Peroxide oxidation of primary alcohols to aldehydes by chloroperoxidase catalysis

Chloroperoxidase catalyzes the peroxidation of primary alcohols, specifically those that are allylic, propargylic, or benzylic. Aldehydes are the products. The reaction dislays appreciable activity throughout the entire pH range investigated, namely pH 3.0–7.0. This enzyme is the only haloperoxidase of four tested capable of carrying out the reaction. These results further establish chloroperoxidase as a unique haloperoxidase.     

Novel Haloperoxidase Reaction: Synthesis of Dihalogenated Products

The enzymatic synthesis of vicinal, dihalogenated products from alkenes and alkynes is described. The enzymatic reaction required an alkene or alkyne, dilute hydrogen peroxide, a haloperoxidase, and molar amounts of halide ions. Vicinal dichloro, dibromo, and diiodo products could be formed. A hydroxyl group on the carbon adjacent to the carbon-carbon double or triple bond lowered the halide ion concentration needed to produce the dihalo product. This reaction offers one explanation for the origin of natural, vicinal, dihalogenated products, such as those found frequently in marine microogranisms.     

The Transport of Carbohydrates by a Bacterial Phosphotransferase System

The components and properties of a phosphoenolpyruvate: glucose phosphotransferase system are reviewed, along with the evidence implicating this system in sugar transport across bacterial membranes. Some possible physiological implications of sugar transport mediated by the phosphotransferase system are also considered.     

A Cytochemical Study of the Stem Cell Concept in Specimens of a Human Ovarian Tumor

The amounts of DNA in interphase nuclei were compared with the amounts of DNA in metaphase and anaphase figures in Feulgen-stained tissue sections of 5 specimens of the human ovarian papillary serous adenocarcinoma. The relative amounts of DNA per cell were determined by cytophotometric measurements of interphase nuclei at a single wavelength and of mitotic figures by the two wavelength method. The 5 specimens conformed to the stem cell concept of cell proliferation since anaphase distributions of amounts of DNA were restricted to a narrow range of DNA values indicating the successful mitosis of a single cell type (stem cell) out of several cell types whose presence were suggested by the wide spread of interphase and metaphase values. In addition, the data indicated that, in some instances, only the amounts of DNA in anaphase figures can reliably identify the stem cell. Changes in the frequency of dividing cells having doubled amounts of DNA, and/or the presence of cells resulting from endoreduplication can distort the interphase distribution of amounts of DNA and thus give rise to a modal DNA interphase value which is not the same as the DNA value of the stem cell (anaphase figures).     

A genetic sexing system to improve the sterile insect technique against the Mediterranean fruit fly

The autosomal recessive allele v wing (v) in the Mediterranean fruit fly, Ceratitis capitata (Wiedemann), produces flies that when reared at 30 degrees C have stubby wings. The mutant was used to construct a translocation-based genetic sexing system in an attempt to improve the efficiency and effectiveness of the sterile insect release method for field control.     

Phosphorylation of Tubulin by Casein Kinase II Regulates Its Binding to a Neuronal Protein (NP185) Associated with Brain Coated Vesicles

We recently described a new protein associated exclusively with neuronal clathrin-coated vesicles (CCVs), and characterized two monoclonal antibodies that react with it (S-8G8 and S-6G7). In this report, the association of neuronal protein of 185 kilodaltons (NP185) with CCV kinases and its interaction with tubulin are described. The affinity of NP185 for tubulin is significantly enhanced when tubulin is phosphorylated by CCV-associated casein kinase II. In contrast, phosphorylation of tubulin by a kinase activity associated with purified brain tubulin decreases its affinity for NP185. Together, these data suggest that the interaction of NP185 with tubulin is modulated by protein phosphorylation. Recent evidence has suggested that tubulin is phosphorylated by casein kinase II during neurite development. The enhanced affinity of NP185 for tubulin phosphorylated by casein kinase II could be important for proper intracellular sorting of this protein in the developing neuron.     

Cloning, sequence analysis, and expression of genes encoding xylan-degrading enzymes from the thermophile "Caldocellum saccharolyticum"

A lambda recombinant bacteriophage coding for xylanase and beta-xylosidase activity has been isolated from a genomic library of the extremely thermophilic anaerobe "Caldocellum saccharolyticum." Partial Sau3AI fragments of the lambda recombinant DNA were ligated into pBR322. A recombinant plasmid with an insertion of ca. 7 kilobases of thermophilic DNA expressing both enzymatic activities was isolated. The location of the genes has been established by analyzing deletion derivatives, and the DNA sequence of 6.067 kilobases of the insert has been determined. Five open reading frames (ORFs) were found, one of which (ORF1; Mr 40,455) appears to code for a xylanase (XynA) which also acts on o-nitrophenyl-beta-D-xylopyranoside. Another, ORF5 (Mr 56,365), codes for a beta-xylosidase (XynB). The xynA gene product shows significant homology with the xylanases from the alkalophilic Bacillus sp. strain C125 and Clostridium thermocellum.     

Am improved procedure for the isolation of chloroplast DNA fromChlamydomonas reinhardtii

The isolation of chloroplast DNA fromChlamydomonas reinhardtii requires the efficient separation of this AT-rich genome from the GC-rich nuclear genome by density-gradient centrifugation. We describe a simple and efficient method for separating these DNA fractions by using a sodium iodide gradient in combination with the DNA-binding dye, bisbenzimide. The yield of chloroplast DNA is close to the theoretical maximum and the DNA is suitable for restriction enzyme analysis and cloning. This method is applicable to the isolation of AT-rich plastid genomes from other organisms and may be appropriate as a general method for separating species of DNA that differ in their AT/GC ratios. An erratum to this article is available at .     

The ultrastructure of the layers enveloping yolk-forming oocytes from Triturus viridescens

Conclusion The peripheral membranous and extracellular layers of oocytes at the onset of yolk formation were studied by electron microscopy. It was shown that three cellular layers are present at this time. The outer or surface epithelium contains typical squamous cells. The middle or theca is the connective tissue layer which contains fibroblasts, blood vessels, and collagen fibers. The inner or follicular epithelium proper consists of compactly arrayed follicle cells that have distinct cell boundaries. Two extracellular layers were observed, a coarse granular homogeneous layer and a dense zona radiata. Macrovilli (0.2 in diameter), extensions from the follicle cells, project through the extracellular layers into the peripheral cytoplasm while more numerous microvilli (0.1 in diameter) project up to the dense matrix of the zona radiata. The plasmolemma separating the peripheral cytoplasm from the follicle cells is completely irregular; it forms microvilli. The relations of the enveloping layers as seen with both light and electron microscopes are discussed.This investigation was supported by a Public Health Service research grant (5803-C3) and research career program award (K-3-5356) from the Division of General Medical Sciences.