Intraspecific variation for CO2 compensation point and differential growth among variants in a C3−C4 intermediate plant

CO₂ compenstation point (), the concentration of CO₂ at which photosynthesis and respiration are at equilibrium, is a commonly used diagnostic for the C₄ photosynthetic pathway, since it reflects the reduced photorespiration that is a property of C₄ photosynthesis. Geographic variation for was examined within Flaveria linearis, a C₃–C₄ intermediate species. Collections from four widely separated Floridian populations were propagated in a greenhouse and measured for . Little differentiation among populations was found, but significant within-population variation was present. Temperature is a hypothesized selective agent for the C₄ photosynthetic pathway. To test this hypothesis, plants exhibiting a range of were cloned and placed in growth chambers at 25°C and 40°C. After 7 weeks, valves were remeasured and plants were harvested and weighed. There was a poor correlation between initial and final measures of for a given genotype (r=0.38, P>0.1). Broad sense heritability for was computed to be 0.10. At 25°C, there was no relationship between final size and . At 40°C, more C₄-like plants, as indicated by their low , had grown larger. Differences in relative growth rate were attributable more to differences in net assimilation rate than in leaf area ratio. Taken together, these results demonstrate that although significant plasticity exists in the amount of photorespiration in this C₃–C₄ species, high temperature appears to be an effective selective agent for the reduction of photorespiration and the enhancement of C₄-like traits.     

Quantitative measurement of cell-bubble attachment in bubble columns using foam flotation techniques

A simple and convenient system for quantitatively measuring the number of adsorbed animal cells per unit of bubble surface area (, unit: cells/cm2) was developed. The system was successfully applied to recombinant Chinese hamster ovary (r-CHO) suspension cultures to investigate the dynamic cell-bubble attachment in a bubble column. In serum-free medium, values increased with bubble rising height (H) and cell concentration (C) and then became constant (about 1750 cells/cm2) when H and C were sufficiently high. In medium containing protective additives, the trends of values with H were similar to that in serum-free medium. Compared with serum-free medium, polyvinyl-pyrrolidone (PVP) increased the values to 1941 cell/cm2 whereas other tested additives decreased the values of in some different degree.     

The effect of ammonium and nitrate on carbondioxide compensation point and enzymes associated with carbondioxide exchange in wheat

The carbondioxide compensation point (), dry matter production, and the activities of nitrate reductase (NR), glycolate oxidase (GO), ribulose 1,5-bisphosphate carboxylase (RuBPC) and phosphoenolpyruvate carboxylase (PEPC) were measured in wheat, grown on media, containing nitrate or ammonium. Significantly higher and lower dry matter was observed in plants supplied with ammonium-nitrogen (NH₄-N), as compared to those supplied with nitrate-nitrogen (NO₃-N). The activities of NR and PEPC were higher in plants grown on NO₃-N than to those grown on NH₄-N. There were no significant differences in the activities of GO and RuBPC irrespective of whether NO₃-N or NH₄-N was supplied. None of the enzymes was found to be associated directly with the .PEPC activity accounted the measured differences in the and biomass production between NH₄-N and NO₃-N supplied plants. The relationship between PEPC and the is discussed.     

Genetic analysis of resistance to whitebacked planthopper in twenty-one varieties of rice,Oryza sativa L.

Summary The inheritance of resistance to whitebacked planthopper Sogatella furcifera (Horvath) was studied in 21 rice varieties. Reactions of F₁; F₂ and F₃ progenies of the crosses of 21 resistant varieties with the susceptible variety TN 1 revealed that a single dominant gene governs resistance in Mushkan 41, Santhi, Siahnakidar 195, SM2-34, Tirisurkh 251, Zirijowaian 245, 18, 24A, 39, 76 S, 78, 180, 213 B, 267, 293, CI 6037-4, NP97, S39 JKW and Bansphul. In varieties 65 and 274 A, resistance is governed by one dominant and one recessive gene which segregate independently of each other. Tests for allelism with the Wbph 1 gene originally identified in N 22 revealed that the dominant gene present in all the test varieties is the same as Wbph 1. Further studies are required to determine the allelic relationships of the recessive gene found in varieties 65 and 274 A.     

Refinement of the protein backbone angle ψ in NMR structure calculations

Cross-correlated relaxation rates involving the C-H dipolar interaction and the carbonyl (C) chemical shift anisotropy (CSA) have been measured using two complementary 3D experiments. We show that the protein backbone angle can be directly refined against such cross-correlated relaxation rates (^{H C,C}) and the three-bond H/D isotope effect on the C chemical shifts (³C _(ND)). By simultaneously using both experimental parameters as restraints during NMR structure calculations, a unique value for the backbone angle is defined. We have applied the new refinement method to the -Spectrin SH3 domain (a -sheet protein) and to the Sgs1p HRDC domain (an -helical protein) and show that the quality of the NMR structures is substantially improved, judging from the atomic coordinate precision and the Ramachandran map. In addition, the -refined NMR structures of the SH3 domain deviate less from the 1.8 Å crystal structure, suggesting an improved accuracy. The proposed refinement method can be used to significantly improve the quality of NMR structures and will be applicable to larger proteins.     

The effect of fumonisin B1 on developing chick embryos: correlation between de novo sphingolipid biosynthesis and gross morphological changes

Fumonisins, mycotoxins produced byFusarium moniliforme and a number of other fungi, are potent inhibitors of the sphinganine-N-acyltransferase, a key enzyme of sphingolipid biosynthesis, and cause neuronal degeneration, liver and renal toxicity, cancer and other injury to animals.In this study we investigated the effect of fumonisin B₁ on the sphingolipids of developing chick embryos. After yolk sac injection of fumonisin B₁ a concentration and time dependent increase of the sphinganine-over-sphingosine ratio of the embryos could be demonstrated. Studies were done to evaluate the effect of fumonisin B₁ on the glycosphingolipid pattern of the chick embryos. In the presence of 72 µg fumonisin B₁ per egg the incorporation of [¹⁴C]galactose and of [¹⁴C]serine into embryonic glycosphingolipids was reduced by about 70%, although the mass of glycosphingolipids was not affected by the toxin. However, a reduction of the wet weight of the treated embryos was observed. Additionally, histological examinations of whole embryo sections of control and fumonisin B₁ treated embryos are presented. Fumonisin B₁ caused haemorrhages under the skin as well as in the liver of treated embyros. A close correlation between disruption of sphingoid metabolism and light microscopic detectable tissue lesions could be observed.Abbreviations Cer ceramide (N-acylsphingosine) - FB₁ fumonisin B₁ - GM3 NeuAc23Gal14Glc11Cer - GD3 NeuAc28NeuAc23Gal14Glc11Cer - GD1a NeuAc23Gal13GalNAc14(NeuAc23)Gal14Glc11Cer - GT1b NeuAc23Gal13GalNAc14(NeuAc28NeuAc23) Gal14Glc11Cer - HPLC high pressure liquid chromatography - PBS phosphate buffered saline - PDMP 1-phenyl-2-dodecanoylamino-3-morpholino-1-propanol - Sa sphinganine - So sphingosine - Sa/So sphinganine-over-sphingosine - TLC thin layer chromatography - Tris Tris(hydroxymethyl)aminomethan Dedicated to Dr Sen-itiroh Hakomori in celebration of his 65th birthday.     

A linkage map with RFLP and isozyme markers for almond

Inheritance and linkage studies were conducted with seven isozyme genes and 120 RFLPs in the F₁ progeny of a cross between almond cultivars Ferragnes and Tuono. RFLPs were detected using 57 genomic and 43 cDNA almond clones. Eight of the cDNA probes corresponded to known genes (extensin, prunin (2), -tubulin, endopolygalacturonase, oleosin, actin depolymerizing factor and phosphoglyceromutase). Single-copy clones were found more frequently in the cDNA (65%) than in the genomic libraries (26%). Two maps were elaborated, one with the 93 loci heterozygous in Ferragnes and another with the 69 loci heterozygous in Tuono. Thirty-five loci were heterozygous in both parents and were used as bridges between both maps. Most of the segregations (91%) were of the 11 or 1111 types, and data were analyzed as if they derived from two backcross populations. Eight linkage groups covering 393 cM in Ferragnes and 394 in Tuono were found for each map. None of the loci examined in either map was found to be unlinked. Distorted segregation ratios were mainly concentrated in two linkage groups of the Ferragnes map.     

Oligoadenylates formation on an oligouridylate template in the presence of a lead catalyst

Summary Oligouridylates with more than eight chain units can serve as a template for the template-directed condensation of ImpA catalyzed by Pb²⁺ ion. The templates and the Pb²⁺ ion catalyst facilitate the formation of longer oligoadenylates with five or more units. The ratio of 3–5 linked oligomers to the 2–5 isomers increases with increasing chain length of the oligouridylate template. Short oligouridylates up to a hexamer tend to decrease the yield of oligoadenylates, and do not affect the selectivity of internucleotide linkage.Abbreviations EDTA ethylenediaminetetracetic acid - Tris tris(hydroxymethyl)aminomethane - A adenosine - ImpA adenosine 5-phosphorimidazolide - pA adenosine 5-phosphate - Ap adenosine 2(3)-phosphate - poly A polyadenylic acid - AppA P₁,P₂-diadenosine 5-diphosphate - pAp adenosine 2(3),5-diphosphate - ApA adenylyl adenosine - (pA)_n (n = 2,3,) oligomers of pA - ImpApA 5-phosphorimidazolide of ApA - U uridine - pU uridine 5-phosphate - Up uridine 2(3)-phosphate - poly U polyuridylic acid - pUp uridine 2(3),5-diphosphate - (pU)_n (n = 2,3,) oligomers of pU - (pU)_n – (pA)_m cooligomers composed of (pU)_n and (pA)_m units - AppUpUpUpUp pyrophosphate derived from pA and (pU)₄ - AppUp P₁-(adenosine 5)-P₂-(uridine 2(3)-phosphate 5) -pyrophosphate - BAP bacterial alkaline phosphatase - VPD venom phosphodiesterase - N.P₁ nuclease P₁ - RNase A pancreatic ribonuclease - A^* radioactive adenosine     

Green manures of oat,rape and sweet corn for reducing common root rot in pea (Pisum sativum) caused by Aphanomyces euteiches

Green manure crops of sweet corn, soybean, alfalfa, snap bean, rape, pea and of the two oat cultivars Dane and Troy were incorporated into the same soil and containers in which the crop had grown for five weeks. The soil was then evaluated for suppression of common root rot (Aphanomyces euteiches) of pea grown in infested pasteurized and non-pasteurized soils in the greenhouse. Pea biomass reduction and a plant bioassay for A. euteiches were used to measure the green manure suppression of disease. Green manures of sweet corn cv.Jubilee, oat cv.Troy, and rape cv.Humus significantly reduced pea biomass losses over the non-amended control soil treatments. Oat cv.Troyand sweet corn cv.Jubilee green manures significantly reduced inoculum density of A. euteiches over the corresponding fallow controls in inoculated pasteurized soil by 87% and 76%, respectively, and in inoculated non-pasteurized soil by 67% and 66%, respectively. Only the green manure of oat cv. Troy reduced inoculum density significantly below fallow.     

Abnormal hemoglobins in the Silk Road region of China

Summary A review is presented of the occurrence of 24 abnormal hemoglobins (13 -chain variants and 11 -chain variants) in populations in the Silk Road area of Northwestern China. Most frequently occurring were Hb D-Punjab [21(GH4)GluGln] in Uygurs, Kazaks, and Khalkhas, Hb G-Taipei [22(B4)GluGly] in persons of the Han nationality, and Hb G-Coushatta [22 (B4)GluAla] in the Uygurs, Kazaks, Hans, and related nationalities. The data suggest that these variants likely originated in Central Asia, in the Han nationality of China, and in the minorities of northern China, respectively. Other variants occurred at considerably lower frequencies and were imported from other countries or arose as independent mutations. Two variants [Hb Tashikuergan or 19(AB1)AlaGlu; Hb Tianshui or 39(C5) GlnArg] were observed for the first time. The data from this study of the many variants support the movements of various populations in this area, as reported in numerous historical documents.     

Genetic control of heading date and spikelet number in common wheat (T. aestivum L.) line ‘Noa’

Summary The phenology and build-up of spikelet number under 10 h day-length were studied in five wheat lines: the multispikelet line Noa, the regular line Mara, the F₁ hybrid between them and monosomics 2D of Mara and of this hybrid (lacking the 2D chromosome of Mara). Noa had a longer spike development phase, a higher initial number of spikelet primordia and a slower rate of spikelet production than Mara. The F₁ hybrid was similar to Noa in its high initial number of spikelets and to Mara in its high rate of spikelet production. This hybrid had a shorter spikelet phase than both parents. Deletion of one dose of the Mara 2D chromosome from either Mara or the F₁ hybrid caused a reduction in the rate of spikelet production and an increase in the duration of the spikelet phase. These effects were due to the reduced dosage of the 2D chromosome. However, in the F₁ hybrid this deletion also caused an increase in the spike development phase — an indication that Noa carries on its 2D chromosome a recessive gene for late heading date which acts on the spike development phase. This gene of Noa is independent of the day-length sensitive gene ppd, and is different from Noas dominant gene for large initial number of spikelets.     

Genotypic variation in the germination of common bean in response to cold temperature stress

Beans (Phaseolus vulgaris) are regarded as a susceptible crop to suboptimal temperatures. In temperate regions, low temperatures reduce establishment of beans when planted early in the growing season. Seeds of 14 cultivars/lines or beans were germinated in petri dishes at a constant 8, 10, 12, or 18°C or at 12 h alternating temperatures of 10/8, 12/8 or 18/8°C. Differences in germination percentages and rates between cultivars/lines were significant, especially at low temperatures. Cultivars/lines that germinated best and quickly at constant 8°C were Volare, Great Northern (G.N.) Tara, G.N. Belneb # 1, G.N. Spinel, and San Cristobal. Germination percent and rate of Pinto-UI-111 and Canadian Wonder increased significantly when temperatures were increased by 2 to 4°C for 12 h per 24 h, compared with a constant 8°C. Whereas, germination of G.N. Belneb # 1 was reduced. Polyacrylamide gel electrophoresis was used to study the effect of cold treatment on polypeptide patterns of seven cultivars/lines. Seeds were germinated at 18°C constant for 96 h or at 18°C for 48 h followed by 48 h at 2 or 8°C. During cold treatment the synthesis of some polypeptides increased. Volare, G.N. Tara Pinto-UI-111 and Canadian Wonder showed changes in polypeptide patterns, while Alubia-33-1, Michigan 84100 and BAT-1225 showed no changes in polypeptide patterns if compared to the control (96 h at 18°C in the dark). This suggests a likely essential role of these proteins in the development of chilling tolerance.     

Effects of moisture stress on the multiplication and expansion of cells in leaves of sugar beet

Summary Sugar beets were subjected to moisture stress by decreasing the water potential of the culture solution osmotically with polyethylene glycol by a known amount, , and, alternatively by applying matric potential, , at the plant roots. Lowering the water potential at the root surface less than 200 millibars by either method resulted in significant decreases in the rate of cell multiplication. The final number of cells per leaf at = -372 mb the final was 165% of that at = -473 mb ( = –101 mb); similarly at = –15 mb the final cell number was 198% of that at = –196 mb ( = –181 mb). The mean cell volume of leaves was not significantly affected by these levels of moisture stress.     

Temperate and virulent forms of phage theta attacking Bacillus licheniformis

Summary Clear-plaque phage _c, attacking bacitracin-producing strains of B. licheniformis, yields spontaneous temperate mutants at high frequency; the temperate mutants fall into several classes phenotypically different in plaque morphology and properties of lysogenised bacteria. The most common phenotype ₃ has DNA restriction fragment patterns identical with those of the parent _c; some less common temperate forms, i.e. ₁ and ₂, produce different restriction fragment patterns, sugesting that a part of the original _c DNA has been reorganized or replaced by some foreign genetic material. The changed fragment pattern remains stable upon subsequent passaging of the phage or of the lysogenic bacteria. Neither class of temperate phage mutants gives clearplaque revertants at measurable frequency. Lysogenisation of bacteria with any class of temperate phage confers immunity to all temperate forms and to _c; virulent mutants _vir, which plate with 100% efficiency on lysogens for ₁ and ₂ but not for ₃, occur in stocks of _c at a frequency of 10^–7. The mutation from _c to _vir is not accompanied by any change of the restriction fragment patterns of DNA.     

Spectral position control of dye absorption band maximum in an orienting matrix

The continuous control of the maximum position of the dye absorption band (the zero of the derivative dD ()/d of the cell's optical density D ()) in a nematic matrix is demonstrated experimentally, as a result of changing the angle between the optical axis of a planar-oriented sample and the plane of polarization of absorbed light incident normal to the optical axis. The theory proposed describes quantitatively the experimental dependence (). The rotation of the polarizer with given frequency results in the spectral position modulation of the solute band maximum () within (=0°)–(90°)=700 cm^–1.     

The tryptic peptide composition of the beta chains of hemoglobins A and B of the domestic cat (Felis catus)

Summary The tryptic peptides from the ^A and ^B chains of cat hemoglobins A and B have been isolated and the amino acid compositions determined. Differences between the two chains were found in two peptides,T-1 (GlySer) andT-14 (AsnSer and LysArg). The GlySer and LysArg substitutions are placed at-1 and-144 respectively from earlier work, and the third substitution, AsnSer at-139 is suggested from this work. In addition, the presence of a blocked amino terminus in ^B has been confirmed. Tentative sequences constructed by homology with known-chain structures suggest the occurrence of substitutions at _{1 1} contacts in ^A and ^B that may be functionally significant. There are at least 18 differences in amino acid composition between cat ^A and dog-chains and 22 differences between cat ^A and normal adult human-chains.     

β-Amyloid Peptide Binds Equivalently to Binary and Ternary α<Subscript>2</Subscript>-Macroglobulin–protease Complexes

₂-Macroglobulin (₂M) is a protease inhibitor that has separate binding sites for transforming growth factor- (TGF-) and -amyloid peptide (A), both of which have been identified in the ₂M sequence. In the 3D-structure of ₂M, TGF- occupies the ₂M central cavity, overlapping with the space that can accommodate up to two molecules of protease. As a result, ternary ₂M–protease complexes (2 mol protease/mol ₂M) have been reported to not bind TGF-. The goal of the present study was to test whether binding of A to ₂M is controlled by steric constraints imposed by associated proteases, similarly to TGF-. We confirmed that binary ₂M–trypsin complex (1 mol trypsin/mol ₂M) binds increased amounts of TGF-1, compared with native ₂M, while ternary ₂M–trypsin complex binds substantially decreased amounts of TGF-1. By contrast, A-binding to binary and ternary ₂M–trypsin complex was equivalent. In both cases, binding was substantially increased compared with the negligible level observed with native ₂M. Plasmin is a large protease (Mr ~82,000) that substantially occupies the ₂M central cavity; however, ₂M–plasmin complex also bound increased amounts of A, compared with native ₂M. We conclude that A accesses its binding site, in ₂M, from outside the ₂M central cavity. The TGF--and A-binding sites are spatially separated not only in the primary sequence of ₂M, but also in the 3D-structure.     

Conformational transitions in closed circular DNA molecules I. Topological and energetical considerations

A theory of conformational transitions in closed circular DNA as a function of topological linking number of the molecule () is elaborated taking into account topological and energetical considerations. The theory predicts a step-like dependence of a number of superhelical turns in DNA molecules () on . Thus, the number of superhelical turns = for small values of . For a large (when conformational transitions begin to occur) =–_ij, where _ij is the total angle of conformational transitions for a given . This prediction is in good agreement with published data on the dependence of the sedimentation coefficient of circular DNA molecules on their topological linking number. The results also allow to explain the disagreement between a number of titratable superhelical turns in circular DNA molecules and a number of supercoiles seen on electron micrographs for molecules with sufficiently large .     

Fibroblast growth factor increases TNFα-mediated prostaglandin E2 production and TNFα receptor expression in human fibroblasts

To examine the possible role of basic fibroblast growth factor (FGF) in regulating the effects of TNF, we tested the effect of FGF on TNF-mediated PGE₂ production and TNF receptor expression in human fibroblasts. We found that, while FGF alone had no effect on PGE₂ production, it enhanced the amount of PGE₂ produced in response to TNF between 3 and 11-fold. FGF stimulated TNF-induced PGE₂ production independent of potential TNF-mediated IL-1 production, as neither anti-IL-1 mAbs nor IL-1 receptor antagonist protein (IRAP) inhibited TNF induced-PGE₂ production or the stimulatory effect of FGF. A one minute exposure of cells to FGF prior to removal was sufficient to significantly enhance TNF-induced PGE₂ production; the maximal FGF effect was reached after a 6 h preincubation. We also found that FGF significantly enhanced TNF receptor expression. Untreated fibroblasts expressed 3,900 receptors/cell, while cells treated with FGF for 6h expressed 9,500 receptors/cell, a 2.4-fold increase in receptor number; there was no apparent change in affinity for TNF (K_d 3.8×10^–11 M). The FGF-mediated increase in TNF receptor expression and TNF-mediated PGE₂ production could be abolished by FGF mAbs, indicating a specific FGF effect. These results show that FGF increases TNF receptor expression and suggest that this may account, at least in part, for the ability of FGF to enhance TNF-mediated PGE₂ production in human fibroblasts.     

Ganglioside-cholera toxin interactions: a binding and lipid monolayer study

Summary On t.l.c. plates ¹²⁵I-cholera toxin binds to a disialoganglioside tentatively identified as GD_lb with about 10 times less capacity than to ganglioside GM₁. Binding of labeled toxin to both gangliosides was abolished in presence of excess amounts of unlabeled B subunit. Ganglioside extracts from human or pig intestinal mucosa showed toxin binding to gangliosides GM₁ and GD_1b. In ganglioside-containing lipid monolayers the penetration of the toxin was independent of the ganglioside binding capacity.Abbreviations GM₂ Gal-NAc14Gal(3-2NeuAc)14G1c1Cer - GM₁ Gal3Ga1-NAc14Gal(32NeuAc)14G1c11Cer - GD_1a NeuAc23Ga113Gal-NAc14Gal(32NeuAc)14G1c11Cer - GD1b Gall3Gal-NAcl4Gal(32NeuAc82NeuAc)14Glc11Cer - GT_1b NeuAc23Ga113Ga1-NAcal4Gal(3-2NeuAc82NeuAc)14G1c11Cer - dpPC 1,2-hexadecanoyl-sn-glycero-3-phosphocholine - dpPE 1,2-hexadecanoyl-sn-glycero-3-phosphoethanolamine