bluuebunny/crossref_metadata_2025_split huggingface dataset:
Internode length in Pisum. Action of gene lw
Authors: Jolly C. J. , Reid J. B. , Ross J. J. 
Published: February 2008

Jolly, C. J., Reid, J. B. and Ross, J. J. 1987. Internode length in Pisum. Action of gene lw.Mutant K29 of Pisum sativum L. is shown to possess a recessive gene at a new locus, lw, which results in reduced internode length, delayed flowering and increased symptoms of water congestion compared with the parental cv. Torsdag. The interaction of gene lw with the internode length genes na, le, la and cry5 is examined. Extracts from the shoots of Iw plants are shown to contain similar levels of gibberellin (GA)‐like substances to comparable Lw plants, but Iw plants do not elongate to the same extent as Lw plants when treated with GA19 GA19, or GA20. The effect of gene Iw is not graft‐transmissible. Unlike essentially isogenic dwarf lines possessing the GA‐synthesis genes le, Ih or Is, lw plants show a relative increase in elongation similar to Torsdag in response to photoperiod extensions from sources rich in far‐red light. These results suggest that gene lw probably does not reduce elongation by influencing GA‐synthesis and that the response to photoperiod extensions with far‐red light may depend on the level of GA.
γ‐Glutamylcyclotransferase in tobacco suspension cultures: Catalytic properties and subcellular localization
Authors: Steinkamp Reinhard , Schweihofen Barbara , Rennenberg Heinz 
Published: February 2008

Steinkamp, R., Schweihofen, B. and Rennenberg, H. 1987. γ‐Glutamylcyclotransfer‐ase in tobacco suspension cultures: Catalytic properties and subcellular localization.γ‐Glutamylcyclotransferase activity (EC 2.3.2.4) in ammonium sulfate precipitates (40–70% saturation) of extracts from cultured tobacco cells (Nicoliana tabacum L. cv. Samsun) was analyzed as liberation of 5‐oxo‐proline from L‐γ‐glutamyl dipeptides. The enzyme was highly specific for the sulfur containing γ‐glutamyl dipeptides γ‐glutamyl‐L‐methionine and γ‐glutamyl‐i.‐cysteine. Maximum activity was obtained at pH 8.7 and 35°C. As also observed with animal γ‐glutamylcyclotransferase, the tobacco enzyme exhibited a relatively low substrate affinity (γ‐glutamyl‐i.‐methionine: Km 2.2 ± 0.4 mM). In contrast to animal γ‐glutamylcyclotransferase, the tobacco enzyme was not inhibited by the D‐isomerof the substrate D‐γ‐glutamyl‐i.‐methionine; it also did not use the D isomer as a substrate. γ‐Glutamylcyclotransferase of tobacco cells was shown to be a soluble enzyme entirely localized in the cytoplasm.
Ethylene biosynthesis in tissues of young and mature avocado fruits
Authors: Sitrit Yaron , Blumenfeld Amos , Riov Joseph 
Published: February 2008

Sitrit, Y., Blumenfeld, A. and Riov, J. 1987. Ethylene biosynthesis in tissues of young and mature avocado fruits.Avocado (Persea americana Mill.) fruit tissues differ greatly in their capability to pro duce wound ethylene. In fruitlets, the endosperm lacks the ability to produce ethylene because no 1‐aminocyclopropane‐1‐carboxylic acid (ACC) is synthesized and no activity of the ethylene‐forming enzyme (EFE) is present. The cotyledons (embryo) do not produce significant amounts of ethylene at any of the developmental stages of the fruits, although in both young and mature fruits they contain a relatively high level of ACC synthase (EC 4.4.1.‐) activity. Because of the very low EFE activity present in the cotyledons, most of the ACC formed in this tissue is conjugated. Of the various fruitlet tissues, the seed coat has the highest potential to produce ethylene. This is due to a high ACC synthase activity and particularly a high EFE activity. Also, the seed coat is very sensitive to the autocatalytic effect of ethylene. Fruitletpericarp possesses a lower potential to produce ethylene than the seed coat. Towardruit maturiy, the endosperm disappears and the seed coat shrivels and dies so that the pericarp and the cotyledons remain as the only active tissues in the mature fruit. At this stage, the pericarp is the only tissue producing ethylene. Mature precli macteric pericarp has a lower potential to produce ethylene than fruitlet pericarpThe role of ethylene in regulating various physiological processes at different stages of fruit maturation is discussed.
Effects of growth regulators on light‐dependent anthocyanin production in Zea mays seedlings
Authors: Rengel Zdenko , Kordan Herbert A. 
Published: February 2008

Rengel, Z. and Kordan, H. A. 1987. Effects of growth regulators on light‐dependent anthocyanin production in Zea mays seedlings.The effects of ethylene, indolyl‐ and naphthylacetic acids, zeatin, benzyladenine, gib‐berellic acid and triiodobenzoic acid on anthocyanin production in seedlings of Zea mays L. cv. Golden Bantam were investigated. Endogenously produced and exogen‐ously supplied ethylene, as well as the other growth regulators tested markedly suppressed anthocyanin formation. Except for triiodobenzoic acid, the other growth regulators stimulated ethylene production, the amounts produced in the light being larger than those in the dark. Absorption of ethylene by permanganate as well as inhibition of ethylene production or action by Co2+ or Ag+ increased anthocyanin formation in maize seedlings above the level found in the control plants. The inhibiting effect of auxins and cytokinins on anthocyanin production was reversed by Co2+ or Ag+. In contrast, decreased anthocyanin formation caused by gibberellic acid or triiodobenzoic acid seemed unrelated to ethylene and could not be alleviated by Co2+ or Ag+.
Effect of an exogenous auxin on maize tissues. Alteration of protein synthesis and phosphorylation
Authors: Perez L. , Aguilar R. , Sánchez‐de‐Jiménez E. 
Published: February 2008

Pérez, L., Aguilar, R. and Sánchez‐de‐Jiménez, E. 1987. Effect of an exogenous auxin on maize tissues. Alteration of protein synthesis and phosphorylation. ‐ Physiol. Plantarum 69: 517–522.A synthetic auxin 2‐(2‐methyl‐4‐chloro)phenoxypropionic acid (MCPP), analogue of 2,4‐D, alters maize (Zea maysL. H‐30) germination while inducing callus formation. The effect of this auxin on protein synthesis and phosphorylation of the embryonic tissues was explored. Total cytoplasmic proteins were analysed for14C or32P incorporation into trichloroacetic acid precipitable material. MCPP significantly stimulated protein synthesis as well as protein phosphorylation. The protein synthesis pattern was highly altered in the presence of MCPP as analysed by two‐dimensional gel electrophoresis. Analyses by Sephadex G‐100 chromatography and by two‐dimensional gel electrophoresis of phosphorylated proteins indicate that the effect of MCPP on protein phosphorylation was only quantitative.
Free and conjugated gibberellins in dormancy and germination of apple seeds
Authors: Halińska Anna , Lewak St. , Domestica Malus 
Published: February 2008

Halińska, A. and Lewak, St. 1987. Free and conjugated gibberellins in dormancy and germination of apple seeds.The presence of gibberellin A4 (GA4) was confirmed in partly stratified seeds of apple (Malus domestica Borb., cv. Antonówka) by mass spectrometry of the methyl ester. Levels of free and conjugated gibberellins A4+7 and A9 changed during drying of mature seeds, during cold and warm stratification, as well as during germination of dormant and non‐dormant embryos. The temporary rise in GA4+7 during cold stratification and during the culture of dormant embryos as well as the lack of it under conditions of warm stratification, allowed us to postulate a role for GA4+7 in the removal of dormancy. In addition, GA9 was absent in dormant embryos and increased during cold stratification and during the culture of non‐dormant embryos. This suggests the involvement of GA9, in induction of normal development of the seedling. The equivalence between changes in free and conjugated GAs suggests that formation and hydrolysis of conjugates are involved in the control of the physiologically active levels of free GA4+7 and GA9.
Embryonal dormancy in apple seeds is controlled by free and conjugated gibberellin levels in the embryonic axis and cotyledons
Authors: Halinska Anna , Siriska Irena , Lewak St. 
Published: February 2008

Halińska, A., Sińska, I. and Lewak, St. 1987. Embryonal dormancy in apple seeds is controlled by free and conjugated gibberellin levels in the embryonic axis and cotyledons.Free and conjugated gibberellins (GAs) A4+7 and A9 were determined in embryonic axes and in cotyledons of seeds of apple (Malus domestica Borb., cv. Antonó wka) during breaking of dormancy under cold stratification. In both organs, the maximum level of free GA4+7 was found at day 30 of stratification, but the concentration was 700 times higher in axes than in cotyledons. Comparison of changes in free and conjugated GA4+7 levels during stratification allow us to suggest that the accumulation of free hormone in axes is, at the most, to 40% due to release from conjugates already present in the axis; that maximally 20% is derived from hydrolysis of cotyledonary conjugates translocated to axes; and that at least 40% originate from the novo biosynthesis of the hormone. Free and conjugated GA9 levels were similarly altered in axes and in cotyledons, markedly increasing at the end of afterripening. Both release of the free hormone from conjugates and biosynthesis of GA9, appeared to be involved in that increase; no translocation of free or bound GA9, between axes and cotyledons was demonstrated.
Isolation and characterization of an amyloplast envelope‐enriched fraction from immature maize endosperm
Authors: Gardner H. W. , Miernyk J. A. , Christianson D. D. , Khoo U. 
Published: February 2008

Gardner, H. W., Miernyk, J. A., Christianson, D. D. and Khoo, U. 1987. Isolation and characterization of an amyloplast envelope‐enriched fraction from immature maize endosperm.A 10000–100000 g pellet obtained by centrifugation of homogenates from immature (25 days after pollination) de‐embryonated maize (Zea mays L., cv. W64A‐normal and a typical hybrid) kernels was further fractionated by sedimentation on discontinuous sucrose density gradients. Particles with the highest carotenoid content (0.68% by weight carotenoids based upon total lipid) sedimented at densities of 1.083‐1.106 g ml‐1, coincident with the plastid envelope marker enzyme, galacto‐syltransferase (EC 2.4.1.46). Lipids extracted from the carotenoid‐rich fraction were mainly digalactosyldiacylglycerols, monogalactosyldiacylglycerols, phosphatidylcholines, phosphatidylinositols and phosphatidylglycerols, in order of molar abundance. With increasing particle density (>1.106 g ml1) the phospholipid and neutral lipid content increased, and the proportion of carotenoids and galactolipids decreased. Electron micrographs of the carotenoid‐rich fraction revealed vesicles ranging in size from < 0.1 to 0.5 um, as well as smaller granular membranes. The carotenoid‐rich membrane fraction was progressively more difficult to isolate as the endosperm matured, and freezing the immature endosperm prevented subsequent isolation. The lipid and enzyme composition and ultrastructural characteristics of the isolated fraction suggest that it is composed of amyloplast envelope vesicles.
Membrane phospholipid catabolism and Ca2+ activity in control of senescence
Authors: Leshem Ya'acov Y. 
Published: February 2008

Leshem, Y. Y. 1987. Membrane phospholipid catabolism and Ca2+ activity in control of senescence.A key role in the regulation of plant development and senescence appears to be a finely balanced equilibrium between membrane phospholipid catabolism on the one hand, and synthesis and remodelling on the other. In the catabolic “phosphatidyl‐linoleyl(‐enyl) cascade”, entering of Ca2+ into the cytosol triggers the catabolic process by binding to calmodulin and activating phospholipase A2, (EC 3.1.1.4). The latter proceeds to release linoleic or linolenic acid from the sn‐2 (stereospecific numbering) location of intact phospholipid, thus providing substrate for lipoxygenase (EC 1.13.11.12). The action of lipoxygenase then generates a series of oxy‐free radicals, ethylene, endogenous Ca2+ ionophores, malondialdehyde and jasmonic acid. These may recycle to the membrane, causing the entry of more Ca2+ and induction of a further, identical catabolic cycle. With increased cycling, membranes become progressively senescent and undergo biophysical changes altering microviscosity, fluidity, phase configurations of membrane phospholipids and transition temperatures. The cascade does not appear to be specific for the phospholipid substrate, and it is envisaged that besides phospholipase A2, both phospholipase B (EC 3.1.1.5) and lipolytic acylhydrolase could participate in the process.A parallel process counteracting the above, is membrane remodelling and turnover, proceeding initially by the same Ca2+‐ and possibly calmodulin‐triggering, but leading via phospholipase C (EC 3.1.4.10) action and diacylglycerol formation to protein kinase activation and proton pump recharging. It is speculated that auxin and cytoki‐nin, albeit by different pathways, induce this route, for which membrane phospho‐inositides may be the preferred membrane‐associated phospholipid substrate.
Increasing productivity accelerates host–parasite coevolution
Authors: D. C. LOPEZ‐PASCUA L. , BUCKLING A. 
Published: February 2008

AbstractHost–parasite coevolution is believed to influence a range of evolutionary and ecological processes, including population dynamics, evolution of diversity, sexual reproduction and parasite virulence. The impact of coevolution on these processes will depend on its rate, which is likely to be affected by the energy flowing through an ecosystem, or productivity. We addressed how productivity affected rates of coevolution during a coevolutionary arms race between experimental populations of bacteria and their parasitic viruses (phages). As hypothesized, the rate of coevolution between bacterial resistance and phage infectivity increased with increased productivity. This relationship can in part be explained by reduced competitiveness of resistant bacteria in low compared with high productivity environments, leading to weaker selection for resistance in the former. The data further suggest that variation in productivity can generate variation in selection for resistance across landscapes, a result that is crucial to the geographic mosaic theory of coevolution.
Unequal allelic frequencies at the self‐incompatibility locus within local populations of Prunus avium L.: an effect of population structure?
Authors: STOECKEL S. , CASTRIC V. , MARIETTE S. , VEKEMANS X. 
Published: February 2008

AbstractIn this paper, we investigated the genetic structure and distribution of allelic frequencies at the gametophytic self‐incompatibility locus in three populations of Prunus avium L. In line with theoretical predictions under balancing selection, genetic structure at the self‐incompatibility locus was almost three times lower than at seven unlinked microsatellites. Furthermore, we found that S‐allele frequencies in wild cherry populations departed significantly from the expected isoplethic distribution towards which balancing selection is expected to drive allelic frequencies (i.e. identical frequency equal to the inverse of the number of alleles in the population). To assess whether this departure could be caused either by drift alone or by population structure, we used numerical simulations to compare our observations with allelic frequency distributions expected : (1) within a single deme from a subdivided population with various levels of differentiation; and (2) within a finite panmictic population with identical allelic diversity. We also investigated the effects of sample size and degree of population structure on tests of departure from isoplethic equilibrium. Overall, our results showed that the observed allele frequency distributions were consistent with a model of subdivided population with demes linked by moderate migration rate.
Testing Allsop and West’s size at sex change invariant within a fish species: a spurious ratio or a useful group descriptor?
Authors: LINDE M. , PALMER M. 
Published: February 2008

AbstractRecently, it has been suggested that sequential hermaphrodites, from a variety of taxa and a wide range of sizes, change sex at the same relative size. It is said that there exists an invariant (a constant ratio) for such a life trait. However, recent criticisms point out that these results could be a statistical artefact. It has been argued that the wider the range ofx‐axis values (from 2 mm to 1.5 m in the case of sex change), the higher the probability of identifying an invariant by chance. Here, the invariance of the size at sex change ratio is analysed within a single fish species for which the size of sex change varies within a range of only 6.5 cm. Our results support the invariant rule that fishes change sex when reaching 79% of their maximum size.
Pathogenicity of Fusarium verticillioides and Fusarium oxysporum on Pinus nigra seedlings in northwest Spain
Authors: Martín‐Pinto P. , Pajares J. , Díez J. 
Published: February 2008

Summary Fusarium verticillioides may be responsible for causing significant damping‐off damage similar to that incited by F. oxysporum on forest seedlings, resulting in considerable losses in nurseries in northwest of Spain. Traditionally, F. oxysporum has been considered the most important agent of this disease in Spanish forest nurseries. However, recent studies have showed that F. verticillioides also has been frequently isolated from diseased plants. This has increased the necessity for a more comprehensive knowledge of the behaviour and pathogenicity of both Fusarium spp. isolated from these sites. The effect of Fusarium spp. on seed germination and on seedling mortality was analysed by inoculating the fungus at seeding. The in vitro growth of the two species was studied and is discussed in relation to in vivo virulence. Both species caused a reduction in seed germination and an increase in seedling mortality. Mortality caused by F. verticillioides treatments occurred sooner than that for F. oxysporum and the growth rate of F. verticillioides was also greater.
CASA Assessment of Kinematic Parameters of Ram Spermatozoa and their Relationship to Migration Efficiency in Ruminant Cervical Mucus
Authors: Robayo I , Montenegro V , Valdés C , Cox JF 
Published: February 2008

ContentsSperm motility is an indicator of male fertility because of its importance for sperm migration through the female genital tract and for gamete interaction at fertilization. This study analyses the relationship between computer assisted semen analysis (CASA) motility patterns and sperm migration of rams in ruminant cervical mucus. In experiment 1, spermatozoa extended with sperm analysis medium (SAM) and seminal plasma were compared in terms of motility. In experiment 2, 56 semen samples were collected either with artificial vagina (AV) or electroejaculator to be compared in terms of motility performance. In experiment 3, 104 ejaculates collected by AV from 26 males were analysed via the CASA system to characterize their motility patterns. In experiment 4, ejaculates from pairs of rams (20 rams in total) were simultaneously assessed for mucus migration (ovine, caprine, bovine) and motility patterns to evaluate the correlations between both parameters. Semen collected by AV and extended in SAM allows the most reliable assessment for sperm motility. Ram spermatozoa move fast and follow a linear trajectory compared with other ruminants. Continuous line velocity (VCL) and average path velocity (VAP) are the only sperm kinematic parameters that presented significant positive correlations with the ability to migrate in sheep cervical mucus (p < 0.05). Continuous line velocity, VAP, straight line velocity and linearity are highly significantly related with migration efficiency in goat cervical mucus (p < 0.01) and only lateral head displacement is negatively related to sperm migration in bovine cervical mucus (p < 0.05). These results suggest that specific kinematic parameters confer the ability of spermatozoa to colonize and migrate through epithelial mucus with different rheological properties.
Field Trial on Progesterone Cycles, Metabolic Profiles, Body Condition Score and their Relation to Fertility in Estonian Holstein Dairy Cows
Authors: Samarütel J , Ling K , Waldmann A , Jaakson H , Kaart T , Leesmäe A 
Published: February 2008

ContentsResumption of luteal activity postpartum and fertility were investigated in an Estonian Holstein high milk production and good fertility dairy herd. Body condition was scored after every 10 days in 54 multiparous dairy cows (71 lactations) calving inside from December to March during 4‐year period. Blood samples were taken 1–14 days before calving and 1–14, 28–42 and 63–77 days after calving: analytes estimated were serum aspartate aminotransferase (AST), glucose, ketone bodies, total cholesterol, non‐esterified fatty acids and triglycerides. The general linear mixed model was used to compare the data for cows with different characteristics in luteal activity postpartum based on their milk progesterone profiles. Forty‐five per cent of cases had abnormal profiles; delayed resumption of ovarian cyclicity postpartum (DC) was the most prevalent abnormality. There was no difference in body condition scores between the groups. The DC and prolonged luteal phase groups had higher serum AST activity (p < 0.01) 1–14 days postpartum compared with normal group. The DC group also had higher cholesterol and triglyceride values (p < 0.05) 28–42 days postpartum and higher milk fat/protein ratio (p < 0.01) on the first month of lactation compared with normal profile group. Despite long post‐calving anoestrous period (71 ± 5.0 days; mean ± SEM) DC group had 64.7% first service pregnancy rate (normal group 48.6% and PLP group 37.5%). This study did not find any detrimental effect of prolonged anovulatory period postpartum on subsequent fertility.
Luteolytic Effect of Prostaglandin F2α on Bovine Corpus Luteum Depends on Cell Composition and Contact
Authors: Korzekwa AJ , Jaroszewski JJ , Woclawek‐Potocka I , Bah MM , Skarzynski DJ 
Published: February 2008

ContentsProstaglandin F2α (PGF2α) is a main luteolytic factor in vivo; however, its direct luteolytic influence on steroidogenic cells of bovine corpus luteum (CL) is controversial and not fully understood. The aim of the study was to clarify PGF2α action on bovine CL in different in vivo and in vitro conditions and to examine whether the contact among all main types of CL cells is necessary for luteolytic PGF2α action. In experiment 1, the bovine CL (day 15 of the oestrous cycle) was perfused using in vivo microdialysis system with dinoprost (an analogue of PGF2α) for 0.5 h. Dinoprost caused a short‐time increase in progesterone (P4), whose concentration decreased thereafter (at 6‐, 10‐, 12‐ and 24‐h after treatment). In experiment 2, the direct effect of PGF2α on P4 accumulation in CL steroidogenic cells cultured in monolayer (day 15 of the cycle) was determined. PGF2α after 24 h of incubation increased P4 accumulation in steroidogenic CL cells. In experiment 3 steroidogenic, endothelial CL and immune cells (day 15 of the cycle) were incubated with PGF2α in cocultures for 24 h in glass tubes and the levels of P4, stable metabolites of nitric oxide (NO) and leukotriene (LT) C4 were determined. Although PGF2α treatment increased P4 secretion in homogeneous steroidogenic CL cell culture, the decrease in P4 secretion in cocultures of all types of CL cells was observed. The secretion of NO and LTC4 increased after the treatment of PGF2α both in pure cultures of CL cells and in cocultures. The interactions between endothelial and immune cells with steroidogenic CL cells are needed for luteolytic PGF2α action within the bovine CL. Our results indicate that the cell coculture model, including the main types of CL cells, is the most approximate to study PGF2α role in vitro.