Chemical state analysis of sulfur and phosphorus in biological samples by X-ray fluorescence

Double-crystal high-resolution X-ray fluorescence spectroscopy was applied to the chemical state analysis of sulfur and phosphorus in biological samples of leaves and bones. Both S(2-) and S(6+) states are present in all leaves. In plants infected with the mosaic virus, the abundance of S(2-) state was found to be less than normal.Furthermore, the total sulfur content of leaves with the mosaic virus was less than that in normal leaves. From these results we have concluded that the mosaic virus is related to the decrease in cysteine sulfur (S(2-)), which is an essential component in amino acids. Most of the phosphorus in leaves and bones was found to be in P(5+) state. A small amount of P(3+) state, however, was also detected.

Comparison of SR-excited X-ray fluorescence analysis with neutron activation analysis for hair and fiber

Human scalp hair and some kinds of vegetable and animal fibers were analyzed by means of the SR excited X-ray fluorescence method (SRXFA) and the neutron activation method (NAA). Human hair samples collected from five males and five females were washed by the IAEA method prior to analysis. In the SRXFA analysis, samples were excited by monochromated X-rays. Fluorescence X-rays were measured by an Si(Li) detector. The elements detected in all hair samples were S, Ca, Cu, Fe, Zn, Br, and Sr. The elements K, Ti, Cr, Mn, Ni, Se, Hg, and Pb were also detected in several samples. After SRXFA analysis these same samples were analyzed by the NAA method. Elements such as Cu, Zn, and Br were detected by both methods, and their relative concentrations show a good agreement of variation between individuals. However, Pb was only detected by SRXFA, and Na, Au, and Sb were only detected by NAA. Therefore, these two methods are complementary to each other for trace element analysis.

X-ray fluorescence analysis using synchrotron radiation at the photon factory

X-ray fluorescence experiments at the Photon Factory in Japan are described. An energy-dispersive X-ray fluorescence system was combined with various excitation modes, i.e., a continuum and a monochromatic excitation, which consist of a crystal monochromator or a wide band pass monochromator. These excitation modes provide a wide range of band width and photon flux of excitation beams. Minimum detection limits obtained for a thin sample were less than 0.1 ppm and 0.1 pg when there was no line interference. Advantages of using monochromatic excitation are discussed, with emphasis on the possibility of chemical state analysis. Grazing incidence X-ray fluorescence is a technique very appropriate to synchrotron radiation characteristics. Near-surface analysis and trace analysis of solution samples placed on a total reflection support were made. Future plans are discussed, including microbeam analysis, tomography, X-ray excited optical fluorescence, and applications of insertion devices (undulator and wiggler).

[An ultrastructural study of the localization of alkaline phosphatase and Na-K ATPase in the labyrinth from the IUGR rat]

To elucidate the pathogenesis of intrauterine growth retardation (IUGR), the ischemic placentae produced by uterine artery and vein ligation were morphologically and histochemically investigated in rats. In the ischemic condition, fetal growth was remarkably retarded. The labyrinthi were atrophic and trophoblasts were degenerated ultrastructurally in association with mitochondrial swelling, increased microvesicles, dense bodies and fibrin deposition in the dilated intercellular spaces. Alkaline phosphatase and Na-K ATPase were localized on the plasma membrane in control rats. Na-K ATPase activity was observed in the basal side of cytotrophoblasts. However, the enzyme activities were decreased in the ischemic condition. The reaction products of horseradish peroxidase were present in the dilated intercellular spaces and increased cytoplasmic vesicles. These results suggest that in the ischemic condition, IUGR might be induced by the plasma membrane dysfunction following decreased enzyme activities and irregular distribution of horseradish peroxidase.

[Surgical treatment of colon cancer]

The treatment of early colon cancer limited lamina propria mucosa is endoscopic polypectomy. If invasion into the submucosal layer is present, usual colectomy with regional lymph adenectomy is indicated. Colon cancer without distant metastasis is treated by colectomy with regional lymph adenectomy. Right hemicolectomy, transverse colectomy, left hemicolectomy, and sigmoidectomy are indicated according to the location of the cancer. Five years survival rate for curative resection in 96 personal cases was 80.8%. Palliative resection was available to prolong the survival time. Mean survival time after palliative resection was 14 months, but in unresectable case it was 4 months.

Gene transfer into intact plant cells by electroinjection through cell walls and membranes

Tobacco mosaic virus (TMV) RNA was introduced directly into mesophyll cells of Nicotiana tabacum var. Samsun using electric-field pulses (electroinjection). The injected gene was successfully expressed in the recipient cells as judged by the assay for the virus coat protein using immunofluorescence and by the virus infectivity assay of the homogenate of the electroinjected cells for local lesions on tobacco leaves. As much as 50% of the cells that survived 24 days after electroinjection showed immunofluorescent specks.

A signal sequence mutant defective in export of ribose-binding protein and a corresponding pseudorevertant isolated without imposed selection

Ribose-binding protein is exported to the periplasmic compartment of Escherichia coli by a process that involves proteolytic cleavage of an amino-terminal extension of amino acids from the precursor form of the protein. In a collection of mutants isolated as defective in the Rbs transport system, a strain was identified that contained only precursor ribose-binding protein, none of which was exported to its normal location in the periplasm. The mutated rbsB contained a base substitution that results in a change of leucine to a proline at position-17 in the signal sequence. A pseudorevertant of the mutant contained proteolytically processed, active ribose-binding protein in the periplasm. The pseudorevertant rbsB carried a second mutation: serine at position-15 in the signal sequence was changed to phenylalanine. Isolation of a signal sequence mutant and a corresponding pseudorevertant without specific selection or site-directed mutagenesis emphasizes the possibility of obtaining export mutants without the use of procedures that could bias or limit the range of mutations found. Explanation of the extreme phenotype of the mutant and the effective correction of that phenotype in the pseudorevertant requires extension of current notions of critical features of signal sequences.

Molecular cloning and characterization of genes required for ribose transport and utilization in Escherichia coli K-12

We isolated spontaneous and transposon insertion mutants of Escherichia coli K-12 that were specifically defective in utilization or in high-affinity transport of D-ribose (or in both). Cotransduction studies located all of the mutations near ilv, at the same position as previously identified mutations causing defects in ribokinase ( rbsK ) or ribose transport ( rbsP ). Plasmids that complemented the rbs mutations were isolated from the collection of ColE1 hybrid plasmids constructed by Clarke and Carbon. Analysis of those plasmids as well as of fragments cloned into pBR322 and pACYC184 allowed definition of the rbs region. Products of rbs genes were identified by examination of the proteins produced in minicells containing various rbs plasmids. We identified four rbs genes: rbsB , which codes for the 29-kilodalton ribose-binding protein; rbsK , which codes for the 34-kilodalton ribokinase ; rbsA , which codes for a 50-kilodalton protein required for high-affinity transport; and rbsC , which codes for a 27-kilodalton protein likely to be a transport system component. Our studies showed that these genes are transcribed from a common promoter in the order rbsA rbsC rbsB rbsK . It appears that the high-affinity transport system for ribose consists of the three components, ribose-binding protein, the 50-kilodalton RbsA protein, and the 27-kilodalton RbsC protein, although a fourth, unidentified component could exist. Mutants defective in this transport system, but normal for ribokinase , are able to grow normally on high concentrations of the sugar, indicating that there is at least a second, low-affinity transport system for ribose in E. coli K-12.

Contrast echocardiography in detection of portopulmonary venous anastomosis

Portopulmonary venous anastomosis is a potential channel for systemic arterial embolization during embolization procedures for bleeding esophageal varices. To document the presence of such anastomoses, 15 patients with esophageal varices were studied by real-time contrast echocardiography combined with transhepatic cineportography. Cinefluorographic technique, which was applied for this purpose, occasionally failed to demonstrate the dynamic events in the left atrium because of rapid dilution of contrast medium. Echocardiography after the injection of dextrose solution into the gastric coronary vein allowed two-dimensional real-time images of contrast echoes in the left cardiac chambers. By combining these two methods, more reliable diagnostic information was obtained in five of the 15 patients studied.

Investigation of an intracellular hemolytic agent of Vibrio parahaemolyticus. Lipid fraction of dried cells

The dried cells of two strains of Vibrio parahaemolyticus were fractionated by extracting first with water and then with organic solvents. The hemolytic activity of the fractions was determined, and some of them were assayed for their effect in mice. The hemolytic agent present in the water-insoluble fraction was extractable in organic solvents such as 70% aqueous ethanol, chloroform-methanol-water (1:2:0.8) and acetone. The extracts showed no toxic effect in mice after intraperitoneal inoculation. No hemolytic activity was observed in the remaining cell residue, which bore the toxicity.