Mechanisms of reproductive isolation of interspecific hybridization between Trillium camschatcense and T. tschonoskii (Melanthiaceae)

Reproductive isolation plays a significant role in the prevention of gene flow between different plant species. Isolation factors can vary, acting either pre‐ or postzygotically. Trillium camschatcense and T. tschonoskii are herbaceous perennials which frequently grow together in Hokkaido, Japan. Natural hybrid formation, T. × hagae, between these species is common, and occurs asymmetrically with T. camschatcense as the maternal parent and T. tschonoskii as the paternal. Here, we examined the efficiency of each reproductive isolation factor to clarify which factor was responsible for the frequency and asymmetry of the hybridization. We found that prezygotic barriers, self fertilization and conspecific pollen precedence, are major isolation factors in both parental species, and that T. tschonoskii as a maternal parent has more effective prezygotic barriers than T. camschatcense. In addition, hybrids with T. tschonoskii as the maternal parent were not observed to reach the flowering stage. We concluded that prezygotic isolation factors in the both species act as main barriers to prevent natural hybridization, and that asymmetry of the isolating barriers between these species would promote T. camschatcense as the maternal parent of the hybrids.     

A reconsideration of relationships among Japanese Trillium species based on karyology and AFLP data

To reexamine the relationships among the Japanese Trillium species that form a polyploid series, we performed principal-coordinates analysis (PCOA) based on proposed karyotypic compositions and on amplified fragment length polymorphism (AFLP) analysis. A hexaploid species, T. smallii, whose karyotypic composition had been hypothesized as K₂K₂SSUU, with hybridization between tetraploid T. apetalon (SSUU) and a presumed K₂K₂ diploid species, showed a genotype corresponding to T. yezoense (K₁SU). Accordingly, T. smallii appears to be an allopolyploid of T. yezoense, with the karyotypic composition K₁K₁SSUU. Trillium channellii, a recently described tetraploid species whose origin and genealogical position remains unclear, showed a genotype corresponding to K₁K₁K₂T. We conclude that T. channellii may be derived from hybridization of T. camschatcense (K₁K₁) as the seed parent and T. tschonoskii (K₂K₂TT) or hexaploid T. hagae (K₁K₁K₂K₂TT) as the pollen parent.     

Chromosome maps of trilliaceae: II. A study of the genome composition in polyploid species of the genus Trillium by fluorescence nucleotide base-specific staining of heterochromatic chromosome regions

Chromosome banding with nucleotide base-specific fluorochromes chromomycin A3 (CMA) and Hoechst 33258 (H33258) was used to study the karyotypes and to construct cytological maps for diploid Trillium camschatcense (2n = 10), tetraploid T. tschonoskii (2n = 20), hexaploid T. rhombifolium (2n = 30), and a triploid T. camschatcense x T. tschonoskii hybrid (T. x hagae, 2n = 15). With H33258, species- and genome-specific patterns with numerous AT-rich heterochromatin bands were obtained for each of the four forms; CMA revealed a few small, mostly telomeric GC-rich bands. In T. tschonoskii, the two subgenomes were similar to each other and differed from the T. camschatcense genome; on this evidence, the species was considered to be a segmental allotetraploid. In T. x hagae, one T. camschatcense and both T. tschonoskii subgenomes were identified. The subgenomes of T. rhombifolium only partly corresponded to the T. camschatcense and T. tschonoskii genomes, in contrast to the morphologically identical Japanese species T. hagae. This was assumed to indicate that allohexaploids T. rhombifolium and T. hagae originated independently at different times; i.e., their origin is polyphyletic. Based on the chromosome maps, a new nomenclature was proposed for the Trillium genomes examined: K1K1 for T. camschatcense, T1T1T2T2 for T. tschonoskii, T1T1T2T2 for T. x hagae, and K1RK1RT1RT1RT2RT2R for T. rhombifolium.     

Experimental analyses of the evolutionary processes inTrillium

In the Japanese species ofTrillium examined here, every interspecific cross produced healthy F₁ progeny at the rate of about 50 to 60 per cent of the total inborn ovules except forT. hagae. These figures were not appreciably different from those of self-pollinated or sib-mated examples of these species.Trillium hagae, a putative natural hybrid betweenT. kamtschaticum (2n=10) andT. tschonoskii (2n=20), accepted all foreign sources of pollen grains in manual pollination. These and other crossing experiments suggest that no appreciable barrier has developed that might cause interspecific crossability and that they are habitual inbreeders. Despite theri crossability, a very low rate of actual pollen flow was detected by examining electrophoretic phenotypes of seeds taken from sympatric populations of these species.     

Analysis of teleost hemoglobin by Adair and Monod-Wyman-Changeux models

Summary The allosteric effects of the erythrocytic nucleoside triphosphates (NTP) and of proton concentrations were investigated by precise measurement of Hb–O₂ equilibria of tench hemoglobin (including extreme, high and low saturation ranges) and analysed in terms of the MWC two state model and the Adair four step oxygenation theory.At low concentrations (NTP/Hb ratio=1.0, and pH>7.3) ATP, GTP and protons decrease Hb–O₂ affinity by increasing the allosteric constantL and reducingK _T, the association constant¹ of the deoxy, tense state of the Hb, without significantly affecting that (K _R) of the oxy state, increasing the free energy of cooperativity (G). High concentrations of these effectors, however, also reduceK _R. The greater sensitivity of the half-saturation O₂ tension (P ₅₀) of the Hb to GTP than to ATP at the same concentration, correlates with greater effects of GTP on bothK _T andK _R. The pH and NTP dependence of the four Adair association constants and the calculated fractional populations of Hb molecules in different stages of oxygenation show that the autochthonous NTP effectors and protons stabilize the T structure and postpone the TR transition basic to cooperativity in fish Hb.The possible implications of the findings for aquatic respiration are discussed.Abbreviations ATP adenosine triphosphate - DPG 2,3-diphosphoglycerate (glycerate-2,3-bisphosphate) - GTP guanosine triphosphate - IHP inositol hexaphosphate - NTP nucleoside triphosphates In this paperK _T andK _R are defined as theassociation equilibrium constants instead of dissociation constants (as originally defined by Monod et al. 1965) to facilitate comparison with the Adair constants     

Chromosome numerical mosaicism in some hybrids of theSolanum nigrum complex

The colchicine amphiploid (2n=72) of the hybridSolanum nodiflorum (2n=24)×S. villosum (2n=48) was crossed toS. memphiticum (2n=72) and toS. nigrum (2n=72). In the resulting F₁ hybrids chromosome numerical mosaicism was observed in the anthers of some plants. It was found that chromosome mosaicism did not affect chromosome pairing in normal cells. Disharmonious gene combination seems to be responsible for premeiotic somatic instability which results in chromosome mosaicism observed during meiosis in pollen mother cells. Gene or genes for fertility are transmitted independent of those for chromosome stability. It is suggested thatS. nigrum andS. memphiticum possess in common a gene complex, which when combined withS. nodiflorum andS. villosum genomes will induce somatic instability.     

Oxygen equilibria of cathodic eel hemoglobin analysed in terms of the MWC model and Adair's successive oxygenation theory

Allosteric effects of erythrocytic NTP and proton concentrations on cathodic eel Hb were investigated by precise measurement of Hb-O₂ equilibria (including extreme saturation values) and analysis in terms of the MWC two-state model and the Adair four-step oxygenation theory. Stripped cathodic Hb shows a reverse Bohr effect and high sensitivities to ATP and GTP that extend to high pH values (>8.5). A decrease in pH raises K _T and lowers the allosteric constant L; compared to opposite effects in normal Bohr effect Hbs. Phosphates even at low concentrations (GTP/Hb=0.5) annihilate the reverse Bohr effect. GTP exerts a reater effect than ATP due to greater changes in K _T and L, and NTP slightly reduces K _R. In the absence of NTP, about 1.1 protons are released on deoxygenation at pH 8.15 (where most protons are released), indicating a pK value of the reverse Bohr group of approximately 8.2 (higher in oxy-Hb and lower in deoxy-Hb). The pH and NTP dependence of the Adair association constants and calculated fractional populations of Hb molecules in different oxygenation stages show that NTP effectors stabilise the T structure and postpone the T-R transition, whereas protons in the absence of NTP have the opposite effect. A molecular mechanism for the reverse Bohr effect is suggested.Abbreviations DPG 2,3 diphosphoglycerate - EPLC fast protein liquid chromatography - Hb hemoglobin - HEPES N-2-hydroxymethyl-piperazine-N-2-ethanesulfonic acid - K _T and K _R O₂ association equilibrium constants of Hb in the deoxy- and oxy-states, respectively - k ₁, k ₂, k ₃ and k ₄ Adair affinity constants for binding of the four O₂ molecules to Hb - L allosteric constant - NTP nucleoside triphosphate - P _m medium O₂ pressure - n ₅₀ Hill's cooperativity coefficient at P ₅₀ - P ₅₀ half-satutarion O₂ tension - TRIS tris(hydroxymethyl)aminomethane     

Chromosome banding in the genusPinus

Somatic chromosomes (2n=24) ofPinus luchuensis Mayr at metaphase were observed by fluorescent banding methods with chromomycin A₃ (CMA) and DAPI. CMA-bands appeared at the interstitial and/or proximal regions of nearly all chromosomes. DAPI-bands appeared at the interstitial and/or centromeric regions of nearly all chromosomes, and pairs of DAPI-dots appeared at the centromeric regions. Each homologous pair of chromosomes in the chromosome complement was identified by the CMA and DAPI fluorescent banding patterns. The interstitial CMA-bands were mostly localized at the secondary constrictions of the Feulgen-stained chromosomes. The fluorescent banding pattern ofP. luchuensis was very similar to that ofP. thunbergii, but was different from that ofP. densiflora.     

Increased insulin receptor binding in erythrocytes from growth hormone-deficient children

Erythrocytes from growth hormone-deficient children (GHd-children) (n=10) showed a statistically significant increase in insulin binding at low unlabeled insulin concentrations, together with a threefold decrease in apparent receptor affinity, as compared to control children (C) (n=11). Scatchard analysis of the binding data using the two-site model revealed that both the receptor concentration R₁ [GHd-children 0.10±0.01 ng/ml and C 0.03±0.002 ng/ml] and the dissociation constant K_D1 [GHd-children (0.48±0.05)×10^–9M and C (0.19±0.01)×10^–9M] for high affinitylow capacity sites were significantly increased in erythrocytes from GHd-children, while neither receptor concentrations (R₂) nor the dissociation constant (K_D2) for low affinity-high capacity sites proved to be altered. These events were accompanied by a normal sensitivity to insulin as well as glucose tolerance in the GHd-group. The meaning of the increased insulin binding with normal insulin sensitivity in GH-deficiency is discussed.     

NMR relaxation study of water protons in Syrian hamster fetal cells at 300 MHz

TheT ₁ andT ₂ relaxation times of water protons in two cell types in culture derived from Syrian hamster fetuses (normal primary or secondary fetal cells vs BP6T tumor cells derived from the normal cells transformed by carcinogens) were measured at 7.05 Tesla magnetic field (proton frequency =300 MHz). TheT ₁/T ₂ ratios and the correlation time, τ _c , calculated from theT ₁/T ₂ ratio of cellular water protons, are significantly different in these two fibroblastic cell types of the same biological origin and with similar morphologies and growth rates in culture.     

The effect of solvent viscosity and temperature on DNA viscoelastic behavior

The effect of solvent viscosity (η_s) and temperature (T) on the shape of the concentration dependence of the principal and total recoils in creep-recovery viscoelastometry experiments has been studied for T4 DNA solutions. The range of DNA concentration (c) was 2 – 40 μg/ml; glycerol, 70–80% v/v, sucrose, 60% v/v; NaCl, 5 mM – 1M; and T, 275 – 323 K. A linear proportionality between recoil and c was obtained at high η_s/T. At low η_s/T, the c-dependence was nonlinear, approaching saturation at higher c. At low c, the slope of both curves was the same. Transition between “linear” and “nonlinear” values occurred over a narrow range of η_s/T (a width of 1–5 K if η_s/T was changed by varying T). (η_s/T)_tr, the midpoint of the transition, was independent of solvent properties other than viscosity. Also, (η_s/T)_tr increased with c. For a given c, η_s/T values above this transitional value yield linear behavior; below this, nonlinear behavior. The ratio of linear to nonlinear recoil values is a linear function of c with K_c, the slope of this dependence, independent of η_s and T. A kinetic model for the observed nonlinearity of recoil with c is presented. It explains the independence of K_c on η_s and T. An attempt has been made to explain the linear–nonlinear transitions by comparison of τ₁ and T_R, the lifetime of the contact points of the polymer network in the de Gennes theory. The nonlinear values are consistent with a pseudogel that exists when τ₁ < T_R. At τ₁ > T_R, the DNA behavior is similar to that in dilute solutions (linear values). Thus, the condition for transition is τ₁ = T_R. However, some unsolved problems remain.     

Inflammation Correlates With Markers of T‐Cell Subsets Including Regulatory T Cells in Adipose Tissue From Obese Patients

Accumulation of cytotoxic and T‐helper (T_h)1 cells together with a loss of regulatory T cells in gonadal adipose tissue was recently shown to contribute to obesity‐induced adipose tissue inflammation and insulin resistance in mice. Human data on T‐cell populations in obese adipose tissue and their potential functional relevance are very limited. We aimed to investigate abundance and proportion of T‐lymphocyte sub‐populations in human adipose tissue in obesity and potential correlations with anthropometric data, insulin resistance, and systemic and adipose tissue inflammation. Therefore, we analyzed expression of marker genes specific for pan‐T cells and T‐cell subsets in visceral and subcutaneous adipose tissue from highly obese patients (BMI >40 kg/m², n = 20) and lean to overweight control subjects matched for age and sex (BMI <30 kg/m²; n = 20). All T‐cell markers were significantly upregulated in obese adipose tissue and correlated with adipose tissue inflammation. Proportions of cytotoxic T cells and T_h1 cells were unchanged, whereas those of regulatory T cells and T_h2 were increased in visceral adipose tissue from obese compared to control subjects. Systemic and adipose tissue inflammation positively correlated with the visceral adipose abundance of cytotoxic T cells and T_h1 cells but also regulatory T cells within the obese group. Therefore, this study confirms a potential role of T cells in human obesity‐driven inflammation but does not support a loss of protective regulatory T cells to contribute to adipose tissue inflammation in obese patients as suggested by recent animal studies.     

X-ray crystal structures of the copper(II), nickel(II) and silver(I) complexes of a 17-membered dibenzo macrocycle with a N3S2 donor set

The copper(II), nickel(II) and silver(I) complexes of the pentadentate 17-membered macrocycle 1, 12, 15-triaza-3, 4:9, 10-dibenzo-5,8-dithiacycloheptadecane (L¹) have been prepared as perchlorates and characterized by X-ray crystallography. The N₃S₂ ligand uses all donor atoms for complexation. The copper coordination is square pyramidal with one sulfur atom in the axial site. Ni(II) displays an octahedral coordination by an interaction with a water molecule. The Ag(I) coordination is best described as a distorted pentagonal bipyramid. In [CuL¹]²⁺ the 1, 4, 7-triazaheptane fragment of L¹ is meridionally coordinated, but facially in [NiL¹(H₂O)]²⁺ and intermediate in [AgL¹](ClO₄). Crystal data for [CuL¹](ClO₄)₂: monoclinic, space group P2₁/n, a = 13.153(8), b = 11.951(5), c = 17.880(8)Å, β = 110.29(4)°, Z = 4, R = 0.086 for 2732 independent reflections with I 2σ(I); [NiL¹(H₂O)](ClO₄)₂: monoclinic, P2₁/a, a = 10.771(2), b= 16.157(2), c = 15.286(2) Å, β =93.08(1)°, Z = 4, R = 0.085 for 1464 independent reflections with I 2σ(I); [AgL¹](ClO₄): monoclinic, P2₁/n, a = 12.708(9), b = 9.483(7), c = 19.569(13) Å, β= 103.95(6)°, Z = 4, R = 0.039 for 3600 independent reflections with I 2σ(I).     

Light scattering and viscosity study of heat aggregation of insulin

Aggregation behavior and hydrodynamic parameters of insulin have been determined from static and dynamic light scattering experiments and intrinsic viscosity measurements carried out at pH 4.0, 7.5, and 9.0 in the temperature range 20–40°C in aqueous solutions. The protein aggregated extensively at elevated temperatures in the acidic solutions. Intermolecular interactions were found to be attractive and to increase with temperature. The measured intrinsic viscosity [η], diffusion coefficient D₀, molecular weight M, and radius of gyration R_g exhibited the universal behavior: M[η] = (2.4 ± 02) × 10⁻²⁷ (R_e,η/R_e,D)³(D_0η/T)⁻³ and (D₀√n)₋₁ ≃ (√6 πη₀ζβ/k_BT) [1 + 0.201)(v/β³)√n], where n is the number of segments in the polypeptide. The effective hydrodynamic radii deduced from [η], (R_e, η) and the same deduced from D₀, (R_e,D) showed a constant ratio, (R_e,η/R_e,D = 1.1 ± 0.1). R_e,D/R_g = ξ was found to be (0.76 ± 0.07). From the known solvent viscosity η₀, the segment length β was deduced to be (10 ± 1) Å. The excluded volume was deduced to be (5 Å)³ regardless of pH. The Flory-Huggins interaction parameter was found to be χ = 0.45 ± 0.04, independent of pH and temperature. © 1998 John Wiley & Sons, Inc. Biopoly 45: 1–8, 1998     

Intracellular activity of morphologically identified neurons of the grass frog's optic tectum in response to moving configurational visual stimuli

Summary In the grass frogRana temporaria, various classes of tectal neurons were identified by means of intracellular recording and iontophoretic staining using potassium-citrate/Co³⁺-lysine-filled micropipettes, which have been defined previously by extracellular recording methods. Class T5(1) neurons had receptive fields (RF) of 33°±5° diameter. In response to a moving 8°×8° square (S), a 2°×16° worm-like (W), or a 16°×2° antiworm-like (A) moving stripe, these cells showed excitatory postsynaptic potentials (EPSPs) and spikes which were interrupted occasionally by small inhibitory postsynaptic potentials (IPSPs). The excitatory responses (R) were strongest towards the square (R_S) and less to the worm (R_W). For the antiworm (R_A) the responses were smallest or equal to the worm stimulus yielding the relationship R_S>R_WR_A. Some of these cells were identified as pear-shaped or large ganglionic neurons, whose somata were located in the tectal cell layer 8. The somata of other large ganglionic neurons were found in layer 7 and the somata of other pear-shaped neurons at the top of layer 6, both displaying T5(1) properties. Class T5(2) neurons (RF=34°±3°) responded with large EPSPs and spikes, often interrupted by small IPSPs, when their RF was traversed by the square stimulus. The excitatory activity was somewhat less to the worm stimulus, whereas no activity at all, or only IPSPs, were recorded in response to the antiworm-stimulus; thus yielding the relationship for the excitatory activity R_S>R_W>R_A 0. Such a cell was identified as pyramidal neuron; the soma was located at the top of layer 6, with the long axon travelling into layer 7 to the medulla oblongata. Class T5(3) neurons (RF=29°±6°) showing EPSPs and spikes according to the relationship R_S>R_A>R_W have been identified as large ganglionic neurons. Their somata were located in layer 8. Class T5(4) neurons (RF=24±7°) responded only to the square stimulus with EPSPs and spikes, sometimes interrupted by IPSPs and yielding the relationship R_S>R_AR_W0. The somata of these large ganglionic or pear-shaped neurons were located in layer 8. Class T1(1) neurons (RF=30°–40°) were most responsive to stimuli moving at a relatively long distance in the binocular visual field, and have been identified as pear-shaped neurons. Their somata were located in layer 6.Further neurons are described and morphologically identified which have not yet been classified by extracellular recording methods. For example,IPSP neurons (RF=20°–30°) responded (R) with IPSPs only according to the relationship R_S>R_A R_W. The somata of these pear-shaped neurons were located in layer 6.The properties of tectal cells in response to electrical stimulation of the optic tract and to brisk changes of diffuse illumination suggest certain neuronal connectivity patterns. The results support the idea ofintegrative functional units (assemblies) of connected cells which are involved in various perceptual processes, such as configurational prey selection expressed by T5(2) prey-selective neurons.Abbreviations A antiworm-like 16°×2° stripe stimulus with long axis perpendicular to the direction of movement - W wormlike 2°×16° stripe stimulus with long axis oriented parallel to the direction of movement - S square 8°×8° moving stimulus - ERF excitatory receptive field - IRF inhibitory receptive field - RF receptive field - EPSP excitatory postsynaptic potential - IPSP inhibitory postsynaptic potential     

Purification and characterization of a trypsin-like enzyme with fibrinolytic activity present in the abdomen of horn fly, Haematobia irritans irritans (Diptera: Muscidae)

This work describes the purification and characterization of a trypsin-like enzyme with fibrinolytic activity present in the abdomen of Haematobia irritans irritans (Diptera: Muscidae). The enzyme was purified using a one-step process, consisting of affinity chromatography on SBTI-Sepharose. The purified protease showed one major active proteinase band on reverse zymography with 0.15% gelatin, corresponding to a molecular mass of 25.5 kDa, with maximum activity at pH 9.0. The purified trypsin-like enzyme preferentially hydrolyzed synthetic substrates with arginine residue at the P1 position. The K _m values determined for three different substrates were 1.88 × 10^–4, 1.28 × 10^–4, and 1.40 × 10^–4 M for H--benzoyl-Ile-Glu-Gly-Arg-p-nitroanilide (S2222), dl-Ile-Pro-Arg-p-nitroanilide (S2288), and DL-Phe-Pip-Arg-p-nitroanilide (S2238), respectively. The enzyme was strongly inhibited by typical serine proteinase inhibitors such as SBTI (soybean trypsin inhibitor, K _i = 0.19 nM) and BuXI (Bauhinia ungulata factor Xa inhibitor, K _i = 0.48 nM), and less inhibited by LDTI (leech-derived tryptase inhibitor, K _i = 1.5 nM) and its variants LDTI 2T and 5T (0.8 and 1.5 nM, respectively). The most effective inhibitor for this protease was r-aprotinin (r-BPTI) with a K _i value of 39 pM. Synthetic serine protease inhibitors presented only weak inhibition, e.g., benzamidine with K _i = 3.0 × 10^–4 M and phenylmethylsulfonyl fluoride (PMSF) showed traces of inhibition. The purified trypsin-like enzyme also digested natural substrates such as fibrinogen and fibrin net. The protease showed higher activity against fibrinogen and fibrin than did bovine trypsin. These data suggest that the proteolytic enzyme of H. irritans irritans is more specific to proteins from blood than are the vertebrate digestive enzymes. This enzyme's characteristics may be an adaptation resulting from the feeding behavior of this hematophagous insect.     

Competitive interaction of biliverdin and bilirubin only at the primary bilirubin binding site on human albumin

The binding of biliverdin-IXα by human albumin and serum was quantitated, using three different binding techniques, to study the effects of biliverdin on bilirubin-albumin binding. The apparent equilibrium association constants (K ± SD) and binding capacities (n) of defatted albumin, pooled adult sera, and pooled umbilical cord sera for biliverdin are: K = 1.3 ± 2 × 10^{6 −1}, n = 1.00; K = 13.0 ± 3 × 10^{6 −1}, n = 0.90; and K = 6.8 ± 0.1 × 10^{6 −1}, n = 0.85, respectively. Although bilirubin binds at more than one albumin site, competitive studies showed that biliverdin binds only at the primary (highest affinity) bilirubin site. Sulfisoxazole, previously thought to compete with bilirubin for the primary binding site, was found to displace bilirubin from both primary and secondary bilirubin binding sites. Biliverdin, because of its specific binding and spectral characteristics, could be a useful probe for determining the capacity of the primary bilirubin-albumin binding site.     

A structured model for the kinetics of fungal amylase production

Summary The cell is considered to be divided into nucleic acids, proteinaceous material and storage compounds. The enzyme is believed to be constitutive but repressed by the rate of catabolism. A structured model is developed to describe the growth, amylase production and dissolved oxygen profile in the batch culture ofAspergillus oryzae.Nomenclature CA Conc. of enzyme SKB units/m³ - C_D,C_E,C_G,C_O,C_S Conc. of D.E.G. mass, oxygen, substrate kg/m³ - C_O* Mean oxygen conc. in gas-liquid interface kg/m³ - C_X Total cell conc. kg/m³ - D D-mass (proteins) kg - E E-mass (storage carbon) kg - G G-mass (necleic acids) kg - K_E Rate of usage of E-mass kg/m³/h - K_EO K_E with oxygen limitation kg/m³/h - Q Active fraction of promotor genes - - R_D,R_E,R_G Rate of production of D,E,G-mass kg/m³/h - R_O,R_S Rate of usage of oxygen, substrate kg/m³/h - R_DO,R_EO,R_GO R_D,R_E and R_G with oxygen limitation kg/m³/h - S Substrate (carbon) concentration kg/m³ - t Time h - t_o Time at which C_S = 0 h - K₁,K₂,K₃,K₂₄,K₂₅ Stoichiometric constants - - K₄,K₅,K₆,K₇ Rate constants h^–1 - K₈-K₁₂,K₁₈,K₂₀-K₂₃ Michaelis-Menten constants kg/m³ - K₂₆,K₂₆ Absorption coefficient, K₂₆ at C_X = 0 h^–1 - K₂₇ Empirical constant kg/m³ - K₁₅ Rate of enzyme formation SKB units/kg - K₁₆,K₁₇ Equilibrium constants m³/kg - K₁₉ Decay constant for mRNA h^–1     

Circularly polarized luminescence of Eu(III) complexes with chiral 1,1′-bi-2-naphtol-derived bisphosphate ligands

The interest for lanthanide circularly polarized luminescence (CPL) has been quickly growing for 10 years. However, very few of these studies have involved correlation between the dissymmetry factor (g_lum) and the chemical modifications in a series of chiral ligands. Four polymeric compounds of Eu(III) were prepared by using a series of binaphtyl derivatives for which the size of the π system as well as the number of stereogenic elements (i.e., the binaphtyl moiety) are modulated. The resulting {[Eu(hfac)₃((S)/(R)-L^x)]}_n (x = 1 and 3) and {[Eu(hfac)₃((S,S,S)/(R,R,R)-L^x)]}_n (x = 2 and 4) have been characterized by powder X-ray diffraction by comparison with the X-ray structures on single crystal of the Dy(III) analogs. In solution, the structure of the complexes is deeply modified and becomes monomeric. The nature of the ligand induces change in the shape of the CPL spectra in CH₂Cl₂ solution. Furthermore, a large |g_lum| = 0.12 of the magnetic-dipole transition for the [Eu(hfac)₃((S,S,S)/(R,R,R)-L²)] complex involving the ligand with three stereogenic elements and an extended ?? system has been measured. This report also shows CPL measurements in solid state for the series of {[Eu(hfac)₃((S)/(R)-L^x)]}_n (x = 1 and 3) and {[Eu(hfac)₃((S,S,S)/(R,R,R)-L^x)]}_n (x = 2 and 4) polymers.     

Porcine model of congenital heart defect with decreased pulmonary blood flow

A porcine model was produced to study the pathophysiology of congenital heart defect (CHD) with decreased pulmonary blood flow. Twenty piglets (1–2 months) were randomly divided as mild to moderate stenosis/T₁ group (n = 7) in which artificial atrial septal defect (ASD) with pulmonary artery banding generated a systolic pressure gradient of 20–30 mmHg; severe stenosis/T group (n = 7) group with a systolic pressure gradient of ≥30–50 mmHg; and controls/C group (n = 6) underwent sham surgery. At 1 month postoperatively, 64-slice computed tomography (CT) was performed. At 2 months, left-chest surgery was performed to measure ASD diameter, arterial blood gas, hemoglobin, and Trans-PABP. Our data show successful establishment of porcine CHD model. ASDs in T₁/T₂ groups were 8.0 ± 0.5/8.9 ± 1.4 mm, respectively. Trans-PABP showed that the pressure increase in T₂ was higher (P < 0.01) than in T₁ group. Arterial blood PaO₂ and SaO₂ of T_1/T₂ groups were significantly lower than controls. AoD was significantly lower in T₁ than in C group. Balloon dilation was significantly lower than AoD in T₁/T₂ groups. Besides, one animal in T₁, two animals in T₂ ,and one animal in C group died. We conclude that ASD with pulmonary artery banding is a successful intervention to establish such a model, and our findings may influence the treatment of patients with similar heart disease.