Correction to: Metabolic pathway of 6-aminohexanoate in the nylon oligomer-degrading bacterium Arthrobacter sp. KI72: identification of the enzymes responsible for the conversion of 6-aminohexanoate to adipate

Applied Microbiology and Biotechnology - The original publication of this paper contains mistakes for Tables 1 and 2 legends as well as the sublabels in Figs. 2, 4, 5, 6, and 7.     

Insolubilization of exogenous primer dextran with 1,3-α-d-glucan synthase from Streptococcus mutans

Abstract The water-insolubilization mechanism of exogenous primer dextran with 1,3-α- d -glucan synthase (EC 2.4.1.-) from Streptococcus mutans was studied. The 1,3-α- d -glucan synthase solution, containing sucrose and exogenous primer dextran, was incubated briefly. Water-insoluble glucan was synthesized. At the same time, water-soluble glucan, mainly derived from exogenous primer dextran, decreased. Linkage analysis data of glucan produced revealed that 1,3-α- d -glucoside bonds increased. Exogenous primer dextran was changed by the action of 1,3-α- d -glucan synthase to water-insoluble glucan. The results suggest that in a short-term reaction system of outside primer-insertion type, the 1,6-α- d -glucoside bond forms the main chain of water-insoluble glucan.     

Immunological properties of the primer-independent glucosyltransferase of Streptococcus mutans serotypes d and g

Streptococcus mutans serotype g secretes at least three kinds of glucosyltransferase with different enzymological and immunological properties. One of them is a primer-independent enzyme and seems to be the source of primer for the others, both of which are primer-dependent enzymes. Recently, we purified the primer-independent enzyme, the third glucosyltransferase in this group from S. mutans strain AHT-k serotype g. In the present study, we examined the specificity of the antiserum against the primer-independent glucosyltransferase using extracellular culture-conditioned fluids of many strains of the various serotypes of S. mutans. The antiserum cross-reacted with the extracellular culture fluids from strains of serotypes d and a, in addition to serotype g, but not with those of other serotypes, indicating that the primer-independent glucosyltransferase is secreted by the S. sobrinus and S. cricetus, but not by S. mutans and S. rattus. The antiserum did not completely inhibit the activity of the enzyme, even at more than twofold antibody excess, determined by indirect precipitation with immobilized staphylococcal protein A.     

Expression of a Human Cocaine-Sensitive Dopamine Transporter in Xenopus laevis Oocytes

The human dopamine transporter was expressed in Xenopus laevis oocytes following injection of mRNA isolated from human brain substantia nigra. The specific accumulation of [3H]dopamine into these oocytes was time and Na+ dependent. Furthermore, [3H]dopamine accumulation was prevented by coincubation of oocytes with dopamine (100 microM) or with the dopamine uptake inhibitors GBR 12909 (1 microM) or cocaine (3 microM). In contrast, oocyte injection of mRNA isolated from human globus pallidus, an area devoid of dopamine neuron perikarya, did not elicit expression of the dopamine transporter. Oocyte expression of the human dopamine transporter can be used for the further characterization and cloning of this low-abundance membrane protein.     

Differential regulation of phenylalanine ammonia-lyase genes during anthocyanin synthesis and by transfer effect in carrot cell suspension cultures

Phenylalanine ammonia-lyase (PAL; EC 4.3.1.5) catalyses the first step in the phenylpropanoid pathway and is induced during differentiation and by various stimuli. In carrot ( Daucus carota L. cv. Kurodagasun) suspension culture cells, PAL is slowly induced during anthocyanin synthesis which occurs in a medium lacking 2,4-dichlo-rophenoxyacetic acid and is also induced rapidly and transiently by transferring and diluting cells to fresh medium. Analyses of nucleotide sequences derived from PAL cDNAs revealed that the PAL mRNAs induced by transfer were transcribed from different carrot PAL genes than the PAL mRNAs induced during anthocyanin synthesis. Northern blotting using probes derived from 3'non-coding regions for PAL cDNAs confirmed that different PAL genes were induced during anthocyanin synthesis and after transfer. Induction of different PAL genes occurs in response to differences in the induction trigger.     

Quantitative Determination of Changes in the Number and Size of Chloroplasts in Naturally Senescing Leaves of Rice Seedlings

Changes in the number and size of chloroplasts in senescingleaves of rice seedlings were determined. The method employedinvolves electron microscopic examination of large numbers ofcells and chloroplasts in the mesophyll of leaves at differentstages of senescence with the aid of a microcomputer. Analysisshowed that, once leaves had been fully expanded, the numberand size of the mesophyll cells remained unaltered throughoutthe course of senescence. By contrast, the quantity of chloroplastspresent in leaves decreased with advancing senescence. Whencompared with the newly expanded 6th leaves, the chloroplastnumber per unit area of mesophyll section was reduced by 40%and the mean cross section area of chloroplasts by 23% in theoldest leaves (3rd leaves) of seedlings. Chloroplasts occupied33% of the mesophyll section area in the 6th leaves and thepercentage decreased slightly in the 5th leaves and markedlyin lower leaves to reach 17% in the 3rd leaves. The rate ofoxygen evolution decreased approximately in parallel to thedecline in the chloroplast content. Thus, sequential decreasein the amount of chloroplasts is a main cause of loss of photosynthesisduring foliar senescence of rice seedlings. (Received May 31, 1989; Accepted October 17, 1989)     

Evaluation of basic procedures for adoptive immunotherapy for gastric cancer

Peripheral blood lymphocytes (PBL) of gastric cancer patients in advanced stages showed lymphokine activated killer (LAK) activities comparable to those of healthy donors, suggesting potential applicability of LAK cells induced from PBL stimulated with recombinant interleukin-2 (rIL-2) in adoptive immunotherapy (AIT) for gastric cancer. In order to generate a large number of LAK cells from PBL, lymphocytes were cultured with both rIL-2 and phytohemagglutinin (PHA). In this culture, the numbers of cells increased to a greater extent than those in culture with rIL-2 alone but cytotoxic activity did not augment, thus suggesting that this procedure would not afford sufficient clinical effects. On the other hand, a large number of LAK cells with high anti-tumor activities were efficiently induced from spleen cells of the patients by culture of rIL-2; hence clinical usefulness of these LAK cells is anticipated. In regional lymph node lymphocytes (RLNL) cultured with rIL-2, the cytotoxic activities were lower than in those induced in PBL, and a characteristic increase of CD8 + CD11 + suppressor T cells was observed after incubation with rIL-2. Nevertheless, an increase of CD4 + 4B4⁺ helper inducer T cells was also observed in RLNL after the culture with rIL-2. Furthermore, high cytotoxic activities were induced in RLNL in some cases in which metastasis to the regional lymph nodes was not detected. When gastric cancer patients were pretreated with biological response modifiers (BRM), especially with Lentinan, LAK cells from PBL showed higher NK and LAK activities as compared with those of patients without BRM pretreatment.This work was partly supported by a grant from Hokkoku Cancer Research Foundation.     

Prophylactic effect of bestatin on the onset of invasive mole — clinical and fundamental studies

This study was performed to determine whether bestatin (Ubenimex) has clinical prophylactic effects on the onset of invasive mole and a direct inhibitory effect on the growth of hydatidiform molar cells. A total of 49 patients with hydatidiform mole treated at Nagoya University Hospital from 1984 to 1990 were randomly divided into two groups, a bestatin administered-group and a bestatin non-administered group. Patients in the bestatin group were given 30 mg of bestatin orally and daily for three months just after their molar deliveries. There was no significant difference in age, gravidity, parity and gestational weeks between the two groups. There was also no significant difference in the duration of human chorionic gonadotropin (hCG) negative conversion in patients without invasive mole between the two groups. However, the incidence of invasive mole in the bestatin group (2/25, 8%) was significantly lower than that of the non-bestatin group (7/24, 29.2%). Nevertheless, there was no significant difference between the two groups in such immunological parameters as PHA skin test, PPD skin test, PHA stimulation index (PHA-SI), white blood cell (WBC) count lymphocytes % per WBC, OKT 3% per lymphocytes, OKT 4% per lymphocytes, OKT4/OKT8 and Leu 11% per lymphocytes. In vitro studies were performed with primary cultured hydatidiform moles. The result was that bestatin inhibited the secretion of hCG and³H-thymidine uptake of hydatidiform molar cells. Thus, a possibility was suggested that bestatin directly inhibits the growth of hydatidiform molar cells and prevents the onset of invasive mole.     

A novel glucosyltransferase from Streptococcus mutans produces oligo-isomaltosaccharides

Streptococcus mutans secretes a sucrose-independent branalphang enzyme that utilizes isomaltosaccharides as donors for branalphang formation on dextran. Although the branching enzyme is necessary for the formation of extracellular polysaccharide complexes, the source of the donor for the enzyme is unknown. In this study, we purified a novel glucosyltransferase from S. mutans and characterized its properties. The glucosyltransferase was primer independent 1,6-alpha-D-glucan synthase, which produced oligo-isomaltosaccharides. The enzyme was thought to be a source of donor for the branching enzyme in S. mutans.     

Comparative study of the antitumor effect of two types of murine recombinant interferons, (β) and (γ), against B16-F10 melanoma

Summary A comparative study of the antitumor effect of murine recombinant interferon() Mu-rIFN() and murine recombinant interferon() Mu-rIFN() on B16-F10 melanoma was conducted. Administration of Mu-rIFN() i.p. into C57BL/6 mice on days 1 to 7 produced a higher suppressive effect than Mu-rIFN() both on the growth of s.c. implanted tumor and on the formation of artificial pulmonary metastasis. Pharmacokinetic study of Mu-rIFN() demonstrated that high plasma levels were retained for a long time. In clonogenic assay, Mu-rIFN() at 1000 units/ml showed about 80% inhibition of colonies of B16-F10 melanoma. However, Mu-rIFN() hardly inhibited the colonies, even at 1000 units/ml. Augmentation of natural killer (NK) cytotoxicity was much greater with Mu-rIFN() than Mu-rIFN(), whereas Mu-rIFN() enhanced the cytotoxicity of peritoneal macrophages more strongly than Mu-rIFN(). Injection of Mu-rIFN() i.p. 1 day before tumor challenge also inhibited the formation of pulmonary metastasis of B16-F10 melanoma. However, pretreatment of mice with carrageenan significantly suppressed the inhibitory effect of Mu-rIFN(). From these results, it is suggested that the inhibitory effect of Mu-rIFN() on the tumor growth and metastases of B16-F10 melanoma is mediated partly by direct antitumor effect and partly by the activation of macrophages, and that the augmentation of NK activity contributes mainly to the antitumor effect of Mu-rIFN().