphorimidazolides.Abbreviations P₃! trimetaphosphate - A adenosine - U uridine - EDTA ethylenediaminetetraacetic acid - Ap adenosine 2(3)-phosphate - Ap! adenosine cyclic 2:3-phosphate - pA adenosine 5-phosphate - pA²p adenosine 2, 5-diphosphate - pA³p adenosine 3, 5-diphosphate - pAp! 5-phospho-adenosine cyclic 2:3-phosphate - ATP adenosine 5-triphosphate - ImpA adenosine 5-phosphorimidazolide - A²pA adenylyl-[25]-adenosine - A³pA adenylyl-[35]-adenosine - A²pU adenylyl-[25]-uridine - A³pU adenylyl-[35]-uridine - pA²pA 5-phosphoadenylyl-[25]-adenosine - pA³pA 5-phospho-adenylyl-[35]-adenosine - pA²pU 5-phospho-adenylyl-[25]-uridine - pA³pU 5-phospho-adenylyl-[35]-uridine - pApN (N= A, U) 5-phosphate of a dinucleoside phosphate - p_nApN (N = A, U; n = 2, 3, 4.) 5-polyphosphate of a dinucleoside phosphate - ImpA²pA imidazolide of pA²pA - ImpA³pA imidazolide of pA³pA - ImpA²pU imidazolide of pA²pU - ImpA³pU imidazolide of pA³pU - ImpApN imidazolide of pApN     

Hexahydroindanone derivatives of steroids formed by Rhodococcus equi

Summary A mutant strain of Rhodococcus equi accumulates three metabolites from the androst-4-ene-3,17-dione or from its degradation intermediate, 3a-H-4(3'-propionic acid)-7a-methylhexahydro-1,5-indanedione (MEPHIP). These three metabolites are: 3a-H-4a(3'-propionic acid)-5-hydroxy-7a-methylhexahydro-1-indanone--lactone (HIL); 3a-H-4(3'-trans acrylic acid)-5-hydroxy-7a-methylhexahydro-1-indanone (^2'-5-hydroxy-MEPHIP); and 3a-H-4(3'-hydroxy-3'-propionic acid)-5-hydroxy-7a-methylhexahydro-1-indanone (3'-hydroxy-HIL). The behaviour of this mutant allows us to propose a pathway for degradation of the intermediates, methylperhydroindanone propionates. However, during this degradation, the side-chain propionate was eliminated by a-oxidation mechanism. Offprint requests to: A. Miclo     

Mapping the α-globin genes in HB J Mexico carriers

Summary the organization of the -globin genes was studied by restriction endonuclease mapping, in subjects carrying the variant Hb J Mexico. A subject homozygous for Hb J synthesized both Hb J (about 55%) and Hb A and had two loci per chromosome. His restriction site map was found to be identical to that obtained with a normal DNA, except for a mutant Bgl II site which was observed on the Hb J chromosome proximal to the 5-locus. We have also mapped the DNA of a compound heterozygote for Hb J and -thalassemia, who synthesizes 38% Hb J and we have found a single gene corresponding to a –^3.7 haplotype on one chromosome and two genes, respectively ^J and ^A, on the other.     

Demonstration of ‘cardiac-specific’ myosin heavy chain in masticatory muscles of human and rabbit

Summary Human and rabbit masticatory muscles were analyzed immuno-and enzyme-histochemically using antibodies specific to cardiac , slow and fast myosin heavy chain isoforms. In human masseter, temporalis, and lateral pterygoid muscle cardiac myosin heavy chain is found in fibres that contain either fast, or fast and slow myosin heavy chain. In rabbit masseter, temporalis and digastric muscles, fibres are present that express cardiac myosin heavy chain either exclusively, or concomitantly with slow myosin heavy chain or fast myosin heavy chain. Our results demonstrate a much broader distribution of cardiac myosin heavy chain than hitherto recognized and these might explain in part the specific characteristics of masticatory muscles. The cardiac myosin heavy chain is only found in skeletal muscles originating from the cranial part of the embryo (including the heart muscle) suggesting that its expression might be determined by the developmental history of these muscles.     

Effects of clutch size manipulations on reproductive behaviour and nesting success in the cooperatively breeding Bell Miner (Manorina melanophrys)

Summary An experimental manipulation of clutch size was carried out on a wild population of the cooperatively breeding Bell Miner (Manorina melanophrys, Meliphagidae) to assess which factor(s) limit clutch size in this species. Results provide some support for the trade-off hypothesis since there is a cost of reproduction for the breeding female in terms of loss of body mass. The breeding female performs most of the nestling care. Clutches of three eggs are also laid during the mid-breeding season which is the period most favourable for breeding (i.e. nestlings grow faster). This evidence also supports the intrabrood competition hypothesis. Clutches that have lost an egg were more likely to be deserted; this may be an antipredator strategy since partial clutch predation has been recorded in the field. Nest predation was high in this study (64.9%), suggesting that many small clutches may be a strategy to decrease the effect of nest predation on reproductive success over the whole breeding season (nest predation hypothesis). Both the trade-off hypothesis and the nest predation hypothesis may apply in this case since they are not mutually exclusive. The size of the attending group did not greatly affect reproductive success in the short term, although if both age structure and size of the group are taken into account, reproductive success can be better predicted.     

Interaction of alpha-lactalbumin with mini-alphaA-crystallin

A-Crystallin can function like a molecular chaperone. We have recently shown that residues 71-88 in A-crystallin represent the chaperone active site of the protein. A peptide containing the sequence of A-crystallin sequence DFVIFLDVKHFSPEDLTVK (mini A-crystallin) by itself displays the antiaggregation property of A-crystallin. We have prepared a complex of reduced -lactalbumin and mini-A-crystallin and investigated the nature, conformation, and properties of the complex by dynamic light scattering, HPLC analysis, CD spectroscopy, and fluorescence studies. Although mini-A was able to prevent the precipitation of reduced -lactalbumin, large aggregates (50-500 nm) of the complex were formed during the assay. Amino acid composition estimation revealed that -lactalbumin and mini-A-crystallin were present in 1:2 ratio in the aggregates. During our study significant red shift in the Trp fluorescence emission maximum and an increase in Bis-ANS binding to the mini A-crystallin-bound -lacatalbumin were observed. The CD spectra of the complex showed a significant loss of -helical content but the -sheet content appeared to be less affected, indicating the molten-globule state of the reduced lactalbumin in the complex. These data show that the active site of A-crystallin by itself can maintain a significantly denatured and unfolded protein in soluble form.     

Mitogen-activated protein kinases are developmentally regulated during stress-induced microspore embryogenesis in Brassica napus L

Plant mitogen-activated protein kinase (MAPK) cascades are involved in extracellular stress signalling pathways, leading to different cellular responses. Stress-induced microspore embryogenesis involves the internalization of an extracellular stress signal, generating a number of cellular responses where MAPK cascades might be involved. These responses include a change of the developmental programme, the entry into an early proliferative stage and, subsequently, into differentiation stages during haploid embryogenesis. In this work we studied the expression during microspore embryogenesis of several kinases, to assess their putative role in these events. The known Brassica napus MAP kinase kinase kinases (MAP3Ks BnMAP3K1, BnMAP3K1 and BnMAP3K, the BnBSK kinase and B. napus extracellular signal-regulated kinase (ERK) homologues were analysed by electron microscope (EM) in situ hybridization, immuno-gold labelling, immunofluorescence and western blotting. The differential in situ expression of these kinases suggests a role for them during embryogenesis. Two different expression patterns were observed, indicating a different regulation. BnMAP3K1, BnMAP3K, and the ERKs showed a pattern consistent with a role mainly in proliferative events. Conversely, BnMAP3K1 and BnBSK, presented a pattern that suggested an involvement in differentiation stages. In addition, ERK homologues migrate to the nucleus immediately after induction, being found in a phosphorylated state in a larger amount.     

Cytological and molecular observations on Solanum phureja-induced dihaploid potatoes

Summary Seventeen potato dihaploids, produced by pollinating the tetraploid (2n = 48) cv Pentland Crown with pollen from Solanum phureja (2n = 24) dihaploid inducer clones, were studied. Since dihaploids are thought to develop parthenogenetically from unfertilized ovules they were expected to be euploid (2n = 24), but somatic chromosome counts showed that 15 of the 17 dihaploids were aneusomatic. Ten of the clones were predominantly diploid (2n = 24) with a proportion of hyperploid cells that contained 25 or 26 chromosomes. Five of the dihaploids contained variable numbers of triploid cells (2n = 36). RFLP analysis was used to determine whether the additional chromosomes were from S. phureja or S. tuberosum. Unique hybridizing fragments present in S. phureja but not in Pentland Crown were identified. These S. phureja-specific restriction fragments were present in some of the dihaploid offspring of Pentland Crown. Of the 5 clones that contained triploid cells 4 had S. phureja type banding. Four of the 10 aneusomatic clones that contained hyperploid cells had the unique S. phureja hybridizing fragments. We propose that ovules of Pentland Crown were fertilized by pollen from S. phureja and that the aneusomatic clones were derived from triploid zygotes from which some of the S. phureja chromosomes were eliminated. We consider that this is an additional mechanism of dihaploid formation in potato.     

Inhibition by n-3 fatty acids of arachidonic acid metabolism in a primary culture of astroglial cells

Docosahexaenoic acid (226 n-3) was present in low concentrations in a primary culture of rat brain astroglial cells, when compared to brain cortex. We have thus supplemented these cells with this fatty acid and investigated the effects of its incorporation in cell phospholipids on the conversion of arachidonic acid, 204 n-6, through the cyclo and lipoxygenase pathways, after cell stimulation. Docosahexaenoic acid-enriched cells produced less thromboxane B₂ and 6-keto-Prostaglandin F₁ and markedly less 12-hydroxyeicosatetraenoic acid than unsupplemented cells, after stimulation with the Ca²⁺-ionophore A23187. The production of 15-hydroxyeicosatetraenoic acid from arachidonic acid was slightly increased in docosahexaenoic acid-supplemented cells. We have also supplemented these cells with eicosapentaenoic acid (205 n-3) and, in addition to accumulation of this fatty acid in cell phospholipids, we found elevation of 225 n-3 and some increment of 226, confirming that glial cells are able to convert eicosapentaenoic acid to the long chain, more unsaturated derivatives. In conclusion, n-3 fatty acids, when supplemented to glial cells, appear to modulate the arachidonic acid cascade and to be converted through the elongation and desaturation pathways.     

A simple method for maintaining high multiplication of Narcissus shoot cultures in vitro

A simple method for stimulating and maintaining high in vitro multiplication of Narcissus shoot clump cultures was developed. Shoot clumps were subjected either to normal cutting where leaves were trimmed to 20 mm in length at the beginning of each culture passage or to severe cutting where shoot clumps were cut down to the basal plate region removing all green tissue. Severe cutting at the beginning of each culture passage initially doubled the leaf multiplication, compared to normal cutting, but the difference between cutting treatments declined in successive passages. The improvement in leaf multiplication was maintained when shoot clumps were subjected to severe cutting only at every other culture passage, with no cutting in the alternate recovery passages. In vitro multiplication was increased by severe cutting in all seven Narcissus cultivars which were tested.Abbreviations NAA-1 naphthylacetic acid - BAP benzylaminopurine     

The “interval timer”, photoperiod and temperature in the seasonal development of parthenogenetic and sexual morphs in the lime aphid,Eucallipterus tiliae L.

Summary The ability of the lime aphid to produce sexuals (males and females) as an alternative to parthenogenetic females is regulated by a timing mechanism (interval timer) which restrains the appearance of these morphs early in the year. In this species there are two interval timers: one controls the production of sexual females, and the other controls the production of males. Both intervals timers are sensitive to day-length and temperature but they respond in different ways.With the approach of autumn the waning effect of the interval timer inhibiting female production combined with the short day-lengths results in an increasing proportion of the aphids developing into sexual females. The restraining effect of the interval timer results in a gradual transition from parthenogenetic to gamic reproduction over a period of several generations and is still operational in the autumn. However, in this species even relatively long day conditions (17 h) can induce the development of oviparae. This low threshold of response to day-length combined with the short generation time results in the sexual morphs appearing very early in the year. This is of considerable adaptive significance in years when, as frequently happens, the aphids disappear locally before the onset of autumn.     

The effect of monoterpenes on astaxanthin production by a mutant ofPhaffia rhodozyma

Summary The total pigment and astaxanthin content ofPhaffia rhodozyma increased with increasing concentrations -pinene up to 500 l -pinene/l. Above this concentration the total pigment and astaxanthin content as well as the biomass production decreased. The addition of 500 l -pinene/l increased the total pigment content from 1652 g/g to 2201 g/g and the astaxanthin content from 1554 g/g to 1883 g/g. A sharp decrease in maximum specific growth rate occurred above 150 l -pinene/l.     

Glycoconjugates of the Rat Ciliary Body Epithelium: A Lectin Histochemical and Protein Blotting Study

The present study sought to identify and partially characterize the glycoconjugates specific to the double-layered ciliary body epithelium of the rat eye by lectin histochemistry and lectin blottings. Hydrated paraffin sections of Carnoy-fixed Sprague-Dawley rat eyes were stained with a panel of 21 different biotinylated lectins, followed by streptavidin-peroxidase and the glucose oxidase-diaminobenzidine-nickel staining procedure. The results of lectin histochemistry revealed that the inner epithelial layer was rich in GlcNAc(1,4)GlcNAc, -Gal, Gal(1,3)GalNAc, GalNAc(1,3)GalNAc/Gal, GalNAc(1,6)Gal, Fuc(1,2)Gal(1,4)GlcNAc and Gal(1,4)GlcNAc(1,2)Man(1,6) sugar residues as shown by its positive reactivities with S-WGA, PWA, DSA, GS-I-B4, PNA, DBA, SBA, WFA, UEA-I, LTA and PHA-E. The reactivities of GS-I-B4, PNA, DBA and SBA were restricted to the inner layer at the tips of the ciliary processes. On the other hand, the outer epithelial layer was stained evenly by DSA and Jacalin, and partly by MAA, showing that this epithelial layer was rich in GlcNAc(1,4)GlcNAc, Gal(1,3)GalNAc and NeuAc(2,3)Gal disaccharides. These lectin binding patterns of the ciliary body epithelium suggest a topographical and functional difference in this double cell-layered epithelium. Their possible roles in the secretion of aqueous humour and production of ciliary zonule are discussed. Some identified lectin markers specific to these two cell layers may be useful for further experimental studies. Glycoproteins extracted from the dissected ciliary body were separated by SDS-PAGE electrophoresis and analyzed by protein blottings with 8 different lectins. The results showed that at least 10 major membrane-bound glycoproteins, with molecular weights ranging from 30 to 150kD, rich in -GlcNAc, -Gal, /-GalNAc and NeuAc(2,6)Gal residues, were present in the microsomal fraction.