β-hydroxypropionic acid production by Byssochlamys sp. grown on acrylic acid

A strain of Byssochlamys sp. produced -hydroxypropionic acid when grown on media containing high concentrations of acrylic acid. The maximal production of -hydroxypropionic acid was 4.8% when the initial culture medium contained 7% acrylic acid and 2% glucose, and the initial culture pH was adjusted to 7.0. -Hydroxypropionic acid production from acrylic acid depended greatly on the pH of the culture medium. Calcium hydroxide was the best neutralizer. Correspondence to: K. Takamizawa     

2′-p-Hydroxybenzoyl mussaenosidic acid,a new iridoid glucoside from Vitex negundo.

Ethanolic extract of the leaves of Vitex negundo yielded a new iridoid named 2′-p-hydroxybenzoyl mussaenosidic acid. The structure was established on the basis of chemical and spectral data.     

The amino acid sequence of cytochrome c′ from Alcaligenes sp. N.C.I.B. 11015

The amino acid sequence of the cytochrome c' from Alcaligenes sp. N.C.I.B. 11015 (Iwasaki's ;Pseudomonas denitrificans') has been determined. This organism is the only non-photosynthetic bacterium in which the protein has been found. The protein consists of a single polypeptide chain of 127 residues, with a single haem covalently attached to two cysteines. Unlike normal cytochromes c, the haem attachment site is very close to the C-terminus. The amino acid sequence around the haem attachment site is very similar to that of Chromatium vinosum D cytochrome c'. Detailed evidence for the amino acid sequence of the protein has been deposited as Supplementary Publication SUP 50022 at the British Library (Lending Division), (formerly the National Lending Library for Science and Technology), Boston Spa, Yorks. LS23 7BQ, U.K., from whom copies may be obtained on the terms given in Biochem. J. (1973) 131, 5.     

Terminal-sequence studies of high-molecular-weight ribonucleic acid. The 3′-termini of rabbit reticulocyte ribosomal ribonucleic acid

Sequences of the polynucleotide chains of RNA found in the large and small ribosomal subunits of rabbit reticulocytes have been determined from the 3'-end by use of periodate oxidation and condensation with [(3)H]isoniazid and by stepwise degradation. By these methods the hexanucleotide sequences have been found as -pGpUpUpUpGpU for the 28S RNA and -pGpUpCpGpCpU for the 6S RNA of the large ribosomal subunit and the octanucleotide sequence -pGpApUpCpApUpUpA for the 18S rRNA of the small ribosomal subunit. These sequences are present in at least 70% of all the RNA molecules and are discussed in relation to the specific cleavage of rRNA from its precursors and the role of multiple cistrons for rRNA in the DNA of higher organisms. The feasibility of using the method for longer sequence determinations is discussed.     

Terminal sequence studies of high-molecular-weight ribonucleic acid. The 3′-termini of rabbit globin messenger ribonucleic acid

A study of the relative utilization of thymine and thymidine as precursors for DNA synthesis during normal growth in Bacillus subtilis showed that thymine serves preferentially as a precursor for ;repair' synthesis, whereas thymidine is used preferentially for ;replicative' synthesis. Further, evidence was obtained which suggests that during normal growth both ;replicative' and ;repair' DNA syntheses occur simultaneously. ;Repair' synthesis is distinguished not only on the basis of its preferential utilization of thymine but also by its selective inhibition by caffeine. ;Replicative' synthesis, however, is selectively inhibited by 6-(p-hydroxyphenylazo)-uracil. ;Repair' synthesis would seem to be a ;pre-fork' phenomenon and its inhibition is highly lethal to the cell.     

The lipid–teichoic acid complex in the cytoplasmic membrane of Streptococcus faecalis N.C.I.B. 8191

1. A lipid-teichoic acid complex was isolated from Streptococcus faecalis N.C.I.B. 8191. The covalent nature of the linkage between teichoic acid and lipid was established. 2. The complex exhibits macromolecular properties in solution, and ultracentrifugation studies show that these are due to micelle formation. 3. From chemical studies it is concluded that the teichoic acid is a poly(glycerol phosphate) in which some of the glycerol hydroxyl groups possess kojibiosyl [2-O-alpha-d-glucopyranosyl-(1-->2)-alpha-d- glucopyranosyl] substituents, together with d-alanine ester residues. 4. The lipid is 1-kojibiosyl diglyceride, already known as a membrane component of this organism, with probably a phosphatidyl substituent. The phosphatidyl kojibiosyl diglyceride is attached to the teichoic acid through a phosphodiester linkage, and the chain of the teichoic acid contains 28-35 units. 5. Although the complex represents the whole of the membrane teichoic acid in this organism, only about 12% of the membrane glycolipid is associated with teichoic acid. 6. Two phosphatidyl glycolipids, closely resembling that bearing the teichoic acid, were isolated from the lipids of the organism and were partly characterized.     

Substrate specificity of an α-amino acid ester hydrolase produced by Acetobacter turbidans A.T.C.C. 9325

A partially purified preparation of an alpha-amino acid ester hydrolase was obtained from Acetobacter turbidans A.T.C.C. 9325, which catalyses synthesis of 7-(d-alpha-amino-alpha-phenylacetamido)-3-cephem-3-methyl-4- carboxylic acid (cephalexin) from methyl d-alpha-aminophenylacetate and 7-amino-3-deacetoxycephalosporanic acid. The enzyme preparation catalysed both cephalosprin synthesis from 7-amino-3-deacetoxycephalosporanic acid and suitable amino acid esters (e.g. methyl d-alpha-aminophenylacetate, l-cysteine methyl ester, glycine ethyl ester, d-alanine methyl ester, methyl dl-alpha-aminoiso-butyrate, l-serine methyl ester, d-leucine methyl ester, l-methionine methyl ester) and the hydrolysis of such esters. The substrate specificity of the enzyme preparation for the hydrolysis closely paralleled the acyl-donor specificity for cephalosporin synthesis, even to the reaction rates. Only alpha-amino acid derivatives could act as acyl donors. The hydrogen atom on the alpha-carbon atom was not always required by acyl donors. The hydrolysis rate was markedly diminished by adding 7-amino-3-deacetoxycephalosporanic acid to reaction mixtures, but no effect on the total reaction rate (the hydrolysis rate plus synthesis rate) was observed with various concentrations of 7-amino-3-deacetoxycephalosporanic acid. Both the hydrolytic and the synthetic activities of the enzyme preparation were inhibited by high concentrations of some acyl donors (e.g. methyl d-alpha-aminophenylacetate, ethyl d-alpha-aminophenylacetate). The enzyme preparation hydrolysed alpha-amino acid esters much more easily than alpha-amino acid derivatives with an acid-amide bond.     

Amino acid uptake in the developing chick embryo heart. The effect of insulin on α-aminoisobutyric acid accumulation

1. The uptake of (14)C-labelled alpha-aminoisobutyric acid by 5-day-old chick embryo hearts was investigated in vitro, together with the effect of insulin thereon. 2. At equilibrium the distribution ratio of this amino acid analogue between intracellular and extracellular water attained values greater than unity. Insulin enhanced the rate of alpha-aminoisobutyric acid accumulation and increased the value of its final concentration in the cell water. 3. The rate of alpha-aminoisobutyric acid accumulation and the effect of insulin on it were independent of the presence of glucose in the incubation medium. Bovine and chicken insulin were equally effective, and the action of the hormone was specifically prevented by an anti-insulin serum but not by puromycin. 4. A linear relationship was observed between the intracellular accumulation of the analogue and the logarithm of the insulin concentration in the range 50muunits-100m-units/ml. of incubation medium. 5. Evidence was obtained for the occurrence of two different transport processes for alpha-aminoisobutyric acid in the chick embryo heart: one subject to saturation and one that was not saturated by reasonable concentrations of the analogue. Insulin increased the effectiveness of the saturable component, increasing the maximal velocity of transport without altering the concentration for half-maximal velocity of transport, and decreased the contribution of the non-saturable component.     

Fatty acid biosynthesis in Mycobacterium tuberculosis var. bovis Bacillus Calmette-Guérin. Purification and characterization of a novel fatty acid synthase, mycocerosic acid synthase, which elongates n-fatty acyl-CoA with methylmalonyl-CoA

A crude extract from Mycobacterium tuberculosis var. bovis Bacillus Calmette-Guérin was previously shown to incorporate methylmalonyl-CoA into mycocerosic acids, exemplified by 2,4,6,8-tetramethyloctacosanoic acid, and malonyl-CoA into n-fatty acids (Rainwater D. L., and Kolattukudy, P. E. (1983) J. Biol. Chem. 258, 2979-2985). The presence of several fatty acid synthases with differences in substrate preference and product chain length was detected in the crude extract of M. tuberculosis var. bovis. Among them was a mycocerosic acid synthase which was purified to homogeneity using anion-exchange chromatography, gel filtration, affinity chromatography, and hydroxylapatite chromatography. This fatty acid synthase elongated long-chain fatty acyl-CoA primers using methylmalonyl-CoA and NADPH to produce multimethyl-branched mycocerosic acids. The enzyme was specific for methylmalonyl-CoA and would not incorporate malonyl-CoA into fatty acids. It elongated n-C6 to n-C20 CoA esters to generate primarily the corresponding tetramethyl-branched mycocerosic acids. Exogenous [1-14C]acyl-CoA and trideuteromethylmalonyl-CoA were incorporated into the multimethyl-branched fatty acids. Dodecyl sulfate electrophoresis showed that the enzyme had a molecular weight of 238,000, whereas gel filtration showed a native molecular weight of 490,000, indicating that the enzyme is composed of two monomers of identical molecular weight. The enzyme contained an acyl carrier protein-like segment as indicated by incorporation of [1-14C] pantothenate into the 238-kDa protein and production of 1 mol of taurine/mol of the monomer upon hydrolysis of performic acid-oxidized enzyme. It is concluded that the mycocerosic acid synthase is a multifunctional enzyme similar to the well-characterized multifunctional fatty acid synthases except for the substrate specificity.     

α-N-acetyl-indole-3-acetyl-ε-L-lysine: A metabolite of indole-3-acetic acid from Pseudomonas syringae pv. savastanoi

A product of indole-3-acetic acid (IAA) metabolism having an auxin-like activity has been isolated from liquid cultures of Pseudomonas syringae pv. savastanoi. By spectral data and chemical correlations the compound has been identified as α-N-acetyl-indole-3-acetyl-ε-l-lysine (Ac-IAA-Lys). The IAA-derivative was detected in culture filtrates of oleander strains but not in culture filtrates of olive strains. The physiological effects of Ac-IAA-Lys on hypocotyl elongation in wheat, leaf chlorosis in oleander and bean and the hypertrophic response of potato tuber discs were compared with those of IAA. The results indicated that Ac-IAA-Lys was approximately 60 % less active than IAA.     

НОВЫЙ ВИЗЕЙСКИЙ РОД СПИРИФЕРИД-Grandispirifer gen.nov.

1957年春,地质陈列馆胡承志、牛业华在云南路南老第三系地层中采集了一批哺乳类化石,其中的一部分标本已经研究发表(周,1958)。在这篇报告中,我们又描述了一个完整的雷兽类的头骨,代表一个新的渐新世种。此外,尚有一些未经描述的材料,也将陆续予以描述发表。路南老第三系地层,经过对最近采集的一些哺乳类化石的研究,表明这是到目前为止,代表华南地区最完整的一个老第三系剖面,包括从上始新统至上渐新统间的全套地层,和几个不同时代的脊推动物化石层。进一步的地层调查和化石的系统采集,将对华南老第三系地层的了解和区域对比提供重要的基本研究资料。     

Effects of gibberellic acid and abscisic acid on α-amylase activity and ultrastructure of aleurone cells ofAvena sativa L.

The effects of GA₃ and/or ABA on the α-amylase activity and the ultrastructure of aleurone cells in halves of seeds without embryos (embryo-less half seeds) of oats (Avena sativa L.) were studied. α-Amylase activity was detected by the starch-agar gel method in the aleurone layers of embryo-less half seeds soaked in 1 μM GA₃ solution or 100 μM GA₃+10 μM ABA solution but not in those of seeds soaked in distilled water, 10 μM ABA solution, or 1 μM GA₃+10 μM ABA solution. Ultrastructural examinations of aleurone cells with α-amylase activity showed a decrease in the number of sphaerosomes, the appearance of flattened saccules pressed to the surface of aleurone grains, and the development and transformations of the rER from a slender form to the one with wide inner spaces. In the aleurone cells in which the enzyme activity was not detected, components of the rER showed only slender profiles. The number of sphaerosomes did not decrease, and no flattened saccules appeared in the aleurone cells treated with 10 μM ABA or 1 μM GA₃+10 μM ABA.     

Inhibition of δ-aminolevulinic acid synthetase and δ-aminolevulinic acid dehydrase by L-2-amino-4-methoxy-trans-3-butenoic acid in the rat

The rate limiting enzyme of heme biosynthesis, δ-aminolevulinic acid synthetase (ALA synthetase), and the second enzyme in the heme biosynthetic pathway, δ-aminolevulinic acid dehydrase (ALA dehydrase), were inhibited by the olefinic amino acid L-2-amino-4-methoxy - $\text{trans}$-3-butenoic acid (AMTB). Administration of AMTB (20 mg/kg; i.p.) to rats inhibited ALA synthetase and ALA dehydrase in control animals and in animals with markedly elevated activity of ALA synthetase which resulted from the administration of 3,5-dicarbethoxy-1,4-dimethyl-collidine (DDC, 200 mg/kg, i.p.) or allylisopropylacetamide (200 mg/kg, s.c.). AMTB also blocked the synthesis of rat hepatic porphyrins and inhibited the increase in the urinary excretion of δ-aminolevulinic acid and porphobilinogen following DDC (150 mg/kg, p.o.) administration. Preincubation of AMTB with liver mitochondria or a soluble fraction of liver decreased the activity of mitochondrial ALA synthetase and soluble ALA dehydrase, respectively.     

Biodegradation and metabolic pathway of β-chlorinated aliphatic acid in Bacillus sp. CGMCC no. 4196

In this study, a bacterial Bacillus sp. CGMCC no. 4196 was isolated from mud. This strain exhibited the ability to degrade high concentration of 3-chloropropionate (3-CPA, 120 mM) or 3-chlorobutyrate (30 mM), but not chloroacetate or 2-chloropropionate (2-CPA). The growing cells, resting cells, and cell-free extracts from this bacterium had the capability of 3-CPA degradation. The results indicated that the optimum biocatalyst for 3-CPA biodegradation was the resting cells. The 3-CPA biodegradation pathway was further studied through the metabolites and critical enzymes analysis by HPLC, LC-MS, and colorimetric method. The results demonstrated that the metabolites of 3-CPA were 3-hydroxypropionic acid (3-HP) and malonic acid semialdehyde, and the critical enzymes were 3-CPA dehalogenase and 3-HP dehydroxygenase. Thus, the mechanism of the dehalogenase-catalyzed reaction was inferred as hydrolytic dehalogenation which was coenzyme A-independent and oxygen-independent. Finally, the pathway of β-chlorinated aliphatic acid biodegradation could be concluded as follows: the β-chlorinated acid is first hydrolytically dehalogenated to the β-hydroxyl aliphatic acid, and the hydroxyl aliphatic acid is oxidized to β-carbonyl aliphatic acid by β-hydroxy aliphatic acid dehydroxygenase. It is the first report that 3-HP was produced from 3-CPA by β-chlorinated aliphatic acid dehalogenase.     

δ-Aminolaevulinic acid and amino acid neurotransmitters

Summary The effects of the porphyrin precursor -aminolaevulinic acid (ALA) on -aminobutyric acid (GABA) and L-glutamate transmitter systems was investigated in rat brain. It was found that ALA inhibited GABA and glutamate uptake and stimulated basal efflux of the amino acids in purified nerve endings. These effects were evident only at relatively high concentrations of ALA (at least 100 M). Such concentrations probably do not occur in the nervous systems of patients suffering from acute porphyria. In addition, it was found that ALA inhibited the stimulated release of GABA from nerve endings probably by acting as an agonist at GABA autoreceptors. This effect was found at very low concentrations of ALA (1 M). It is therefore likely that the neuropsychiatric manifestations of the acute porphyric attack are attributable, to some extent, to reduced GABA release at central synapses.     

ZnO–CuxO/polypyrrole nanocomposite modified electrode for simultaneous determination of ascorbic acid,dopamine, and uric acid

Novel zinc oxide (ZnO) nanosheets and copper oxide (Cu_xO, CuO, and Cu₂O) decorated polypyrrole (PPy) nanofibers (ZnO–Cu_xO–PPy) have been successfully fabricated for the simultaneous determination of ascorbic acid (AA), dopamine (DA), and uric acid (UA). The morphology and structure of ZnO–Cu_xO–PPy nanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman spectroscopy. Compared with the bare glassy carbon electrode (GCE), PPy/GCE, Cu_xO–PPy/GCE, and ZnO–PPy/GCE, ZnO–Cu_xO–PPy/GCE exhibits much higher electrocatalytic activities toward the oxidation of AA, DA, and UA with increasing peak currents and decreasing oxidation overpotentials. Cyclic voltammetry (CV) results show that AA, DA, and UA could be detected selectively and sensitively at ZnO–Cu_xO–PPy/GCE with peak-to-peak separation of 150 and 154 mV for AA–DA and DA–UA, respectively. The calibration curves for AA, DA, and UA were obtained in the ranges of 0.2 to 1.0 mM, 0.1 to 130.0 μM, and 0.5 to 70.0 μM, respectively. The lowest detection limits (signal/noise = 3) were 25.0, 0.04, and 0.2 μM for AA, DA, and UA, respectively. With good selectivity and sensitivity, the current method was applied to the determination of DA in injectable medicine and UA in urine samples.     

Terminal-sequence studies of high-molecular-weight ribonucleic acid. The reaction of periodate-oxidized ribonucleosides, 5′-ribonucleotides and ribonucleic acid with isoniazid

1. The reaction products of isoniazid with periodate-oxidized ribonucleosides and 5′-ribonucleotides have been characterized as the monohydrazones. 2. The stability, chromatographic and electrophoretic properties of the hydrazones are described. 3. ³H-labelled isoniazid was shown to react with the 5′-linked terminal adenosine and cytidine groups of periodate-oxidized Escherichia coli transfer RNA. One mole of isoniazid reacts with 27×10³g. of the transfer RNA. 4. One mole of ³H-labelled isoniazid reacts with approx. 10⁶g. of rabbit-reticulocyte ribosomal RNA. After fractionation of the RNA into its two components and treating the fractionated material with pancreatic ribonuclease and ribonuclease T₁ evidence is presented for the existence of two 5′-linked terminal sequences in the 30s fraction and only one sequence in the 17s fraction. 5. The application of this method to determining terminal sequences of high-molecular-weight RNA is discussed.