The appearance of competence for phytochrome-mediated anthocyanin synthesis in the cotyledons of Sinapis alba L.

Summary It is demonstrated that phytochrome-mediated anthocyanin synthesis in the epidermal cells of mustard seedling cotyledons takes place only 27 h after sowing onwards (at 25°C). This starting point cannot be shifted by light treatments or by nutrients. The late appearance of competence for P _fr (P _r and P _fr, red- and far-red absorbing forms of phytochrome, respectively) with regard to anthocyanin synthesis is not related to the phytochrome system per se (P _rP _fr) as this is fully functional immediately after sowing of the seed; nor is it related to the primary reaction of phytochrome: P _fr+XP _fr XP _fr X (X, X, two forms of a receptor for P _fr) or to the initial action of P _fr X:P _fr X+KY (K, coupling element, leading to the product Y, which is no longer photoreversible). Rather, the starting point is determined by internal factors only and is thus not accessible to any specific control by external factors. On the other hand, however, the beginning of the initial action of P _fr X (coupling point) can be shifted by light via phytochrome under high irradiance conditions. Moreover, it is shown that there is no phytochrome-independent effect of blue light on photomorphogenesis in the young mustard seedling and that there is no rapid dark reversion of P _fr which can be detected by physiological means, at least duringAbbreviations P _r red-absorbing forms of phytochrome - P _fr far-red-absorbing forms of phytochrome - P ₁ total spectrophotometrically detectable phytochrome - HS Hoagland's nutrient solution - HIR high irradiance response     

Genetic variation in the subunits of globulin-1 storage protein of French bean

Summary Charge and molecular weight heterogeneity of globulin-1 (G1) polypeptides of the bean, Phaseolus vulgaris L., were revealed by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Different bean cultivars were classified into three groups: Tendergreen, Sanilac, and Contender on the basis of their protein subunit composition. Nine distinct major bands: 51,49, 48.5,48^T, 48^S, 47, 45.5, 45^S, and 45^C, and two minor bands: 46^T and 46^S were found to account for the three profiles seen on one-dimensional SDS-PAGE. Two-dimensional analysis revealed these eleven protein bands to be composed of a minimum of fourteen distinct protein subunits. The Tendergreen and Sanilac types differ in their G1 polypeptide composition. The protein patterns of the Contender types are intermediate, containing many protein subunits found in the patterns of the Tendergreen and Sanilac types suggesting a genetic and evolutionary relationship.     

Complex sex-determining mechanisms in three species of South American grasshoppers (Orthoptera,Acridoidea)

The karyotype of three species of South American grasshoppers are studied in this paper. Leiotettix sanguineus has two chromosome races, one of them with 2n=23 and an XO sex mechanism and the other, as far as we know limited to the Cerro Chato population, with 2n=22 and an XY sex mechanism. Leiotettix politus has two kinds of individuals, one with 2n=14 and XY sex chromosomes and the other 2n=13 and an X₁X₂Y mechanism. Dichroplus dubius presents 2n=21 and an X₁X₂Y sex chromosomes. One of the three specimens studied shows aberrant behaviour in the meiotic process.     

Silver nitrate and aminoethoxyvinylglycine affect <Emphasis Type="Italic">Agrobacterium</Emphasis>-mediated apple transformation

In Fuji, the production of ethylene was increased with the addition of AgNO₃ and inhibited with the addition of 10 M aminoethoxyvinylglycine (AVG). The addition of 80 M AgNO₃ to transformed explants of Fuji cultured on selection medium resulted in increased ethylene production (20 l l^–1) at 3 weeks. Under examining the effect of AgNO₃ in Fuji, the 40 M AgNO₃ showed with higher 33.8% and 6.5% in the efficiency of regeneration and transformation. However, ethylene production in Gala explants treated with 10M AgNO₃ (3 l l^–1) decreased after 2 weeks compared with the control (5 l l^–1). Although the regeneration efficiency of Gala with 10 M AgNO₃ was higher (41.1%) than the control (20.1%), there was no significant difference in the transformation efficiency at the same concentration. Shoot regeneration of Fuji and Gala was completely inhibited with 10 M AVG. These results suggest that the addition of AgNO₃ affects the efficiency of Agrobacterium-mediated gene transfer in Fuji.Eun Soo Seong, Ill Min Chung- These two Authors Contributed equally to this work     

Molecular switch of F0F1-ATP synthase,G-protein,and other ATP-driven enzymes

Exchange-out of amide tritium from labeled -subunit of ₃₃ complex of F₀F₁-ATP synthase was not accelerated by ATP, suggesting that hemagglutinin-type transition of coiled-coil structure did not occur in -subunit. Local topology of nucleotide binding site and switch II region of G-protein resemble those of F₁- subunit and other proteins which catalyze ATP-triggered reactions. Probably, binding of nucleotide to F₀F₁-ATP synthase induces conformational change of the switch II-like region with transforming subunit structure from open to closed form and this transformation results in loss of hydrogen bonds with the subunit, thus enabling the subunit to move.     

An approach for parameter estimation of biotechnological processes

An approach for parameter estimators design of biotechnological processes (BTP) is presented in case of lack of real time information about state variables. It is based on general reaction rate models and measurements of at least one reaction rate. A general parameter estimator of BTP is designed with the help of which specific rate estimators are synthesized. Stability and convergence of an estimator of specific growth rate for a class of aerobic batch processes are proved. Its effectiveness is illustrated by simulation results. The proposed on-line parameter estimation approach can be used for design of BTP on-line variable estimation algorithms (variable observers of BTP).List of Symbols X, S, P g/l biomass, substrate and product concentrations - C g/l oxygen concentration in the culture broth - C _sg/l saturation concentration of oxygen in the culture broth - C _in, C_outg/l oxygen concentrations in the input air flow and in the outlet gasphase - F _in, F_outl/h the input air flow in the fermenter and output air flow - OUR g/(lh) oxygen consumption rate - OUR _mg/(lh) measured values of OUR - V l volume - , , l/h specific growth, consumption and synthesis rates - K _La(o) l/h specific volumetric mass transfer coefficient - D l/h dilution rate - R _X, R_S, R_Pg/(lh) biomass growth, substrate consumption and product synthesis rates - K _b matrix of yield coefficients - H_b(), H() matrices of known functions of - H(R) matrix of known functions of R - and gain matrices - a vector of the state variables - () a reactions rates vector, describing qualitative relations among the components - R() a reactions rates vector, describing qualitative and quantitative relations among the components - F a feed rates vector - Q a gaseous outflow rates vector - _b () a vector of unknown functions of - ₁() a vector of functions - (t) a vector of unknown time-varying parameters - ₂(, ) an auxiliary vector-function of and - Y _X/S, Y_X/C, Y_X/P substrate, oxygen and product yield coefficients - b maintenence coefficient - k _i(i=1...6) kinetic coefficients - C _i(i=1,2) design parameters estimate     

XXXY sex chromosomes in males of the jumping spider genus Pellenes (Araneae: Salticidae)

Observations of male meiosis and female chromosome number indicate that eight species of Pellenes have the X₁X₂O male, X₁X₁X₂X₂ female sex chromosome system typical of salticids, four species have an X₁X₂X₃Y male, X₁X₁X₂X₃X₃X₃ female system, and one species has both X₁X₂O and X₁X₂X₃Y males. This is the first report of a Y chromosome in spiders. It is hypothesized that the X₁X₂X₂Y system was derived from an X₁X₂O system by a tandem X-autosome fusion which yielded the X₂ and a centric autosome-autosome fusion which yielded the Y. Data on heteropycnosis, chiasmata, segregation, chromosome number and arm length support this hypothesis. The distribution of the X₁X₂X₃Y system within the genus is phylogenetically confusing and suggests that the two sex chromosome systems have been maintained together as a polymorphism in some lineages for long periods of time or that there have been repeated derivations of the X₁X₂X₃Y or X₁X₂O systems.     

Transient state characteristics of adaptation to changes in light conditions for the cyanobacterium Oscillatoria agardhii

Transitions in growth irradiance level from 92 to 7 Em^-2 s^-1 and vice versa caused changes in the pigment contents and photosynthesis of Oscillatoria agardhii. The changes in chlorophyll a and C-phycocyanin contents during the transition from high to low irradiance (HL) were reflected in photosynthetic parameters. In the LH transition light utilization efficiencies of the cells changed faster than pigment contents. This appeared to be related to the lowering of light utilization efficiencies of photosynthesis. As a possible explanation it was hypothesized that excess photosynthate production led to feed back inhibition of photosynthesis. Time-scales of changes in the maximal rate of O₂ evolution were discussed as changes in the number of reaction centers of photosystem II in relation to photosynthetic electron transport. Parameters that were subject to change during irradiance transitions obeyed first order kinetics, but hysteresis occurred when comparing HL with LH transients. Interpretation of first order kinetic analysis was discussed in terms of adaptive response vs changes in growth rate.Non-standard abbreviations Chla chlorophyll a - CPC C-phycocyanin - PS II photosystem II - PS I photosystem I - RC II reaction center of photosystem II - P photosynthetic O₂-evolution - I irradiance, Em^-2 s^-1 - light utilization efficiency of cells, mmol O₂·mg dry wt^-1·h^-1/Em^-2 s^-1 - light utilization efficiency of photosynthetic apparatus, mol O₂·mol Chla ^-1·h^-1/Em^-2 s^-1 - P_max maximal rate of O₂ evolution by cells, mol O₂·mg dry wt^-1·h^-1 - P_max maximal rate of O₂ evolution by photosynthetic apparatus, mol O₂·mol·Chla ^-1·h^-1 - LL low light, E m^-2 s^-1 - HL high light, E m^-2 s^-1 - LH low to high light transition - HL high to low light transition - k specific rate of adaptation, h^-1 - specific growth rate, h^-1 - Q pool size of cell constituent, mol·mg dry wt^-1 - q net synthesis rate of cell constituent, mol·mg dry wt^-1·h^-1     

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

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

Chemical modification of active sites in relation to the catalytic mechanism of F1

Recent studies of chemically modified F₁-ATPases have provided new information that requires a revision of our thinking on their catalytic mechanism. One of the subunits in F₁-ATPase is distinguishable from the other two both structurally and functionally. The catalytic site and regulatory site of the same subunit are probably sufficiently close to each other, and the interaction between the various catalytic and regulatory sites are probably sufficiently strong to raise the uni-site rate of ATP hydrolysis by several orders of magnitude to that of promoted (multi-site) ATP hydrolysis. Although all three subunits in F₁ possess weak uni-site ATPase activity, only one of them () catalyzes promoted ATP hydrolysis. But all three subunits catalyze ATP synthesis driven by the proton flux. Internal rotation of the ₃₃ or ₃ moiety relative to the remainder of the F₀F₁ complex did not occur during oxidative phosphorylation by reconstituted submitochondrial particles.     

Attraction of Aedes aegypti II. Velocity of reaction to host with and without additional carbon dioxide

The velocity with which Aedes aegypti (L.) reacted to odors from a human arm was the same with and without additional carbon dioxide, and was found to increase asymptotically. The derivative dy/dx=–bX_ln described the velocity of response and was not different from the derivatives of the actual data. CO₂ may exert its main effect within the central nervous system.

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Zusammenfassung Die Geschwindigkeit, mit der Aedes aegypti auf den Geruch eines menschlichen Armes reagierte, war mit und ohne Kohlendioxyd-Zusatz die gleiche und nahm asymptotisch zu. Die Ableitung dy/dx=–bX_ln beschreibt die Geschwindigket der Reaktion und weicht von der Ableitung der aktuellen Versuchsdaten nicht ab. CO₂ mag seine Hauptwirkung innerhalb des Zentralnervensystems entfalten.

     

Variability in the 11S globulin fraction of seed storage proteins ofHelianthus (Asteraceae)

The seed storage globulins from sixHelianthus and four hybrids were studied using mono and bidimensional gel SDS electrophoresis (+ 2 mercaptoethanol). The polypeptide composition of each subunit was determined. Different pairs are specifically expressed according to the species studied. Three typical patterns were discriminated. All the studied species exhibit five subunits: two of them are expressed in all the species (₁₁ and ₂₂). The subunit corresponding to the ₁₁ pair is present inH. petiolaris and in the three populations ofH. annuus studied. The _2b2 pair is common toH. annuus andH. argophyllus. H. petiolaris presents two specific _2a2 and ₄₄ pairs andH. annuus a specific ₃₃ pair. InH. argophyllus _{11 33} or ₄₄ are never observed but are replaced by ₁₃ and ₃₁ pairs. Some globulins, poorly represented, are of forms but present chains of higher molecular weights (in the range 54–56 kDa). Expressing variations in the banding patterns between these species by the use of a similarity index reveals complete identity between the three populations ofH. annuus. Identity between the twoH. petiolaris studied is also observed.H. annuus andH. argophyllus appear to be closer to each other thanH. petiolaris concerning the seed storage globulins.     

Oligomerization of uridine phosphorimidazolides on montmorillonite: A model for the prebiotic synthesis of rna on minerals

The 5-phosphorimidazolide of uridine reacts on Na⁺-montmorillonite 22A in aqueous solution to give oligomers as long as 7 mers. The maximum chain length increases to 9 mers and the overall oligomer yield increases when 9:1 ImpU, A⁵ ppA mixtures react under the same conditions. The oligomer yield and maximum chain length decreases with the structure of the added pyrophosphate in the order A⁵ ppA>A⁵ ppU>U⁵ ppU. Structure analysis of individual oligomer fractions was performed by selective enzymatic hydrolyses followed by HPLC analysis of the products. The regioselectivity for 3,5-bond formation is 80–90% in the 9:1 ImpU, A⁵ ppA reaction, a percentage comparable to that observed in the 9:1 ImpA, A⁵ ppA reaction. Oligomerization of ImpU is inhibited by addition of dA⁵ ppdA, and MeppA. No oligomers containing A⁵ ppU were products of the 9:1 ImpU, A⁵ ppA reaction, a finding consistent with the simple addition of the ImpU to the A⁵ ppA and not the rearrangement of an ImpU-A⁵ ppA adduct. Concentrations of lysine or arginine which were close to that of the ImpU did not inhibit oligomer formation. Treatment of Na⁺-montmorillonite with 1 M arginine yielded arginine-montmorillonite, an amino acid-mineral adduct which did not catalyze ImpU oligomerization. Neither the 4–9 mers formed in the 9:1 ImpU, A⁵ ppA reaction nor the 4–9 mers formed by the base hydrolysis of poly(U) served as templates for the formation of oligo(A)s.     

Existe-T-IL des chromosomes sexuels multiples chez le campagnol,Microtus arvalis pallas?

The conclusions ofRaicu, Kirillova & Hamar (1969), according to whichMicrotus arvalis has multiple sex chromosomes (X ₁ X ₂ Y ₁ Y ₂, X ₁ X ₁ X ₂ X ₂), are in contradiction to the earlier work ofRenaud (1938) andMatthey (1953) who have reported heterogamety of the XY, XX type for this species as is the situation in the majority of mammals. The mechanism proposed byRaicu and his coauthors in unknown in mammals where only cases of multiple sex-chromosome mechanisms XY ₁ Y ₂, XX and X ₁ X ₂ Y, X ₁ X ₁ X ₂ X ₂ have been described. It was necessary therefore to reexamine the situation in this vole. The author is of the opinion that the conclusions ofRaicu and his coauthors cannot be substantiated and that in this case we have indeed the common type of sex determination.     

P2Y6 nucleotide receptor activates PKC to protect 1321N1 astrocytoma cells against tumor necrosis factor-induced apoptosis

1. We recently reported that the activation by UDP of rat P2Y₆ nucleotide receptors expressed in 1321N1 astrocytoma cells protected them from TNF-induced apoptosis by suppressing activation of caspase 3 and 8. This study aims to characterize the involvement of intracellular signaling pathways, including kinases, involved in the antiapoptotic effect of UDP.2. Cell death was induced in 1321N1 astrocytoma cells permanently expressing the rat P2Y₆ receptor by exposure to TNF in the presence of cycloheximide. The apoptotic fraction was analyzed using flow cytometry.3. The activation of P2Y₆ receptors by UDP both protected the astrocytes from TNF- induced apoptosis and activated protein kinase C (PKC) isotypes. The phorbol ester PMA also activated PKC and protected the cells from TNF-induced cell death. The - and -isotypes of PKC were both activated in a persistent fashion upon 5-min exposure to either UDP (10 M) or the phorbol ester PMA (100 nM). The PKC isotype was markedly activated upon UDP treatment.4. The addition of PKC inhibitors, GF109203X or Gö6976, partially antagonized the protective effect of UDP and reduced the UDP-induced phosphorylation of extracellular signal-regulated protein kinases (Erk). The inhibitors of Erk, PD98,059 or U0126, antagonized UDP-induced protection.5. The antiapoptotic protein, Akt, was not affected by P2Y₆ receptor activation. Incubation of the astrocytes with calcium modifiers, BAPTA-AM or dantrolene, did not affect the UDP-induced protection from apoptosis.6. The addition of phospholipase C (PLC) inhibitors, D609 or U73122, partially antagonized both UDP-induced protection and PKC activation.7. Therefore, it is suggested that P2Y₆ receptors in 1321N1 cells, through coupling to PC-PLC and PI-PLC, activate PKC to protect against TNF -induced apoptosis, in which the activation of Erk is involved in part.     

Locus-control-region-coupled betaS Antilles- and alpha2-hemoglobin genes select for high alpha2-hemoglobin expression in adult transgenic mice

Two transgenic lines of mice were produced which contained the ^S _Antilles- and ₂-hemoglobin genes trandemly coupled to the micro locus control region (LCR). The LCR^S _Antilles2-hemoglobin transgenic mice expressed high levels of ₂-hemoglobin while ^S _Antilles-hemoglobin expression was virtually undetectable. Abundant ₂-hemoglobin protein was observed in the blood of transgenic mice, while ^S _Antilles-hemoglobin chains could not be detected. Transgenic red blood cells had substantially decreased sensitivity to osmotic lysis. Attempts to produce homozygotes containing the transgene were unsuccessful. The phenotype of these mice closely resembles that of -thalassemic mice. The LCR^S _Antilles2 transgenic mice demonstrate that if the LCR is coupled to the ^S _Antilles- and ₂-hemoglobin genes in tandem, only the distal ₂-hemoglobin gene is selected for expression to significant levels in adult mice. These results support a reciprocally competitive model for LCR-hemoglobin developmental switching.     

Retinoic acid receptor isoform RARγ 1: an antagonist of the transactivation of the RARβ RARE in epithelial cell lines and normal human keratinocytes

The diversity of isoforms of retinoic acid (RA) receptors (RARs) and of DNA sequences of retinoic acid-responsive elements (RAREs) suggests the existence of selectivities in the RAR/RARE recognition or in the subsequent gene modulation. Such selectivities might be particularly important for RAREs involved in positive feedback, eg. the RAR RARE. In the present work we found that in several epithelial cell lines, reporter constructs containing the RAR RARE linked to the HSV-tk promoter were transactivated in the presence of RA by endogenous RARs and co-transfected RAR₁ and RAR₂ isoforms, but not by RAR₁. On the contrary, this latter isoform behaved towards the RAR RARE as an inhibitor of the transactivation produced by endogenous RARs and by cotransfected RAR₁ and RAR₂. RAR₁ also behaved as an antagonist of the transactivation produced by cotransfected RXR. The natural RAR gene promoter or RAR RARE tk constructs were not activated by the endogenous receptors of normal human keratinocytes (NHK), which are known to contain predominantly RAR₁. It was, however, possible to activate to a certain extent RAR RARE-reporter constructs in NHK by co-transfecting RAR₁, RAR₂ or RXR. The antagonist behavior of RAR₁ towards the RAR RARE may explain why in certain cell types such as keratinocytes, RAR is neither expressed nor induced by RA.Abbreviations DMEM Dulbecco's modified Eagle medium - DMSO dimethyl sulfoxide - FCS fetal calf serum - MEM minimal Eagle medium - NHK normal human keratinocyte - RA retinoic acid - RAR retinoic acid receptor - RARE retinoic acid responsive element - TRE thyroid responsive element - VDRE vitamin D response element - RXR retinoid X receptor     

Disruption of a filamentous fungal organism (N. sitophila) using a bead mill of novel design I. General disruption characteristics

The disruption of a typical filamentous fungus, a native strain of Neurospora sitophila, was studied using a glass bead mill of novel design (the Sulzer Annu Mill 01). Cell concentration (in the range of 2.5–5 g dry weight/L) had little influence on the disruption attained. Disruption increased with increasing rotor speed (1000 –4000 r.p.m.) and number of passes (up to six passes) through the Annu Mill. Disruption was observed to follow traditional first-order kinetics for bead mills possessing predominantly plug flow characteristics. It was concluded that in general the Annu Mill would be applicable for the disruption of filamentous organisms.Nomenclature C_P aqueous-phase soluble protein concentration of disrupted sample (g/mL) - CP,MAX aqueous-phase soluble protein concentration of a completely disrupted sample (g/mL) - C_PO aqueous-phase soluble protein concentration of undisrupted sample (g/mL) - N number of passes though the bead mill (–) - R total fraction of cells disrupted (–) Greek Letters _C internal moisture volume fraction of undisrupted cells (–) - _L aqueous phase volume fraction of disrupted cell suspension (–) - _LO aqueous phase volume fraction of undisrupted cell suspension (–) - _L,MAX aqueous phase volume fraction at complete disruption (R=1) (–) - fluid density (kg/m³) - _C density of the microorganism (kg/m³) - _L density of the suspending aqueous phase (kg/m³) - suspension batch residence time in the Annu Mill 01 (min.) Abbreviations DW dry weight     

Structure of F1-ATPases

F₁-ATPases are large multimeric proteins that can be isolated from the membrane bound system that catalyzes the phosphorylation of ADP by inorganic phosphate in bacteria, plants, and mitochondria. They can be visualized in electron micrographs of the inner mitochondrial membranes where they appear as large protruding spheres 90 Å in diameter. The purified F₁-ATPases have a molecular weight of 320,000 to 400,000 daltons and are composed of five non-identical subunits (, , , and ). The stoichiometry of these subunits in the complex is still unknown but compositions of the type ₃₃ and ₂₂₂₂₂ were found to be consistent with some of the available experimental data. This review discusses the recent data and the experimental approaches utilized for the structural characterization of F₁-ATPases.