Fluorinated carbohydrates. IV. 4-deoxy-4-fluoro-D-galactose

An analytical study has been made of gum specimens from Acacia deanei, A. filicifolia (three specimens), A. leucoclada, A. parramattensis (two specimens), A. parvipinnula, A. silvestris, A. terminalis, and A. trachyphloia, which are species belonging to Series II ({Botryocephalae}) in Bentham's classification of the genus. The three specimens from A. filicifolia are all closely similar, but the specimens from A. parramattensis differ appreciably in parameters other than their sugar ratios. Several of the analytical values reported increase considerably the range of values established so far for Acacia gum exudates. The Botryocephalae species give gum exudates of at least 2 chemically distinct types. Group A species (A. deanei, A. parramattensis, A. parvipinnula, and {A. trachyphloia}) have low galactose-arabinose ratios (<2:1) but have strongly negative rotations, high intrinsic viscosities and molecular weights, and relatively high nitrogen, methoxyl, uronic anhydride, and rhamnose contents. Group B species (A. filicifolia, A. leucoclada, and A. terminalis) have high galactose-arabinose ratios (> ) but low negative or positive rotations, low intrinsic viscosities and molecular weights, and relatively low nitrogen, methoxyl, uronic anhydride, and rhamnose contents.     

Biodegradation of 4-nitrotoluene by Pseudomonas sp. strain 4NT.

A strain of Pseudomonas spp. was isolated from nitrobenzene-contaminated soil on 4-nitrotoluene as the sole source of carbon, nitrogen, and energy. The organism also grew on 4-nitrobenzaldehyde, and 4-nitrobenzoate. 4-Nitrobenzoate and ammonia were detected in the culture fluid of glucose-grown cells after induction with 4-nitrotoluene. Washed suspensions of 4-nitrotoluene- or 4-nitrobenzoate-grown cells oxidized 4-nitrotoluene, 4-nitrobenzaldehyde, 4-nitrobenzyl alcohol, and protocatechuate. Extracts from induced cells contained 4-nitrobenzaldehyde dehydrogenase, 4-nitrobenzyl alcohol dehydrogenase, and protocatechuate 4,5-dioxygenase activities. Under anaerobic conditions, cell extracts converted 4-nitrobenzoate or 4-hydroxylaminobenzoate to protocatechuate. Conversion of 4-nitrobenzoate to protocatechuate required NADPH. These results indicate that 4-nitrotoluene was degraded by an initial oxidation of the methyl group to form 4-nitrobenzyl alcohol, which was converted to 4-nitrobenzoate via 4-nitrobenzaldehyde. The 4-nitrobenzoate was reduced to 4-hydroxylaminobenzoate, which was converted to protocatechuate. A protocatechuate 4,5-dioxygenase catalyzed meta-ring fission of the protocatechuate. The detection of 4-nitrobenzaldehyde and 4-nitrobenzyl alcohol dehydrogenase and 4-nitrotoluene oxygenase activities in 4-nitrobenzoate-grown cells suggests that 4-nitrobenzoate is an inducer of the 4-nitrotoluene degradative pathway.     

4. In-vitro conservation

In-vitro (tissue culture) techniques offer ways of overcoming serious problems in the conservation of crop genetic resources. These primarily involve the use of slow growth and cryopreservation in liquid nitrogen to store germplasm, but there are also important applications in other areas, including germplasm collecting, multiplication and exchange. Slow growth techniques for medium-term storage of cultures are relatively well developed and in-vitro active gene bank establishment is feasible. Cryopreservation for long-term storage is possible for some materials but, in general, requires further research and development. Among the aspects to be examined are the behaviour of different culture systems when exposed to ultralow temperatures, crop-specific requirements and the genetic stability of stored material.     

Partie 4. Rhumatologie

Bone scintigraphy is a nuclear imaging scan using a radiopharmaceutical composed of a bisphosphonate coupled to a radionuclide (technetium 99m). Radiopharmaceutical uptake is particularly important at the level of the bone structures having a strong osteoblastic activity. These uptakes can be due to a benign pathology (fracture, loosening of prosthesis, rheumatic pathologies, etc.) or to a malignant pathology (primary or secondary bone lesion). The high sensitivity of bone scintigraphy makes it particularly interesting at the initial stage of the pathology, especially when X-rays are normal. In addition, its specificity has clearly improved in recent years with the increasingly use of tomoscintigraphy coupled with X-ray scanning (SPECT/CT). We describe the operating principle of bone scintigraphy, normal uptakes with its variants as well as pathological uptake features in traumatic, rheumatic, prosthetic or cancerous pathologies.     

Selective synthesis of 4-methoxyestrogen from 4-hydroxyestrogen.

The introduction of an oxygen atom into the C-6 position of 4-hydroxyestrogen allowed for the selective methylation of the two phenolic hydroxyl groups. When the 6-oxo derivative of 4-hydroxyestrone was benzylated in ethanol, only the 3-monobenzyl ether was obtained without formation of the 4-monobenzyl ether. Moreover, the 6-carbonyl group was further reduced to methylene almost quantitatively in the reaction of 4-acetoxy-6-oxoestrone 3-benzyl ether derivative with sodium borohydride. Therefore, 4-methoxyestrogen was synthesized by essentially combining these two reactions.     

Chloroperoxidase-catalysed oxidation of 4-chloroaniline to 4-chloronitrosobenze.

The incubation of 4-chloroaniline with chloroperoxidase and H2O2 resulted in a rapid formation of 4-chloronitrosobenzene. This enzymic oxidation displayed a pH optimum at 4.4 with a Km of 8.1x10(-4)M and catalytic-centre activity of 312. The initial rate of the reaction was strongly affected by the presence of halide ions. 4-Chlorophenylhydroxylamine was even more rapidly converted into the nitroso compound. A reaction mechanism is proposed on the basis of currently accepted theory for the catalytic action of chloroperoxidae. A noteworthy aspect of this new reaction is the difference in the products previously reported for the action of classical peroxidases on anilines and the single nitroso product resulting from chloroperoxidase oxidation.     

Partial trisomy 4q.

Three new cases (one patient and two sibs) of partial trisomy 4q resulting from a parental translocation are reported. From the literature 22 cases are reviewed and the segregation risk of unbalanced and balanced translocations involving 4q chromosome is discussed.     

4. Preparative Immunoabsorption Electrophoresis

ABSTRACT

A method for separating a component from a mixture of antigens is described. The component, which may be a virus or subfraction of a virus, is isolated by driving the mixture by electrophoresis through a gel containing precipitating antibodies directed against the unwanted components. The method is illustrated by the isolation of hepatitis B antigen from whole serum and by the separation of wild cucumber mosaic virus from a strain of tobacco mosaic virus.     

Multiple-Tailed T4 Bacteriophage.

Smith, Kendall O. (Baylor University College of Medicine, Houston, Tex.), and Melvin Trousdale. Multiple-tailed T4 bacteriophage. J. Bacteriol. 90:796-802. 1965.-T4 phage particles which appeared to have multiple-tails were observed. Experiments were designed to minimize the possibility that superimposed particles might account for this appearance. Double-tailed particles occurred at a frequency as high as 10%. Triple- and quadruple-tailed particles were extremely rare. All attempts to isolate pure lines of multiple-tailed phage have failed. Multiple-tailed phage particles were produced in highest frequency by Escherichia coli cells in the logarithmic growth phase which had been inoculated at a multiplicity of about 2.     

Synthesis of 4'-deoxy-4'-fluorokanamycin A and B.

4'-Deoxy-4'-fluorokanamycins A (17) and B (25) have been prepared through fluorinative ring-opening of the D-galacto-3',4'-oxiranes (8 and 21) derived from kanamycin A and B with potassium hydrogenfluoride in ethane-1,2-diol. The mechanism of preponderant formation of the 4'-deoxy-4'-fluoro-D-gluco (9 and 22) over the 3'-deoxy-3'-fluoro-D-gulo derivatives was discussed. In the synthesis of 25, the unusual 3',6'-epimine (23) was the main product along with the 4'-deoxy-4'-fluoro derivative. The mechanism of this reaction is also discussed. Both 17 and 25 were active against resistant bacteria producing aminoglycoside-adenylylating enzymes for HO-4'.