Biosynthesis of poly-gamma-glutamic acid in plants: transient expression of poly-gamma-glutamate synthetase complex in tobacco leaves

Transient expression of genes coding for the poly-gamma-glutamate (gammaPGA) synthetase system (pgs) was investigated in tobacco plants. Three genes of the pgs, pgsA, pgsB and pgsC, were separately placed under the control of the CaMV 35S promoter and introduced into tobacco leaves via Agrobacterium infection. Synthesized gammaPGA in plant tissues was detected immunologically with mouse anti-gammaPGA antiserum which specifically reacts with gammaPGA on a nitrocellulose membrane. Confirmation of gammaPGA biosynthesis in the transient expression analysis in tobacco tissue indicates that subunits of pgs complex were expressed and reassembled in a functional form.     

Inverted repeat of a large segment unveiled on the right arm of Saccharomyces cerevisiae chromosome II

By means of gene disruption analyses, Saccharomyces cerevisiae strain YPH499 was shown to have two, and only two, copies of ATP3 that encodes the gamma-subunit of H+-dependent ATP synthase and locates on the right arm of chromosome II. Linkage analyses of the two distinguishably marked copies of ATP3 indicated that the distance between them was about 43 cM. Since YBR030W, an ORF proximal to ATP3 by a distance of 17 kbp, was also found to be duplicated, we marked them with two distinguishable nutritional markers, which were also distinguishable from those used for marking the two copies of ATP3, and achieved four-point linkage analyses; CEN2 marked with an appropriate nutritional marker gene was included as a reference point. And, the following linkage map was deduced: CEN2- [11 cM]-YBR030Wa- [8 cM]-ATP3a-[47 cM]-ATP3b- [55 cM]-YBR030Wb. From this map, we suspected that a segment spanning at least YBR030W-ATP3 would be inversely duplicated on the right arm of chromosome II. We then carried out chromosome fragmentation analyses, using several laboratory strains including YPH499, and obtained data in accord with our speculation for all strains, although the distance between the two copies of ATP3 varied from 48 kbp to 192 kbp among the strains examined.     

Kinetics of the reaction between MgNi alloys and H2

The kinetics of the hydriding and dehydriding reaction of Mg₂Ni and Mg-10 wt % Ni was investigated. The reaction rate at various hydride compositions was measured by the pressure change in a constant volume. In the case of Mg₂Ni, at the beginning of the reaction the amount of absorbed/desorbed hydrogen can be expressed by n = k(p₀ – p_eq) (n_s – n₀), where n is the ratio of H to Mg in the solid, p₀ and p_eq are the initial hydrogen pressure of the system and the equilibrium pressure, and n₀ and n_s are the values of n at the start of the reaction and a constant around 2, respectively. After a transient period of approximately 1 min, a diffusion-controlled stage took place as dn/dt = k′(p - p_eq)/t, where p is the pressure at time t. In the case of Mg-10 wt % Ni, throughout a run the absorption/desorption rate was expressed by dn/dt = k″ (p - p_eq)^1.25.     

A thermodynamic study of silica-saturated iron silicate slags in equilibrium with liquid copper

The thermodynamic properties of silica-saturated iron silicate slags in equilibrium with liquid copper have been studied from oxygen partial pressure measurements in the temperature range from 1490 to 1580 K by means of a solid electrolyte galvanic cell. The following cells were used: Pt, Ni-NiO/O⁼/slag-Cu(l), Cr₂O₃, Pt; Pt, Fe-FeO/O⁼/slag-Cu(Fe sat.), Fe. A strong correlation was found between oxygen pressure and the copper content of the slag; the copper content increased from less than 1 pct near iron saturation to about 4 pct at an oxygen partial pressure of 7.2 x 10^?3 Pa. A similar correlation was found between the ferric iron/total iron ratio and the oxygen pressure. The oxygen content in liquid copper decreased with increasing iron content in liquid copper and increased slightly near iron saturation. This behavior could be explained qualitatively by using the standard free energy of formation of FeO and the activities of components.     

Elastic modulus of close-packed randomly oriented Maxwell elements

The paper describes a model composite material in which behavior on the macroscopic scale is related to random orientation of closely packed microscopic Maxwell elements. Equations are developed which yield satisfactory agreement with experimental data from four sources. Although the experimental data came from concrete, the theory is adaptable to other composites.

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Résumé Les réponses des matériaux composites aux stimuli physiques sont souvent reliées aux différentes réponses des matériaux composants par interpolation entre les limites supérieures et inférieures des lois, des mélanges, et que représentent des éléments de Maxwell orientés parallèlement ou perpendiculairement aux lignes de force des stimuli. Les auteurs ont établi des relations qui expriment la réponse élastique d'un élément de Maxwell prismatique à deux phases, incliné selon un angle arbitraire par rapport à l'axe de chargement; puis, par l'emploi d'une fonction de densité probabilistique, ils introduisent une équation simple qui décrirait la réponse élastique d'une couche de ces éléments irrégulièrement orientés et fortement compactés. Cette équation permet des évaluations qui concordent bien avec les valeurs expérimentales du module d'élasticité du béton relevées chez un grand nombre d'auteurs. On s'est servi de l'équation pour estimer la variation du module d'élasticité de la pate de ciment due au vieillissement. Il s'est révélé ainsi que la bonne concordance avec l'expérience se restreignait aux cas où un accroissement du module d'élasticité était associé aux augmentations en quantité d'eau non évaporable. Un accroissement anomal du module d'élasticité se produisait après la fin de l'hydratation des pates de ciment à faible rapport eau/ciment.

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Wideband performance of the injection-limited Gunn diode

A generalised expression of the admittance of diodes with arbitrary field-dependent injection is presented. Using this expression, the negative conductance of the injection-limited Gunn diode offers a wideband performance.     

An iron dioxygenase from Alcaligenes faecalis catalyzing the oxidation of pyruvic oxime to nitrite

An enzyme which participated in the oxidation of hydroxylamine to nitrite from was partially purified Alcaligenes faecalis, and some of its properties were studied. The enzyme oxidized aerobically pyruvic oxime to nitrite in the presence of hydroxylamine or ascorbate. As molecular oxygen equimolar to nitrite formed was consumed in the enzymatic oxidation of pyruvic oxime to nitrite, the enzyme was thought to be a dioxygenase. It was an iron protein, and a reducing reagent was required to keep the iron in the ferrous state for the action of the enzyme.     

Inhibitory effect of Perilla frutescens and its phenolic constituents on cultured murine mesangial cell proliferation

BACKGROUND: Short-stay obstetric stays have been the recent focus of many social and medical debates. We did a retrospective study of a large community teaching hospital's experience in making a safe transition to short-stay obstetrics. METHODS: Over a 10-month period, a multidisciplinary committee developed an intrapartum and postpartum education program to allow short hospital stays after uncomplicated vaginal deliveries. Computerized data were then retrieved on all uncomplicated spontaneous vaginal deliveries (DRG 373) from January 1994 to March 1995. RESULTS: During the study period, 554 women were discharged on the first postpartum day, resulting in three maternal readmissions and nine pediatric readmissions (combined readmission rate of 2.2%). This low readmission rate compared favorably with our experience with 2,563 uncomplicated vaginal deliveries from January 1991 to December 1993, immediately before the institution of the short-stay obstetrics program (combined readmission rate of 3.9%). The average hospital cost for a 1-day stay was $1,714 compared with $2,477 for a 2- to 3-day stay, representing a saving of only 31%. CONCLUSIONS: Early obstetric discharges after an uncomplicated spontaneous vaginal delivery can be safe and effective with appropriate patient selection and support.