Primary structures of and genes for new ribosomal proteins A and B in Escherichia coli

We determined the partial primary structures of and identified the genes for new basic proteins A and B in Escherichia coli ribosomal 50S subunits, found by means of an improved two-dimensional gel electrophoresis method. The sequence up to the 17th amino acid of protein B was in agreement with that of the X gene in the spc operon. The gene for protein A was searched for in the GenBank data base using the sequence up to the 35th amino acid, and was found at a locus between infC and rplT. The base sequence indicated that protein A contained 64 amino acids and had a molecular weight of 6,984. We conclude that proteins A and B are intrinsic ribosomal proteins, and propose calling their genes, rpmI and rpmJ, respectively.     

Hypersomatostatinemia in chronic renal failure

Plasma concentrations of somatostatin-like immunoreactivity (SLI) were determined in uremic patients on maintenance hemodialysis. Plasma SLI levels were significantly (p less than 0.001) elevated in 26 diabetic uremic patients (67.1 +/- 6.8 pg/ml, mean +/- SE) and in 24 non-diabetic uremic patients (43.5 +/- 7.2 pg/ml), when compared with 60 healthy subjects (5.0 +/- 0.7 pg/ml). Paired pooled plasma from uremic patients before and after hemodialysis was subjected to a reverse-phase octadecasilyl-silica (C-18) cartridge and then the extract was gel filtered on a Sephadex G-25 column (1.6 X 90 cm). Both elution profiles showed two peaks of SLI which coeluted with synthetic somatostatin (SS)-28 and SS-14 markers, respectively. The SS-28-like immunoreactivity (LI) peak, which was estimated by using SS-14 as a reference standard, was 3-fold larger than that for SS-14 LI. On the basis of immunoequivalency of the two components in the present assay, SS-28 LI constitutes approximately 75% of circulating somatostatin. In conclusion, plasma SLI is substantially high in uremic patients of both diabetic and non-diabetic etiology and the SS-28 is a predominant form of circulating SLI in these patients, probably, in part, for a lower clearance of this molecule.     

Characterization of neutral glycosphingolipids from porcine erythrocyte membranes

1. Six neutral GSL fractions were purified from porcine erythrocyte membranes. 2. They were identified to be LacCer (14% of total neutral GSLs), 2-hydroxy acid-rich and -poor Gb3Cer (3 and 7%, respectively) and Gb4Cer (71%) by means of NMR spectrometry. 3. Monohexosylceramides (5%) were composed of GlcCer and GalCer with near amount. 4. All these GSL classes contained a high concentration (more than 20% of total acids in each class) of 2-hydroxy fatty acids. 5. GalCer and GlcCer contained considerable amounts of C16- and C18-acids, and of C18-phytosphingosine, whereas C24-acids and C18-sphingosine were predominant in the other GSLs. 6. A minor GSL fraction (less than 1% of total neutral GSLs) which migrated more slowly than Gb5Cer on a thin layer plate and composed of several GSL components contained L-fucose.     

Confined lateral diffusion of membrane receptors as studied by single particle tracking (nanovid microscopy). Effects of calcium-induced differentiation in cultured epithelial cells.

The movements of E-cadherin, epidermal growth factor receptor, and transferrin receptor in the plasma membrane of a cultured mouse keratinocyte cell line were studied using both single particle tracking (SPT; nanovid microscopy) and fluorescence photobleaching recovery (FPR). In the SPT technique, the receptor molecules are labeled with 40 nm-phi colloidal gold particles, and their movements are followed by video-enhanced differential interference contrast microscopy at a temporal resolution of 33 ms and at a nanometer-level spatial precision. The trajectories of the receptor molecules obtained by SPT were analyzed by developing a method that is based on the plot of the mean-square displacement against time. Four characteristic types of motion were observed: (a) stationary mode, in which the microscopic diffusion coefficient is less than 4.6 x 10(-12) cm2/s; (b) simple Brownian diffusion mode; (c) directed diffusion mode, in which unidirectional movements are superimposed on random motion; and (d) confined diffusion mode, in which particles undergoing Brownian diffusion (microscopic diffusion coefficient between 4.6 x 10(-12) and 1 x 10(-9) cm2/s) are confined within a limited area, probably by the membrane-associated cytoskeleton network. Comparison of these data obtained by SPT with those obtained by FPR suggests that the plasma membrane is compartmentalized into many small domains 300-600 nm in diameter (0.04-0.24 microns2 in area), in which receptor molecules are confined in the time scale of 3-30 s, and that the long-range diffusion observed by FPR can occur by successive movements of the receptors to adjacent compartments. Calcium-induced differentiation decreases the sum of the percentages of molecules in the directed diffusion and the stationary modes outside of the cell-cell contact regions on the cell surface (which is proposed to be the percentage of E-cadherin bound to the cytoskeleton/membrane-skeleton), from approximately 60% to 8% (low- and high-calcium mediums, respectively).     

Varicella infection in a children's hospital: prevention by vaccine and an episode of airborne transmission

Varicella vaccine was used safely and effectively for preventing ward infection with varicella. Ward infection was experienced 34 times in 5 years between 1977 and 1982. During these ward infections, varicella developed in 4 of 142 patients who received vaccine, 21 of 47 patients who did not receive vaccine and 1 of 9 who received transfusion with vaccine-boostered blood. Of the 142 vaccinated patients, the four in whom varicella developed showed symptoms 3 to 10 days after vaccination, indicating that vaccination had been too late. Details of a ward infection with varicella by airborne transmission and its prevention by vaccination are presented.     

Coordinate expression of Escherichia coli dnaA and dnaN genes

Summary The defects of temperature-sensitive dnaA and dnaN mutants of Escherichia coli are complemented by a recombinant lambda phage, which carries the bacterial DNA segment composed of two EcoRI segments of 1.0 and 3.3 kilobases. Derivatives of the phage, which have an insertion segment of Tn3 in the dnaA gene, are much less active in expressing the dnaN gene function than the parent phage. The dnaN gene activity was determined as the efficiency of superinfecting phage to suppress loss of the viability of lysogenic dnaN59 cells at the nonpermissive temperature. Deletions that include the end of the dnaA gene distal to the dnaN gene also reduce the expression of the dnaN gene fuction. Deletion and insertion in the dnaN gene do not affect the expression of the dnaA gene function. The expression of the dnaN gene function by the dnaA ^- dnaN ⁺ phages remains weak upon simultaneous infection with dnaA ⁺ dnaN ^- phages. Thus the insertion and deletion in the dnaA gene influence in cis the expression of the dnaN gene. We propose that the dnaA and dnaN genes constitute an operon, where the former is upstream to the latter.     

Cysteine 295 indirectly affects Ni coordination of carbon monoxide dehydrogenase-II C-cluster

A unique [Ni–Fe–S] cluster (C-cluster) constitutes the active center of Ni-containing carbon monoxide dehydrogenases (CODHs). His²⁶¹, which coordinates one of the Fe atoms with Cys²⁹⁵, is suggested to be the only residue required for Ni coordination in the C-cluster. To evaluate the role of Cys²⁹⁵, we constructed CODH-II variants. Ala substitution for the Cys²⁹⁵ substitution resulted in the decrease of Ni content and didn’t result in major change of Fe content. In addition, the substitution had no effect on the ability to assemble a full complement of [Fe–S] clusters. This strongly suggests Cys²⁹⁵ indirectly and His²⁶¹ together affect Ni-coordination in the C-cluster.     

Validity of NIR spectroscopy for quantitatively measuring muscle oxidative metabolic rate in exercise

The purpose of this studywas to examine the validity of the quantitative measurement of muscleoxidative metabolism in exercise by near-infrared continuous-wavespectroscopy (NIRcws). Twelve male subjects performed two bouts ofdynamic handgrip exercise, once for the NIRcws measurement and once forthe ³¹P-magnetic resonance spectroscopy (MRS) measurementas a standard measure. The resting muscle metabolic rate (RMRmus) wasindependently measured by ³¹P-MRS during 15 min of arterialocclusion at rest. During the first exercise bout, the quantitativevalue of muscle oxidative metabolic rate at 30 s postexercisewas evaluated from the ratio of the rate of oxyhemoglobin/myoglobindecline measured by NIRcws during arterial occlusion 30 s afterexercise and the rate at rest. Therefore, the absolute values of muscleoxidative metabolic rate at 30 s after exercise[O_2NIR(30)] wascalculated from this ratio multiplied by RMRmus. During the secondexercise bout, creatine phosphate (PCr) resynthesis rate was measuredby ³¹P-MRS at 30 s postexercise[Q₍₃₀₎] under the same conditions but without arterial occlusion postexercise. To determine the validity ofNIRcws, O_2NIR(30) wascompared with Q₍₃₀₎. There was a significant correlation betweenO_2NIR(30), which rangedbetween 0.018 and 0.187 mM ATP/s, and Q₍₃₀₎,which ranged between 0.041 and 0.209 mM ATP/s (r = 0.965, P < 0.001). This result supports theapplication of NIRcws to quantitatively evaluate muscle oxidativemetabolic rate in exercise.