Influence of the presence of Zymomonas anaerobia on the conversion of cellobiose, glucose, and xylose to ethanol by Clostridium saccharolyticum

To convert sugar mixtures containing cellobiose, glucose, and xylose to ethanol in a single step, the possibility of using a coculture consisting of Clostridium saccharolyticum and Zymomonas anaerobia was studied. In monoculture, C. saccharolyticum utilized all three sugars; however, it preferentially utilized glucose and produced acetic acid in addition to ethanol. The formation of acetic acid from the metabolism of glucose inhibited the growth of C. saccharolyticum and, consequently, the utilization of cellobiose and xylose. In monoculture, Z. anaerobia utilized glucose at a rate of 50 g/L day, but it did not ferment cellobiose or xylose. In coculture, Z. anaerobia converted most of the glucose to ethanol during the lag phase of growth of C. saccharolyticum, which then converted cellobiose and xylose to ethanol. The use of this coculture increased both the rate and the efficiency of the conversion of these three sugars to ethanol, and produced relatively small amounts of acetic acid.     

Catechol-O-methyltransferase: A method for autoradiographic visualization of isozymes in Cellogel

An electrophoretic procedure for separating the molecular forms of catechol-O-methyltransferase in cellulose acetate gel is described; the zones of enzyme activity were revealed by autoradiography. The electrophoretic patterns of the enzyme in several tissues and cell lines derived from four different species are presented.This investigation was supported by Grant 500.6/Ric. 70/1981 from the Italian Ministry of Health and by the Italian Ministry of Education. We are grateful to Dr. M. Castagnola for useful advice and help with thin-layer chromatography.     

Decreased triiodothyronine binding to isolated nuclei from livers of preobese and obese (ob/ob) mice

L-Triiodothyronine (T3) binding to hepatic nuclei from (ob/ob) mice at different ages was examined and compared with that of lean controls. Results showed a significant reduction in T3 binding in liver nuclei of obese mice at all ages studied. The preobese mice at 2 weeks of age had 27.9% fewer receptor sites/mg DNA compared to lean controls, receptor concentration further decreased to 67.7% at 18 weeks of age. Data presented here demonstrates that the impaired triiodothyronine (T3) binding to hepatic nuclei present in older (ob/ob) obese mice is an antecedent to the obesity. This report also helps to explain the poor thermoregulation and low oxygen consumption present during the preobese phase of the postnatal development of these animals.     

云南叶螨属一新种(蜱螨目:叶螨科)

在鉴定云南叶螨标本时,发现叶螨属一新种,现记述如下。模式标本保存于上海农学院。本文量度单位均为微米。 食禾叶螨Tetranychus graminivorus新种(图1—14) 雌螨 体长(包括喙)454,宽298。椭圆形。浅黄绿色。须肢端感器圆柱形,长6.8,     

Electron paramagnetic resonance studies of heme c and its nitrosyl derivative in Vibrio (Achromobacter) fischeri nitrite reductase

Interactions of Vibrio (formerly Achromobacter) fischeri nitrite reductase were studied by electron paramagnetic resonance spectroscopy. The spectrum of the oxidized enzyme showed a number of features which were attributed to two low-spin ferric hemes. These comprised an unusual derivative peak at g = 3.7 and a spectrum at g = 2.88, 2.26, and 1.51. Neither heme was reactive in the oxidized state with the substrate nitrite and with cyanide and azide. When frozen under turnover conditions (i.e., reduction in the presence of excess nitrite), the enzyme showed the spectrum of a nitrosyl heme derivative. The g = 2.88, 2.26, and 1.51 signals reappeared partially on reoxidation by nitrite, indicating that the nitrosyl species which remained arose from the g = 3.7 heme. The nitrosyl derivative showed a 14N nuclear hyperfine splitting, Az = 1.65 mT. The nitrosyl derivative was produced by treatment of the oxidized nitrite reductase with nitric oxide or hydroxylamine. Exchange of nitric oxide between the nitrosyl derivative and NO gas in solution was observed by using the [15N]nitrosyl compound. A possible reaction cycle for the enzyme is discussed, which involves reduction of the enzyme followed by binding of nitrite to one heme and formation of the nitrosyl intermediate.     

Clinical and experimental keratitis caused by the Colletotrichum state of Glomerella cingulata and Acrophialophora fusispora

Two cases of mycotic keratitis caused by the Colletotrichum state of Glomerella cingulata and Acrophialophora fusispora are reported for the first time. Both the isolates produced experimental corneal lesions in rabbit eyes but A. fusispora was more pathogenic. The experimental infection was more severe, with both the fungi, in rabbits pretreated with cortisone as compared with untreated animals. In vitro A. fusispora was most sensitive to miconazole and tolciclate followed by clotrimazole, amphotericin B and lactones while clotrimazole exerted maximum inhibitory effect on Colletotrichum followed by miconazole, lactones, amphotericin B and arnebins. Arnebins and tolciclate were inactive respectively against A. fusispora and Colletotrichum. Of the 3 drugs tested in vivo, against A. fusispora keratitis in rabbit, amphotericin B showed better results than tolciclate and miconazole.     

Fluorescence polarization as a tool to study lectin-sugar interaction

The binding ofRicinus communis agglutinin andAbrus agglutinin to 4-methylumbelliferyl β-D-galactopyranoside was studied by equilibrium dialysis, fluo-rescence quenching and fluorescence polarization. The number of binding sites and the association constant value obtained by fluorescence polarization for bothRicinus communis agglutinin andAbrus agglutinin are in close agreement with those obtained by the other methods. This indicates the potential of ligand-fluorescence polarization measurements in the investigation of lectin-sugar interactions.