Style morph frequencies in Minnesota populations of Lythrum (Lythraceae)

Style morph frequencies (shortmidlong) were determined for a total of n = 11 918 plants in 16 Minnesota populations of Lythrum salicaria L. Nine populations were in the establishment phase, with population sizes ranging from n = 56 to n = 2 192. Most of these populations exceeded previously reported population sizes in the native European habitat. A nonparametric statistical test, the chi-square (²), can be used to determine if populations are at isoplethic equilibrium (111, shortmidlong); a ² value >5.99 is significant at the 5% level. Only one established population (White Bear Lake, n = 1991, ² = 3.0) fitted the null hypothesis for isoplethy, although all established populations contained all three style morphs. Pooled values for these populations indicated an excess of mids and longs, with shorts being deficient. Colonizing populations had a higher percentage of mids (54%) when compared to established populations (33.7%). Short styles were almost nonexistent (8%) in colonizing populations. Five out of the seven populations lacked at least one style morph. A review of the literature reporting style morph frequencies in tristylous L. salicaria revealed that no statistical analysis for isoplethy has been performed. Darwin originally assumed that all populations would be isoplethic, possessing equal numbers of all three style morphs, but concluded, without statistical analysis, that, instead, populations were anisoplethic. Since tests for statistical deviations from the expected frequencies (111) have not been used, ² analysis was performed. Several of these populations were at isoplethic equilibrium (Nadder su2 = 1.7, Blelham ² = 1.69, Potsdam ² = 1.5, Vestfold ² = 0.4, Buskerud ² = 5.62, Kilchberg ² = 0.35, Lausanne ² = 3.32, Canberra ² = 5.29, Massachusetts ² = 3.13), suggesting that the general conclusion of anisoplethy in tristylous L. salicaria is inappropriate.This is Scientific Journal Series Paper Number 19 128 of the Minnesota Agricultural Experiment Station     

Einfluß von Bromuracil auf die Mutationsauslösung und Inaktivierung durch UV und Röntgenstrahlen beim Phagen χ

Zusammenfassung Durch Anreicherung in BUdR- und FUdR-haltigem Medium wurde in die DNS des Serratiaphagen Bromuracil (BU) eingebaut. Im CsCl-Gradienten zeigte die Dichte der BU--Partikel einen Ersatz des Thymins durch BU von 25 bis 30% an. Die Häufigkeit zweier Plaquetypmutanten (c und b) war in der BU--Population signifikant (durchschnittlich 1,4 bzw. 2,4), die des dritten Typs (e) nur insignifikant über die in BU-freien Phagen erhöht. Im Vergleich zu letzterem betrug die absolute Häufigkeit der zusätzlichen c- und b-Mutanten in BU- 2,2 × 10^–4 bzw. 1,1 × 10^–4.Die UV-Inaktivierung von BU- war etwa um den Faktor 1,40 höher als die des normalen . Die Inaktivierung durch Röntgenstrahlen war dagegen nur um das 1,14fache erhöht. Die Häufigkeit der durch Röntgenstrahlen induzierten Plaquemutationen wurde durch den BU-Einbau nicht merklich beeinflußt. Dagegen war die UV-Induktion der Mutationen sehr viel mehr verstärkt als die UV-Inaktivierung. Die Sensibilisierungsfaktoren der drei Mutantentypen waren verschieden und am höchsten bei niederen UV-Dosen (3,4, 5,0 und 22 für c, b bzw. e). Das bedeutet eine Annäherung der Dosiskurven an linearen Verlauf. Die zur Auslösung von Mutationen erforderliche Trefferzahl wird somit durch BU-Einbau vermindert. Für -normal entsprachen die Kurven der UV-Mutationsinduktion dem 2-Treffertyp. Es wird geschlossen, daß die Hemmung der Dunkelreaktivierung (HCR) der Letalläsionen und Prämutationen in BU-DNA nicht die einzige Ursache für die Unterschiede in den UV-Sensibilitäten ist, sondern daß die Bildung anderer UV-Produkte als in der normalen DNA ebenfalls eine Rolle spielt.

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Summary Bromouracil (BU) was incorporated into the DNA of theSerratiaphage by means of culture in a medium with BUdR and FUdR. The density of BU-x particles in the CsCl-gradient indicated a replacement of about 24 to 32 % of the thymine by BU. The frequency of two types of plaquemutants (c and b) in the BU--population was increased significantly above the frequencies in BU-free phage by average factors of 1.4 and 2.4, resp. A third mutant type (e) was increased less. The absolut frequencies of additional c- and b-mutants in BU- compared with normal were about 2.10^–4 and 1.10^–4, resp.The UV-inactivation of BU- was higher by a factor of about 1.40 than that of normal , the inactivation by X-rays was only 1.14 times higher. The X-ray induced plaquemutation frequencies were not remarkably influenced by incorporated BU, but UV-mutation-induetion was increased much stronger than UV-inactivation. The sensitization factors were different for the three mutation types and highest at low UV-doses (3.4, 5.0 and 22 for c, b and e resp.). The UV-dose curves of mutation induction in normal are of the 2 hit type, but for BU- they were significantly less curved indicating the participation of 1-hit-processes in premutation production. It is concluded that inhibition of dark repair (HCR) of lethal lesions and premutations in BU-DNA is not the only reason for the differences in UV-sensitivities but that production of other species of UV-products in BU-DNA than in normal DNA plays also a role.

     

ABO blood groups,leprosy, and serum proteins

Summary In 683 leprosy patients from Chiang Mai, Thailand, the associations between ABO blood groups, type and clinical features of leprosy, and electrophoretically identifiable serumprotein fractions (albumins: ₁-, ₂-, - and -globulins) were examined. Besides, the blood group frequencies in 388 leprosy patients were compared with suitable controls. Blood groups A and AB turned out to be somewhat more frequent in patients than in controls. Combined analysis with 31 series from literature reports gave X=1.0776; ²=1)=12.232. In comparisons within our group of patients which contained almost exclusively lepromatous and dimorphous patients a certain tendency towards more severe involvement of blood group A was observed within the lepromatous group and a higher frequency of eye involvement in group A was (weakly) significant (²=1)=6.188).As to serum proteins ₁- and ₂-globulins were decreased (weakly) significantly in blood group A patients who were at least 40 years old. Furthermore, a number of relationships of serum protein fractions with age, sex, and state of the infection, most of which are known from the literature, could be confirmed.     

Measuring the chi 1 torsion angle in protein by CH-CH cross-correlated relaxation: a new resolution-optimised experiment

Here we introduce an experiment with high sensitivity and resolution for the measurement of CH-CH dipolar-dipolar cross-correlated relaxation rates (CCRR) in protein side-chains. The new methodology aims to the determination of structural and dynamical parameters around the torsion angle ₁ by measuring CH-CH cross-correlated relaxation rates. The method is validated on the protein ubiquitin: the ₁ angles determined from the CCRR data are compared with the ₁ angles of a previously determined NMR structure. The agreement between the two data sets is excellent for most residues. The few discrepancies that were found between the CCR-derived ₁ angles and the angles of the previously determined NMR structure could be explained by taking internal motion into account. The new methodology represents a very powerful tool to determine both structure and dynamics of protein side-chains in only one experiment.     

Analysis of local conformation of membrane-bound and polycrystalline peptides by two-dimensional slow-spinning rotor-synchronized MAS exchange spectroscopy

2D slow-spinning, rotor-synchronized MAS exchange spectroscopy (SSRS-MASE) was applied to study local secondary structure of three structurally different peptides, two of which were membrane-bound. Each peptide was ¹³C carbonyl labeled at two adjacent residues in the peptide backbone. In general, this methodology is attractive for membrane-bound peptides because of its lenient spinning, decoupling, and RF homogeneity requirements.For a single set of raw SSRS-MASE data, two linearly independent methods exist for obtaining a 2D spectrum and each spectrum can be fit to obtain conformational constraints. An approach is described for combining the results of these two fits and this method is shown to work for spectra with both resolved and unresolved labeled site resonances. A spectrum is often fit well to a few different conformations which have somewhat different values of the fitting parameter ². A simple statistical theory is developed which relates the ² difference between a local minimum and the global minimum ² to the likelihood that the local minimum conformation is the correct structure. Because uncertainty in the simulated data can also contribute to the overall fitting uncertainty, an empirical method is described for incorporating the simulation uncertainty into the ² analysis.These data analysis methods were tested on polycrystalline Ala-Gly-Gly and then applied to the membrane-bound melittin and HIV-1 fusion peptides. Melittin gave a best-fit helical structure at Ala-4 while the fusion peptide gave a good-fit strand structure at Phe-8. The melittin analysis is in agreement with the known overall structure of this peptide.     

Partial mispairing and crossing-over between β0 and δ genes as the origin of the δ β0 thalassemia gene

Summary Two double heterozygous ⁰/⁰ thalassemic sibs of Mexican descent were studied. The father had a ⁰/⁰ genotype, while the mother, one sib and several maternal relatives were ⁰/⁰ heterozygotes. Parental consanguinity and an apparently low frequency of thalassemia among Mexicans suggested a possible common origin of both ⁰ and ⁰ genes. A hypothesis to explain such a possibility is proposed on the basis of a partial mispairing between ⁰ and genes followed by a crossing-over which would results in a ⁰ recombinant gene. This hypothesis could also be extended to explain the 22 gluala, 22 alaglu and 116 arghis Hb variants as recombinants from double crossing-over between and mispaired genes for which the name interstitial-Lepore is proposed.     

A Trp in chi space

Our aim is to identify and synthesise a family of tryptophan mimetics which thoroughly explore chi space and then incorporate them into selected ligands for biological receptors e.g. Tachykinin NK₁. This project is considered important as only the - angles have previously been explored; obtaining a greater understanding of the spacial orientation of the side chain in chi space (₁-₂) should prove invaluable to the future design of peptidomimetics. The amino acid tryptophan was selected as it has proved pivotal in many pharmaceutic drug programmes.     

Pulse schemes for the measurement of3 JC′Cγ and3 JNCγ scalar couplings in 15N,13C uniformly labeled proteins

Pulse sequences are presented for the measurement of³J_CC and³J_NC scalar couplings for allC containing residues in¹⁵N,¹³C uniformly labeled proteins. The methodsdescribed are based on quantitative J correlation spectroscopy pioneered byBax and co-workers [Bax et al. (1994) Methods Enzymol., 239, 79–105].The combination of ³J_CC and³J_NC scalar coupling constants allows theassignment of discrete rotameric states about the ₁ torsion angle in cases where such states exist or, alternatively,facilitates the establishment of noncanonical ₁conformations or the presence of rotameric averaging. The methods areapplied to a 1.5 mM sample of staphylococcal nuclease.     

2D relayed anisotropy correlation NMR: Characterization of the 13C′ chemical shift tensor orientation in the peptide plane of the dipeptide AibAib

An approach to the determination of the orientation of the carbonyl chemical shift (CS) tensor in a ¹³C-¹⁵N-¹H dipolar coupled spin network is proposed. The method involves the measurement of the Euler angles of the ¹³C-¹⁵N and ¹⁵N-¹H dipolar vectors in the ¹³C CS tensor principal axes system, respectively, via a ¹³C-¹⁵N REDOR experiment and by a 2D relayed anisotropy correlation of the ¹³C CSA (₂) and ¹⁵N-¹H dipolar interaction (₁). Via numerical simulations the sensitivity of the ₁ cross sections of the 2D spectrum to the Euler angles of the ¹⁵N-¹H bond vector in the ¹³C CSA frame is shown. Employing the procedure outlined in this work, we have determined the orientation of the ¹³C CS tensor in the peptide plane of the dipeptide AibAib-NH₂ (Aib = -aminoisobutyric acid). The Euler angles are found to be (_CN, _CN) = (34° ± 2°, 88° ± 2° ) and (_NH, _NH) = (90° ± 10°, 80° ± 10° ). From the measured Euler angles it is seen that the ₃₃ and ₂₂ components of the ¹³C CS tensor approximately lie in the peptide plane.     

Analysis of 1H chemical shifts in DNA: Assessment of the reliability of 1H chemical shift calculations for use in structure refinement

The reliability of ¹H chemical shift calculations for DNA is assessed by comparing the experimentally and calculated chemical shifts of a reasonably large number of independently determined DNA structures. The calculated chemical shifts are based on semiempirical relations derived by Giessner-Prettre and Pullman [(1987) Q. Rev. Biophys., 20, 113–172]. The standard deviation between calculated and observed chemical shifts is found to be quite small, i.e. 0.17 ppm. This high accuracy, which is achieved without parameter adjustment, makes it possible to analyze the structural dependencies of chemical shifts in a reliable fashion. The conformation-dependent ¹H chemical shift is mainly determined by the ring current effect and the local magnetic anisotropy, while the third possible effect, that of the electric field, is surprisingly small. It was further found that for a double helical environment, the chemical shift of the sugar protons, H2 to H5, is mainly affected by the ring current and magnetic anisotropy of their own base. Consequently, the chemical shift of these sugar protons is determined by two factors, namely the type of base to which the sugar ring is attached, C, T, A, or G, and secondly by the -angle. In particular, the H2 shift varies strongly with the -angle, and strong upfield H2 shifts directly indicate that the -angle is in the syn domain. The H1 shift is not only strongly affected by its own base, but also by its 3-neighboring base. On the other hand, base protons, in particular H5 of cytosine and methyl protons of thymine, are affected mainly by the 5-neighboring bases, although some effect (0.2 ppm) stems from the 3-neighboring base. The H2 protons are mainly affected by the 3-neighboring base. As a result of these findings a simple scheme is proposed for sequential assignment of resonances from B-helices based on chemical shifts.     

Genetic Determinants of Predisposition to Bronchial Asthma

The ratio between the normal (+) and null (0) alleles of the genes encoding glutatione S-transferases M1 (GSTM1) and T1 (GSTT1) were studied in normal individuals from northwestern Russia (control group) and in patients with bronchial asthma (BA). The frequency of the GSTM1 0/0 genotype in the population sample was statistically significantly lower (37.8%) than in the BA patients (82.1%; ² = 16.8;P< 0.001; _W² = 15.7; = 0.01). For the GSTT1 gene, similar data were obtained. The frequency of the GSTT1 0/0 genotype in healthy donors was statistically significantly higher (16.3%) than in the BA patients (73.7%; ² = 28.5;P < 0.001; _W² = 23.22; = 0.01). A significant preponderance of the compound homozygotes for the GSTM1 and GSTT1 null alleles among the BA patients was observed. The frequency of the GSTM1 0/0, GSTT10/0 individuals among the patients was 57.9%, while it was only 4.7% among the controls (² = 27.4; P < 0.001).     

Theoretical studies on the necessary number of components in mixtures

Summary Theoretical studies on the optimal numbers of components in mixtures (for example multiclonal varieties or mixtures of lines) have been performed according to phenotypic yield stability (measured by the parameter variance). For each component i, i = 1, 2,..., n, a parameter u_i with 0 u_i 1 has been introduced reflecting the different survival and yielding ability of the components. For the stochastic analysis the mean of each u_i is denoted by u ₁ and its variance by _i ² For the character total yield the phenotypic variance V can be explicitly expressed dependent on 1) the number n of components in the mixture, 2) the mean of the _i ² 3) the variance of the _i ² 4) the ratio and 5) the ratio _i ² /² where denotes the mean of the u _i and _u ² is the variance of the u _j. According to the dependence of the phenotypic stability on these factors some conclusions can be easily derived from this V-formula. Furthermore, two different approaches for a calculation of necessary or optimal numbers of components using the phenotypic variance V are discussed: A. Determination of optimal numbers in the sense that a continued increase of the number of components brings about no further significant effect according to stability. B. A reduction of b % of the number of components but nevertheless an unchanged stability can be realized by an increase of the mean of the u _i by 1% (with and _u ² assumed to be unchanged). Numerical results on n (from A) and 1 (from B) are given. Computing the coefficient of variation v for the character total yield and solving for the number n of components one obtains an explicit expression for n dependent on v and the factors 2.-5. mentioned above. In the special case of equal variances, _i ² = _o ² for each i, the number n depends on v, x = (₀/)² and y = (_u/)². Detailed numerical results for n = n (v, x, y) are given. For x 1 and y 1 one obtains n = 9, 20 and 79 for v = 0.30, 0.20 and 0.10, respectively while for x 1 and arbitrary y-values the results are n = 11, 24 and 95.This publication is an extended version of a lecture given at the 1984-EUCARPIA meeting (Section Biometrics in Plant Breeding) in Stuttgart-Hohenheim (Federal Republic of Germany)     

Existence and uniqueness of a sharp travelling wave in degenerate non-linear diffusion Fisher-KPP equations

In this paper we use a dynamical systems approach to prove the existence of a unique critical value c ^* of the speed c for which the degenerate density-dependent diffusion equation u _ct = [D(u)u _x ] _x + g(u) has: 1. no travelling wave solutions for 0 < c < c ^*, 2. a travelling wave solution u(x, t) = (x - c ^* t) of sharp type satisfying (– ) = 1, () = 0 ^*; '(^*–) = – c ^*/D'(0), '(^*+) = 0 and 3. a continuum of travelling wave solutions of monotone decreasing front type for each c > c ^*. These fronts satisfy the boundary conditions (– ) = 1, '(– ) = (+ ) = '(+ ) = 0. We illustrate our analytical results with some numerical solutions.     

Polar bears make little use of terrestrial food webs: evidence from stable-carbon isotope analysis

Summary The mean stable-carbon isotope ratios (¹³C) for polar bear (Ursus maritimus) tissues (bone collagen –15.7, muscle –17.7, fat –24.7) were close to those of the same tissues from ringed seals (Phoca hispida) (–16.2, –18.1, and –26.1, respectively), which feed exclusively from the marine food chain. The ¹³C values for 4 species of fruits to which polar bears have access when on land in summer ranged from –27.8 to –26.2, typical of terrestrial plants in the Arctic. An animal's ¹³C signature reflects closely the ¹³C signature of it's food. Accordingly, the amount of food that polar bears consume from terrestrial food webs appears negligible, even though some bears spend 1/3 or more of each year on land during the seasons of greatest primary productivity.     

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     

Use of15N/14N rations to evaluate the food source of the mysid,Neomysis intermedia Czerniawsky,in a eutrophic lake in Japan

The stable isotope ratios of nitrogen were measured in the mysid,Neomysis intermedia, together with various biogenic materials in a eutrophic lake, Lake Kasumigaura, in Japan throughout a year of 1984/85. The mysid, particulate organic matter (POM, mostly phytoplankton), and zooplankton showed a clear seasonal change in ¹⁵N with high values in spring and fall, but the surface bottom mud did not. A year to year variation as well as seasonal change in ¹⁵N was found in the mysid. The annual averages of ¹⁵N of each material collected in 1984/85 are as follows: surface bottom mud, 6.3 (range: 5.7–6.9); POM, 7.9 (5.8–11.8); large sized mysid, 11.6 (7.7–14.3); zooplankton, 12.5 (10.0–16.4); prawn, 13.2 (9.9–15.4); goby, 15.1 (13.8–16.7). The degree of¹⁵N enrichment by the mysid was determined as 3.2 by the laboratory rearing experiments. The apparent parallel relationship between the POM and the mysid in the temporal patterns of ¹⁵N with about 3 difference suggests the POM (mostly phytoplankton) as a possible food source ofN. intermedia in this lake through the year.     

A DFT investigation of conformational geometries and interconversion equilibria of phenylthiosemicarbazone and its complexation with zinc

The geometrical structures of phenylthiosemicarbazone (HAPhTSC) conformers have been obtained by geometry optimizations using density functional theory (DFT) calculations at the B3LYP/6-31G(d) and B3LYP/6-311G(d,p) levels of theory. Six thioamino and 24 thioimino tautomers of HAPhTSC have been found. Six tautomerization reactions between thioamino and thioimino tautomers occurring via transition states and their corresponding activation energies have been obtained. Conformational pathways for tautomerizations and interconversions of HAPhTSC conformers have been presented. Tautomerization between the most stable species of thioamino (Atttcc) and its thioimino (Itttcct) tautomer is an endothermic reaction, H⁰=18.17 kcal mol^–1 and its log K=–13.74, at 298.15 K. Thermodynamic quantities of tautomerizations, interconversions of HAPhTSC conformers and their equilibrium constants are reported. The geometry of the zinc complex with HAPhTSC, found as a Zn(HAPhTSC)₂Cl₂ structure, has been obtained using B3LYP/6-31G(d) calculations. Binding of the Zn(HAPhTSC)₂Cl₂ complex is an exothermic and spontaneous reaction.Figure Conformational notation defined as a name consisting of a letter A for a thioamino tautomer followed by c for cis or t for trans isomerism of five dihedral angles of (C4-C3-C2-N3), (C3-C2-N3-N2), (C2-N3-N2-C1), (N3-N2-C1-N1) and (N2-C1-N1-H2), serially, or a letter I for b thioimino tautomer followed by c for cis or t for trans isomerism of six dihedral angles of (C4-C3-C2-N3), (C3-C2-N3-N2), (C2-N3-N2-C1), (N3-N2-C1-N1), (N2-C1-N1-H2) and (N2-C1-S-H1), serially.Electronic Supplementary Material Supplementary material is available for this article at     

Problems in estimating growth rates of marine phytoplankton from short-term14C assays

Growth rate estimates () of phytoplankton populations that were sampled from nitrogen-limited continuous cultures and then incubated for short durations in batch culture with added¹⁴C-HCO₃ ^– were significantly different than steady-state growth rates () for 3 of 5 marine phytoplankton species. Two diatoms,Thalassiosira weissflogii andChaetoceros simplex, displayed virtually identical growth rates (=) over a wide range of, whereas for a third diatom,Phaeodactylum tricornutum, was overestimated by an average of 40% compared to. In contrast, was underestimated by the¹⁴C technique for the two remaining species: up to 40% at a steady-state of 1.0 day^–1 for the chlorophyteDunaliella tertiolecta and up to 100% at of 1.4 day^–1 for the haptophytePavlova lutheri. For the latter two species the divergence between and appeared to increase with increasing steady-state. A simple model of labeled and total carbon flow between the aqueous phase and cellular biomass was constructed to demonstrate that respiration was negligible when=, but was significant when>. In the cases in which<, a rapid physiological alteration presumably took place once the steady state was disturbed and cells were placed in the incubation chambers, which perhaps was related to the nutritional state of the cultures at the time of sampling. Questions thus are raised regarding our ability to measure accurately primary productivity from shipboard experiments with confined samples of phytoplankton from nutrient-impoverished waters that probably are less hardy than the laboratory cultures used in these studies.     

The α2 cDNA sequence of human haptoglobin carries a bacterial promoter functionalin vivo

Various constructions of human haptoglobin (Hp) cDNA coding either for the complete ^2FS precursor protein or only for the subunit have been placed under the control of the P_R promoter in the bacterial expression vector pCQV2 (Queen, 1983). In addition to the expected 45,000 dalton polypeptide synthesized after induction of the P_R promoter, the complete ^2FS constructions constitutively express a smaller polypeptide of 30,000 dalton corresponding to a truncated Hp protein. Computer analysis of the HpcDNA revealed the presence of two strong potential bacterial promoters (²P_F and ²P_S) located in the duplicated ^2FS sequence. Both Hp promoter signals are followed by potential mRNA start sites and ribosome binding sites at a compatible distance from initiation codons. In addition, the Hp² cDNA sequence, when fused upstream to the cDNA coding for ¹-antitrypsin, constitutively promotesin vivo the efficient expression of an hybrid protein specifically recognized by antibodies raised against ¹-antitrypsin or haptoglobin.