Proanthocyanidin polymers of fodder legumes

The structure of the condensed tannins of the most common fodder legumes is described. The number- ($\text{M}$_n) and weight-average ($\text{M}$_w ) MW of the polymers have been determined and most legume tannins have an approximately normal distribution of MWs with $\text{M}$_n values of 2000–4000.     

Characterizations and constructions of reverberating networks

Consider the family $\text{G}$_n of all n neuron networks whose dynamical behaviors are described by Caianiello's neuronic equations, and also its subfamily $\text{R}$_n of all reverberating networks each of whose neuronic equations have only periodic solution (states), i.e., without having any transient states. This paper is specifically concerned with characterizations of the subfamily $\text{R}$_n. First, we show that $\text{R}$_n is contained in a subfamily $\text{S}$_n of $\text{G}$_n consisting of all self-dual networks. We introduce Chow's matrix corresponding to each network of $\text{S}$_n, using Chow parameters and some algebraic operations {$\text{2}$_α} applied to the coefficient matrix of the network in $\text{S}$_n, such as interchanges of coefficients between two neurons or changes of their signs. Then we give some necessary conditions on Chow's matrix under which any network in $\text{S}$_n belong to $\text{R}$_n, and a necessary and sufficient condition on the coefficient matrix. We also discuss relations between Chow's matrix and the maximum period of reverberations. In particular, it is shown that Chow's matrix of a network in $\text{R}$_n is symmetric if and only if the maximum period of reverberations is less than three. By virtue of these results, we propose two methods of construction of networks in $\text{R}$_n. The first method is an inductive construction. The second is based on the algebraic operations.     

A novel in vitro method for demonstrating proestrogens. Metabolism of methoxychlor and o,p'DDT by liver microsomes in the presence of uteri and effects on intracellular distribution of estrogen receptors.

A method for demonstrating proestrogens $\text{in}$$\text{vitro}$ has been developed. The method involves the incubation of the potential proestrogen with liver microsomes and NADPH in the presence of rat uteri, followed by examination of the effects of metabolism of the compound on the distribution of uterine estrogen receptor (R) in the cytosol (R_c) and in the nucleus (R_n). Thus, we examined whether DDT derivatives, which possess estrogenic activity $\text{in}$$\text{vivo}$, exhibit pro-estrogenic properties $\text{in}$$\text{vitro}$. Using this method, it appears that methoxychlor is a proestrogen, since the presence of microsomal enzymatic activity is required for methoxychlor to elicit translocation of uterine R_c into the nucleus, namely, the lowering of R_c and elevation of R_n. By contrast, o,p'DDT was active $\text{per}$$\text{se}$ in translocating R_c and did not require the presence of microsomal enzymes for activity.     

Linear oligopeptides. 56. Critical size for development of β-and α-helical structures of monodispersed homo-l-oligomethionines in the solid state

The infrared absorption properties of monodispersed, chemically and optically pure ‘amino-PEG’-bound linear homooligopeptides having the general formula $\text{t-}\text{Bx(}\text{l}\text{-Met)}{}_{\mathrm{n}}\text{NHPEG}$, n = 1–15 and H₂⁺(l-Met)_nNHPEG, n = 1–14 have been investigated in the solid state. The critical sizes for development of the β-structure and α-helix (n = 3 and n = 13, respectively), and the effect, on the latter, of the solvent from which the solid samples are cast, have been established.     

Proton and carbon magnetic resonance studies of the synthetic polypentapeptide of elastin.

Proton and ¹³C magnetic resonance studies are reported on the synthetic polypentapeptide of elastin, HCO-(Val₍₁₎-Pro₍₂₎-Gly₍₃₎-Val₍₄₎-Gly₍₅₎)_n-Val-OMe, where n ∼- 18. Temperature and solvent dependence of peptide N$\text{H}$ chemical shift and solvent dependence of peptide carbonyl chemical shift were used to delineate these moieties preliminary to identification of secondary structure.Based on these studies it is proposed, for the organic solvents of dimethyl sulfoxide, methanol, and low-temperature trifluoroethanol, that dynamic hydrogen bonds form in order of decreasing frequency of occurrence between the Val₍₁₎$\text{C}$O and the Val₍₄₎ N$\text{H}$ (a β-turn), between the Gly₍₃₎ N$\text{H}$ and the Gly₍₅₎$\text{C}$O (an 11-atom, hydrogen-bonded ring), and a more limited interaction between the Gly₍₃₎$\text{C}$O and the Gly₍₅₎ N$\text{H}$ (a γ-turn).Arguments are presented that relate the conformational features proposed above to the coacervate, which is a filamentous state.     

The surface active properties and anti-bacterial activity of the compounds, trans-[Rh(L)4Cl2]Cl·nH2O

The antibacterial activity and surfactant activity of the compounds trans-[Rh(L)₄Cl₂]Cl·nH₂O increase in the order L = pyridine<4-methylpyridine<4-ethylpyridine<4-n-propylpyridine.As surfactants, the compounds are far more effective at reducing the interfacial tension, $\text{n}\text{-hexadecane}\text{H}{}_2\text{O}$, than the surface tension, $\text{H}{}_2\text{O}\text{air}$.The most effective and efficient surfactant in this series, trans-[Rh(4-n-propylpyridine)₄Cl₂]Cl·H₂O, can cause the leakage of intracellular manganese ions from the gram-positive bacteria, Bacillus brevis ATCC 9999, at a concentration of 130 ppm but there is no observable effect on the retention of intracellular manganese ions at the minimum concentration required to prevent growth of this organism (～0.6 ppm at 23°C in nutrient broth).At 130 ppm, trans-[Rh(4-n-propylpyridine)₄Cl₂]Cl·H₂O does not cause the loss of intracellular manganese ions from the gram-negative bacteria, Escherichia coli JS-1. In this case, a concentration of at least 63 ppm of this rhodium compound is required to prevent the growth of this organism in M9TUH medium at 35°C.On the basis of these results, it is suggested that gross membrane disruption effects caused by the surfactants trans-[Rh(L)₄Cl₂]Cl·nH₂O are not directly responsible for their observed antibacterial action.     

Quantitative studies on prostaglandin synthesis in man. II. Determination of the major urinary metabolite of prostaglandins F1 alpha and F2 alpha

A method was developed for quantitative determination of 5α,7α-dihydroxy-11-ketotetranor-prostane-1,16-dioic acid, the major urinary metabolite of prostaglandins F_1α and F_2α in man. The method was based on the use of the O-methyloxime derivative of [5β-³H; 10,10,12,12-²H₄]5α,7α-dihydroxy-11-ketotetranor-prostane-1,16-dioic acid as internal standard and determination of ratios between unlabeled and deuterium-labeled molecules by multiple-ion analysis. Excretion values found for healthy human subjects were: males, $\text{10.8–59.0 μ}\text{g}\text{24 hr}$ (n = 10, mean value, 24.0 ± 17.2 (SD) μg) and females, $\text{7.6–13.6 μ}\text{g}\text{24 hr}$ (n = 10, mean value, 10.5 ± 2.1 (SD) μg).     

Secondary structure of peptides: 15. 13C n.m.r. CP/MAS study of solid elastin and proline-containing copolyesters

In order to study the chemical shifts and the cis—trans isomerism of prolyl units neighbouring glycine or other amino acids, 75.4 MH_z¹³C nuclear magnetic resonance (n.m.r.) cross-polarization/magic angel spinning (CP/MAS) spectra of the following solid oligopeptides and sequence polypeptides were measured: Z-Gly-Pro-OH,Z-Gly-Pro-Gly-Gly-OEt,Z-Gly-Pro-Ala-Ala-OMe,(Gly-Pro-Gly)_n,(Gly-Pro-Ala)_n,(β-Ala-Pro)_n and $\text{(δ-Ava-Pro)}{}_{\mathrm{<mtext>n</mtext>}}\text{(δ-Ava=δ-}\text{aminovaleric acid}$). Whereas all these oligo- and polypeptided contain exclusively trans X-Pro bonds, both cis and trans peptide bonds were found in a polypeptide prepared by copolymerization of glycine- and $\text{proline-}\text{N}\text{-carboxyanhydrides}$ in pyridine. On the basis of these model compounds, the ¹³C n.m.r. CP/MAS spectra of solid elastin allows the following conclusions. Almost all X-Pro bonds assume the trans conformation, most alanine and leucine units form α-helical chain segments, whereas only a small fraction of β-sheet structure is present. A 30.3 MHz ¹⁵N n.m.r. CP/MAS spectrum of solid elastin confirms that ～25% of all amino acids assume the α-helical structure. A model of elastin is discussed consisting of an amorphous phase, α-helical chain segments and helical segments of still unknown pitch.     

Factors affecting proton translocation by facultative methylotrophs

The general properties of respiration-driven proton translocation by the two facultative methylotrophs, Pseudomonas AM1 and Pseudomonas extorquens, were similar to those of other bacteria. The stoichiometry of H⁺ extruded/O atom consumed ($\text{H}\text{←}{}^{\mathrm{+}}\text{O}$) during respiration with a particular substrate depended, however, on the concentration of the permeant anion SCN^? used to abolish the membrane potential and on the physiological state of the organism. This variability makes the use of proton translocation data of dubious value in the elucidation of electron-transport pathways, at least in these species, unless the physiological condition of the organisms can be accurately described and reproduced. Methanol oxidation was inhibited by SCN^? but substitution of valinomycin for most of the SCN^? during pulse oxidant experiments allowed measurement of proton translocation when methanol was the substrate. Starved organisms were used to eliminate ambiquity as to whether added test substrates or endogenous reserve materials were being oxidised. Viability remained high during starvation and endogenous O₂ uptake remained detectable long after endogenously driven proton translocation was undetectable. In the absence of endogenously driven proton translocation, measured $\text{H}\text{←}{}^{\mathrm{+}}\text{O}$ stoichiometries differed substantially from those when it was present, suggesting that the physiological state of the organisms is an essential parameter in assessing proton translocation data.     

Attenuation of noradrenergic neurotransmission by the thromboxane synthetase inhibitor,UK 38,485

The purpose of this study was to determine the effects of chronic administration of the thromboxane synthetase inhibitor, UK 38,485, on noradrenergic neurotransmission. Male Sprague Dawley rats (n=14) were treated once daily with either UK 38,485 (100 mg/kg; n=7) or the vehicle of UK 38,485 (olive oil; n=7) by gavage. The dose of UK 38,485 chosen was sufficient to inhibit $\text{ex vivo}$ platelet TXB₂ production by >90% for 24 hours. One week into the treatment animals were prepared for $\text{in situ}$ perfusion of their mesenteric vascular beds. Vasoconstrictor responses to both exogenous norepinephrine and periarterial nerve stimulation were determined both before and during an infusion of angiotensin II (9ng/min) into the superior mesenteric artery. UK 38,485 significantly (P<0.02) attenuated the vascular response to periarterial nerve stimulation without altering the vascular response to either norepinephrine or angiotensin II. UK 38,485 did not influence the baseline perfusion pressure, the mean arterial blood pressure or the potentiation of neurotransmission by angiotensin II. These data indicate that in the $\text{in situ}$ rat mesentery UK 38,485 attenuates the release of neurotransmitter from sympathetic nerve terminals.     

On the oscillatory transient stage structure of yeast population

We say that a cell of budding yeast, Saccharomyces cerevisiae, is of stage n when it has n bud scars and hence it has produced n daughters. We then divide the total population X into stage classes according to X = Σ_nX_n where X_n is the number of cells which have produced n daughters. The present work deals with the fractions $\text{X}{}_{\mathrm{n}}\text{X}$ in the transient phase before the demographic equilibrium, where the fractions attain stationary values, is reached. It is found that the oscillatory (in time) stage structure is possible provided that (i) the generation time of a virgin (n = 0) cell differs from those of matured (n ≥ 1) cells by more than the sum of respective standard deviations, and (ii) both the initial stage structure and the initial distribution over the cell cycle phase differ appreciably from those prevailing in the demographic equilibrium.     

Hyaluronic acid: a double-helical structure in the presence of potassium at low pH and found also with the cations ammonium, rubidium and caesium.

An anti-parallel double-helical structure is proposed for hyaluronic acid in the presence of the cations K ⁺, NH⁺₄, Rb⁺ and Cs⁺. In particular the crystalline phase containing potassium ions, and in a defined pH range, has been determined and refined against the X-ray diffraction amplitudes. The reflections in the diffraction pattern index on a tetragonal unit cell (a = b = 1.714 nm, c (fibre axis) = 3.28 nm) with observed systematic absences of the form h + k + l = 2n for general hkl reflections and l = 4n (where n is an integer) for 001 reflections. Two double-helical molecules pass through the unit cell at positions ($\text{1}\text{4}\text{,}\text{1}\text{4}\text{, 0}$) and ($\text{3}\text{4}\text{,}\text{3}\text{4}\text{, 0}$) as defined by space group I4₁22. Each chain forms a contracted (axial advance per disaccharide repeat of 0.82 nm) 4-fold left-handed helix which intertwines with a neighbouring chain of opposite polarity about a common axis. Features of the structure are the positioning of the carboxyl group toward the core of the double helix and the presence of hydrophobic and hydrophilic pockets between adjacent double helices. The state of protonation of the hyaluronate molecule is discussed in the light of the infrared evidence. Common physicochemical features of these four cations which promote this particular doublehelical conformation for hyaluronate are considered.     

Determination of oxidation-reduction potentials by spectropolarimetric titration: application to several iron-sulfur proteins

The oxidation-reduction potential (E₀?') and the stoichiomotry of electron equivalents (n) of several iron—sulfur proteins determined by direct potentiomctric titration in the presence of redox-mediator dyes and monitored by concomitant changes in circular dichroism are reported. The absence of circular dichroism or changes in circular dichroism by the redox mediators undergoing redox transitions forma the operational basis for the spectropolarimetric titration. The applicability of the method was explored by extensive investigations with spinach ferredoxin.The redox potential and stoichiometry values determined by spectropolarimetric titration are: (1) a plant-type (spinach) ferredoxin, E₀?' = —0.423 V, pH-independent in the range 8.0–9.5; n = 1, (2) a ferredoxin from the nonphotosynthetic bacterium, Clostridium pasteurianum, E₀?' = —0.390 V at pH 8.8, $\text{ΔE}\text{Δ}\text{pH}\text{? 30}\text{mV}$ for pH rangc 6.8–8.8; n = 2, (3) a ferredoxin from the photosynthetic bacterium, Chromatium, E₀′ = ?0.489 V at pH 9.0 and 9.5; n = 2, and (4) an iron sulfur protein designated “Protein II” isolated from Azotobactetr vinelandii, E₀? = ?0.225 V at pH 7.0 and 8.0; n, = 1.An automatic-titration method with a continuously recorded titration curve was demonstrated using the azotobacter Protein II. The general applicability of the spectropolarimetric-titration technique to other biological electron carriers and some experimental factors are discussed.     

Thyroid hormone-divalent cation interactions. Effect of thyroid hormone on mitochondrial calcium metabolism

The effect of l-triiodothyronine (T₃) on calcium metabolism was studied in mitochondria isolated from thyroidectomized rats. The maximal rate of low-level calcium uptake (V) was enhanced by T₃ in the absence or the presence of added acetate; the $\text{K}{}_{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}$ value was unchanged. Further, the rate constant (K_e) derived from measurement of the efflux of calcium was stimulated 10-fold upon the addition of T₃. This stimulating effect was not seen in the presence of acetate. In studies of adenine nucleotide translocation, calcium stimulated the translocation of ATP out of these mitochondria, but only in the presence of T₃. These results suggest that T₃ alters calcium ion mobility within the mitochondrial membrane and hence modulates calcium-dependent metabolic processes. The precise locus of this affect remains to be identified.     

Activation of the β-galactoside transport system in escherichia coli ML-308 by n-alkanols. Modification of lipid-protein interaction by a change in bilayer fluidity

The net rate of transport of $\text{o-}\text{nitrophenyl}\text{-β-}\text{d}\text{-}\text{galactopyranoside}$ by Escherichia coli ML-308 is increased at temperatures below the apparent phase transition of the lipid bilayer in the presence of n-alkanols. The degree of activation produced is determined both by the concentration and chain length of the n-alkanol used. At low concentrations n-alkanols “activate” transport, but do not cause either cell lysis or denaturation of β-galactosidase.Arrhenius plots of the kinetic constants for transport indicate the K_m shows discontinuity with increasing temperature, while the slope for V changes only gradually. The presence of 10.5 mM n-hexanol increases the value of both K_m and V at low temperature. A comparison of these data to those obtained at a single substrate concentration (1.85 mM o-nitrophenyl-β-d-galactopyranoside) suggests the biphasic behavior of Arrhenius plots at that concentration may be attributed to changes in the K_m for the transport process.     

A stochastic model for the economic management of a renewable animal resource

An optimal economic harvesting policy, which maximizes the present value of an animal population, capable of renewing itself, is discussed. It is assumed that, unhindered, the successive population levels, X_n, form a Markov chain, with transitions

$\text{X}{}_{\mathrm{n+1}}\text{=?(X}{}_{\mathrm{n}}\text{) + ?}{}_{\mathrm{n}}\text{?(X}{}_{\mathrm{n}}\text{)}$

, where f is the recruitment function, and {?_n} is an iid sequence of random shocks. When a positive set-up cost is present an optimal policy is of the (S,s) type. The optimal population level is compared with that of an equivalent deterministic model. Bioeconomic conditions, which imply the optimality of conservation, or extinction are investigated.     

The asymptotic normality of a simple batch epidemic process

A group of n susceptible individuals exposed to a contagious disease isconsidered. It is assumed that at each point in time one or more susceptible individuals can contract the disease. The progress of this simple batch epidemic is modeled by a stochastic process X_n(t), t∈[0, ∞), representing the number of infectiveindividuals at time t. In this paper our analysis is restricted to simple batch epidemics with transition rates given by $\text{[α}{}^2\text{X}{}_{\mathrm{n}}\text{(t){n ?X}{}_{\mathrm{n}}\text{(t) +X}{}_{\mathrm{n}}\text{(0)}]}{}^{\mathrm{<mtext>1</mtext><mtext>2</mtext>}}\text{, t∈[0, ∞), α∈(0, ∞)}$. This class of simple batch epidemics generalizes a model used and motivated by McNeil (1972) to describe simple epidemic situations. It is shown for this class of simple batch epidemics, that X_n(t), with suitable standardization, converges in distribution as n→∞ to a normal random variable for all t∈(0, t₀), and t₀ is evaluated.     

Influence of ionic strength upon the proton inventory for the water-catalyzed hydrolysis of N-acetylbenzotriazole

Proton inventory investigations of the hydrolysis N-acetylbenzotriazole at pH 3.0 (or the equivalent point on the pD rate profile) have been conducted at two different temperatures and at ionic strengths ranging from 0 to 3.0 M. The solvent deuterium isotope effects and proton inventories are remarkably similar over this wide range of conditions. The proton inventories suggest a cyclic transition state involving four protons contributing to the solvent deuterium isotope effect for the water-catalyzed hydrolysis. The hydrolysis data are described by the equation $\text{k}{}_{\mathrm{n}}\text{= k}{}_{\mathrm{<mtext>o</mtext>}}\text{(1 ? n + nπ}{}_{\mathrm{<mtext>a</mtext>}}{}^1\text{)}{}^4$ with $\text{π}{}_{\mathrm{<mtext>a</mtext>}}{}^1\text{～ 0.74}$, where k_o is the observed first-order rate constant in protium oxide, n is the atom fraction of deuterium in the solvent, k_n is the rate constant in a protium oxide-deuterium oxide mixture, and $\text{π}{}_{\mathrm{<mtext>a</mtext>}}{}^1$ is the isotopic fractionation factor.     

Synthesis,enzyme inhibition,and antitumor activity of new 1,4-benzoquinone analogs of coenzyme Q10

A rationale based upon coenzyme Q₁₀ (CoQ₁₀, ubiquinone) for the synthesis of potential antitumor agents constitutes a new approach in the search toward chemotherapy of cancer. The antitumor activities of 38 alkyl-1,4-benzoquinones, analogs of coenzyme Q, 24 of which are new compounds, are described. The 10 best antitumor analogs of CoQ all showed long-term cures of Walker carcinosarcoma 256 in rats. Particularly impressive were the 6-n-octylmercapto-5-chloro-2,3-dimethoxy-1,4-benzoquinone (NSC 252188), which cured six out of six rats with $\text{\%}\text{T}\text{C}\text{= 584 at 3.13 mg/kg}$, 6-phytyl-5-hydroxy-2,3-dimethoxy-1,4-benzoquinone (NSC 277818) (four out of four cures, $\text{\%}\text{T}\text{C}\text{= 923 at 50 mg/kg}$), and 5-phytyl-2,3-dimethoxy-1,4-benzoquinone (NSC 276371) (three out of six cures, $\text{\%}\text{T}\text{C}\text{= 789 at 0.78 mg/kg}$). In general, a 5-chloro or 5-hydroxy group on the quinone nucleus or a side chain with unsaturation and branching, such as the phytyl side chain of NSC 277818 and NSC 276371, seemed to increase antitumor activity. Although a perfect correlation was not to be expected, many of the most potent antitumor analogs were also among the best in vitro inhibitors of the mitochondrial CoQ₁₀-enzymes, succinoxidase, and NAD oxidase.