Preparation of optically active trifluoromethylated (3′-indolyl) thiacarboxylic acids, novel plant growth regulators, through lipase-catalyzed enantioselective hydrolysis

Among a variety of lipases tested, that obtained from Candida antarctica (SP 435) induced enantioselective hydrolysis of trifluoroethyl 5,5,5-trifluoro-4-(3'-indolyl)-3-thiapentanoate (1c). The selectivity could be increased by optimizing the reaction conditions. Thus, good selectivity was achieved (E = 37) in a buffer containing 10% dichloroethane. In order to improve the optical yields, a sequential kinetic resolution was utilized for the preparative-scale enantioselective hydrolysis of 1c using SP 435. Hydrolysis of trifluoroethyl 6,6,6-trifluoro-5-(3'-indolyl)-4-thiahexanoate (2c) with the lipase of Pseudomonas aeruginosa (LIP) in a buffer containing 20% tert-amyl alcohol at 25 degrees C gave excellent selectivity (E=357).

Production of gamma-aminobutyric acid by cheese starters during cheese ripening

Nine mixed-strain starters were examined for their abilities to produce gamma-aminobutyric acid. Six commercial starters were found to produce gamma-aminobutyric acid in a skim milk culture. The bacterium that produced gamma-aminobutyric acid was isolated from the mixed-strain starters, identified as citrate-utilizing Lactococcus lactis ssp. lactis (formerly L. lactis ssp. lactis biovar diacetylactis) and designated as strain 01-7. A cell extract showed glutamate decarboxylase activity, for which the optimum pH was 4.7. In pH-controlled cultivation, gamma-aminobutyric acid was generated at pH 5.0 but not above pH 5.5. Cheeses were prepared experimentally using strain 01-7 to determine the relationship between the pH values and the production of gamma-aminobutyric acid during cheese ripening. gamma-Aminobutyric acid increased linearly in the experimental cheeses as the pH of the cheese decreased. Based on these results, gamma-aminobutyric acid was concluded to be produced by the cheese starters during ripening.

Effects of cis-diamminedichloroplatinum(II) on Escherichia coli and bacteriophage systems

The effects of cis-diamminedichloroplatinum(II) (cisplatin) on Escherichia coli cells and bacteriophages were investigated. The bacteriocidal effect of cisplatin was stronger on uvrA or recA mutants than on wild type cells. The drug, like UV, induced prophage development in lysogenic bacteria. Host cell reactivation of alpha3 replicative form (RF) I DNA treated with cisplatin in vitro was more efficient in wild type or recA cells than in uvrA host. When wild type cells were exposed to cisplatin, decay of the host's capacity to sustain the viral multiplication proceeded nearly in parallel with the loss of colony-forming ability, whereas the capacity of uvrA mutant was much more resistant to the drug, as compared with the viability. In the DNA preparation from cisplatin-treated alpha3-infected wild type cells, RF II was deficient, but the RF I molecules extracted from the cells were moderately infective. The microvirid gene A protein, required for RF I-->RF II conversion, was hardly detectable in wild type cells exposed to cisplatin. The possible relationship between uvr+-dependent repair and synthesis of the viral protein is discussed.

Urinary metabolites of valproic acid in epileptic patients

The urinary excretion of valproic acid (VPA) and its metabolites (3-keto VPA, 3-OH VPA, and VPA-glucuronide) in 6 epileptic patients was studied using gas chromatography-mass spectrometry. The amount of VPA and 3-OH VPA excreted in the urine was low (0.1-0.5% of the dose of VPA and 0.6-1.5% of the dose of 3-OH administered). The amount of 3-keto VPA and glucuronide (VPA-Glu) excreted was marked (5.8-26.2% and 13.1-88.7% of the dose of VPA administered, respectively). The urinary excretion of VPA and its metabolites by patients who have taken a normal amount of a VPA preparation was almost the same as that of healthy volunteers. Two epileptic patients who took a large amount of the VPA preparation showed a high excretion of VPA-Glu without an increase in their plasma VPA-Glu.

Effects of synthetic hydroxy isothiocyanates on microbial systems

Hydroxy isothiocyanates (ITCs), including some new derivatives of naturally occurring compounds, were synthesized and their minimum inhibitory, minimum fungicidal, and minimum bactericidal concentrations for Aspergillus niger, Aspergillus fumigatus, Staphylococcus aureus, and Escherichia coli were estimated. These compounds were strongly antimicrobial; for example, 2-(4-hydroxyphenyl) ethyl ITC inhibited growth of all strains examined at concentrations of 7.8 to 15.6 micrograms/ml. The ATP concentration in E. coli was markedly reduced when cells were treated with 2-(4-hydroxyphenyl)ethyl ITC. Inhibition of the growth of E. coli by 2-(4-hydroxyphenyl)ethyl ITC was decreased in the presence of cysteine. Streptolysin S production in washed cells of Streptococcus equisimilis was extremely sensitive to this ITC derivative and this inhibition also was counteracted by cysteine. The results showed that the ITC compounds had antimicrobial effects by blocking sulfhydryl groups.

Mouse germinal center B cells with the xid mutation retain responsiveness to antimouse CD40 antibodies but diminish IL-5 responsiveness

The germinal center (GC) develops in secondary lymphoid tissues in response to thymus-dependent (TD) antigens. To investigate the molecular mechanism of B cell differentiation in GC, we enriched GC B cells from spleen of TD antigen-immunized wild-type and X-linked immunodeficient (XID) mice, and examined the differentiation of GC B cells into antigen-specific IgG1 antibody-forming cells (AFC) in response to anti-CD40 mAb and cytokines. A significant proportion of freshly purified GC B cells expressed receptors for IL-4 and IL-5. Anti-CD40 mAb sustained the viability of GC B cells and IL-4 co-operated with anti-CD40 mAb for further enhancement of the cell viability. Anti-CD40 mAb and IL-4 were essential for inducing differentiation of GC B cells into antigen-specific IgG1-AFC and IL-5 efficiently enhanced their differentiation. GC B cells with the xid mutation responded for proliferation to CD40 ligation to a lesser extent and for the IgG1-AFC response to anti-CD40 mAb together with IL-4, but they showed impaired responsiveness to IL-5, regardless of enhanced expression of IL-5R in response to anti-CD40 mAb and IL-4. These results suggest that anti-CD40 mAb, IL-4 and IL-5 play a critical role in the differentiation of mouse GC B cells. The GC B cells from XID mice show a functional defect with respect to IL-5-mediated differentiation.

Initial stage of DNA-electrotransfer into E. coli cells

The mechanism of electrotransfer of DNA into Escherichia coli cells was investigated under conditions optimal for genetic transformation or transfection. Simple mixing in 10% polyethylene glycol 6000 did not cause binding of DNA to the recipient bacteria. When subjected to a high electric field, however, 90-98% of the input plasmid or phage DNAs were complexed with the cells. By application of the electric field, a significant amount of biotin-labeled DNA was bound onto the recipient surface, as detected by fluorescein isothiocyanate coupled avidin. When subjected to a high voltage pulse, DNA molecules were rapidly attracted toward the anode. Concurrently, the electric field induced the orientation of bacterial cells, along the field lines and their movement toward the anode. Since the bacterial movement was relatively slow, a substantial fraction of DNA molecules must strike the cathode-facing end or side of the recipient cells. Irrespective of the high efficiency of DNA transformation, the voltage pulse did not induce release of alkaline phosphate and beta-galactosidase. The electrotransferred DNA first remained sensitive to Tris-EDTA treatment, and became refractory to spheroplasting only after incubation at 37 degrees C. These results indicate that the infecting DNA is electrophoretically plugged to the outer membrane loosened by the voltage pulse.

The N-terminal sequence of Lactococcus lactis phosphoglucose isomerase purified by affinity chromatography differs from the other species

A specific monoclonal antibody, M3A, was produced to rapidly purify Lactococcus lactis phosphoglucose isomerase (PGI) for amino acid sequence analysis. M3A recognized the Lac. lactis PGI specifically and sensitively with both enzyme-linked immunosorbent assay and Western blot analysis. The enzyme was rapidly purified to a specific activity of 21.8 U/mg with a yield of 20% by a three-step procedure, including M3A-bound Sepharose chromatography. The specific activity of PGI was increased about 64.1-fold from the cell lysate. The molecular mass of Lac. lactis PGI was estimated to be about 50 kDa by SDS-PAGE. The N-terminal amino acid sequence of Lac. lactis PGI exhibited no significant similarity to other PGIs, except for a 52.6% identity to Bacillus stearothermophilus PGI A and PGI B. These results suggest that there might be some molecular types of PGI.

Accumulation of somatic hypermutation and antigen-driven selection in rapidly cycling surface Ig+ germinal center (GC) B cells which occupy GC at a high frequency during the primary anti-hapten response in mice

Well-developed germinal centers (GC) contain rapidly dividing surface immunoglobulin-negative (sIg-) B cells (centroblasts), and most of their progeny are sIg+ B cells (centrocytes) in a resting state. It has been predicted that somatic hypermutation occurs in centroblasts, whereas antigen-driven selection takes place in centrocytes. The present analysis indicates that murine GC B cells bearing sIg with specificity for an immunizing antigen are in a rapidly cycling state and increase exponentially in number to occupy spleen GC at high frequency during the 1st week after primary immunization; however, the number of these cells is significantly reduced in the 2nd week of immunization. During that period, these proliferating sIg+ GC B cells accumulate somatic hypermutations with nucleotide exchanges indicative of affinity maturation. These sIg+ GC B cells co-express B7-2, ICAM-1, and LFA-1, and have potent antigen-presenting activity which results in T cell activation in vitro. These observations indicate that the sIg+ GC B cells accumulate somatic hypermutations and undergo antigen-driven selection through proliferation, probably upon activation by T cells. This sIg+ GC B cell population may represent cell cycling centrocytes; however, the possibility that these may represent centroblasts undergoing re-expression of sIg could not be excluded.

CD43 expression in a B cell lymphoma, WEHI 231, reduces susceptibility to G1 arrest and extends survival in culture upon serum depletion

CD43 is a major surface sialoprotein on hemopoietic cells, whose extracellular domain is heavily O-glycosylated. The functional role of CD43 in the hemopoietic system is not fully understood; however, it has been suggested that CD43 may have a role in cell-cell repulsion and in modifying T cell proliferation and activation. CD43 is expressed in immature B cells in the bone marrow, but not by peripheral B cells, except for B-1 B cells and plasma cells. To analyze the biological effect of CD43 in B-lineage cells, we transfected mouse CD43 cDNA into a CD43- B cell lymphoma, WEHI 231, and the growth and survival in culture were compared to those of a parental cell line, human CD8 transfectants, and CD43- revertants established from CD43+ clones. We observed that CD43 expression supported cell growth in culture upon serum reduction, whereas growth of CD43- cell lines was barely detected under this condition. CD43- cell lines accumulated in G1 phase of the cell cycle, and the numbers of viable cells were greatly reduced during culture upon serum depletion, whereas expression of CD43 reduced the susceptibility to G1 arrest and temporarily retarded the apoptotic process, which, in turn, resulted in an increase and maintenance of the number of viable cells in culture. The results suggest that CD43 may have some role in the survival and expansion of B-lineage cells. The biological effect of CD43 was initiated without stimulation by cross-linking and was significantly impaired by replacement of the extracellular domain by the human CD8 extracellular domain. The basis of these regulatory processes is discussed.

A new and efficient method for gene transfer into mouse FM3A cells using metaphase chromosomes by electroporation

We introduced chromosome-mediated genes into mouse thymidine kinase-deficient FM3A (FM3Atk-) cells, by electroporation. The effects of some parameters on the electric shock-mediated transfection of FM3Atk- cells were investigated. Gene transfer of mouse L929 metaphase chromosome DNA into FM3Atk- resulted in a maximum frequency of (3.0 +/- 0.3) x 10(-5) at a cell density of 2.0 x 10(8)/ml and chromosome dosage of 5.0 x 10(7) cell equivalents/ml in a buffer containing 0.25 M mannitol, 0.5 mM MgCl2, 0.1mM CaCl2, and 1 mM Tris-HCl (pH 7.1). The highest yield of the transformants was obtained at an electric field strength of 1 kV/cm and a capacitance of 35 microF, with a single exponentially decaying pulse at 0 degrees C was optimal for post-shock incubation after electroporation. The tk gene was detected in the transformants by in situ hybridization analysis.

Expression of Vpre-B3 (8HS-20) molecules by alternative RNA processing

In pre-B cells, mu chains are expressed in association with "surrogate' L chains encoded by the lambda 5 and Vpre-B1 genes. In addition to their association with lambda 5 and Vpre-B1, mu chains in pre-B cells are associated with the products of the Vpre-B3 gene (formerly designated 8HS-20), which display a distinct association with mu chains and biochemical properties in terms of mol. wt, pI value and glycosylation. However, the mechanism of the generation of Vpre-B3 isoforms has been unknown. The present study indicates that the Vpre-B3 gene transcript underwent alternative RNA processing in normal B cells, in a pre-B cell lymphoma and in a mature B cell lymphoma, WEHI 231, that was transfected with the Vpre-B3 genomic clone. Vpre-B3 isoforms were expressed in a WEHI 231 cell line transfected with the Vpre-B3 genomic clone, comparable in biochemical nature to those expressed in a pre-B cell lymphoma. In contrast, expression of one of the isoforms was missing in a cell line transfected with the Vpre-B3 cDNA clone. These results suggest that Vpre-B3 isoforms with distinct biochemical characteristics are derived from alternatively processed Vpre-B3 mRNA.

Studies on electrotransfer of DNA into Escherichia coli: effect of molecular form of DNA

Effects of several molecular forms of DNA were examined on voltage-pulse-mediated transfection or transformation. Among circular DNAs, the single-stranded microvirid DNA was less infective than the double-stranded replicative form, whereas transfectivity of the relaxed or nicked molecule was nearly equal to or slightly lower than that of the supercoiled DNA. The linearized double-stranded DNA derived from phage or plasmid electrotransfects Escherichia coli, albeit at a reduced efficiency. Alkaline denaturation of the linearized DNA resulted in complete loss of the infectivity. Relationship between terminal structure of the linearized DNA and efficiency of the transfection was investigated. Host recombination function did not significantly affect the infectivity of the linearized DNA.

The virion proteins encoded by bacteriophage phi K and its host-range mutant phi KhT: host-range determination and DNA binding properties

The microvirid phage phi K, specific for Escherichia coli K12, contains a circular single-stranded (SS) DNA in the icosahedral virion, which comprises four phage gene products, F (capsid), G (major spike), H (minor spike), and J (core). phi KhT, a host-range mutant of phi K, can grow on E. coli C and B, besides K12, and is more thermosensitive than the parental phage phi K. Sequencing analysis revealed that the genome of phi K and phi KhT consists of 6,089 nucleotides (nt), and codes for eleven genes, whose sequences are similar to those of alpha 3, phi X174, and G4 infective to strain C. In phi KhT, two nt had changed: one is in the gene G, resulting in replacement of the 75th codon Ala with Ser, and the other is at 67th codon of the gene H: Val to Ala. Chemically synthesized gene J protein composed of 23 amino acids (aa) binds to phi K SS DNA more tightly than and preferentially over the host E. coli SS-DNA-binding protein (SSB). These results indicate that the two spike proteins G and H are involved in the determination of phi K host-range, and support a model in which the gene J protein functions in packaging the viral SS DNA into the virion vesicle.

Optical resolution of 1-arylethanols with a condensed aromatic ring by lipase from Pseudomonas aeruginosa

Enantioselective syntheses of both enantiomers of 1-arylethanols with a condensed aromatic ring have been done through acetylation of the racemic alcohols with vinyl acetate in the presence of a lipase from Pseudomonas aeruginosa (Toyobo, LIP). The lipase LIP showed high enantioselectivity and reactivity for the title compounds, reacted acetates, and remaining alcohols were obtained with high optical purity.

Cerebral hemodynamics on near-infrared spectroscopy in hypoxia and ischemia in young animal studies

Using near-infrared spectroscopy the changes of intracranial oxyhemoglobin, deoxyhemoglobin, total hemoglobin and cytochrome aa3, which show the progression of intracranial oxygenation, hemodynamics and cell metabolism, were recorded during prolonged partial hypoxia induced by carbon dioxide (CO2) and nitrogen (N2), ischemia induced by hyperventilation, and hypoxia during hypoglycemia in neonatal and young rabbits. The reduction of cytochrome aa3 during the terminal stage of CO2-induced prolonged hypoxia, hyperventilation and hypoxia in hypoglycemia suggests that the redox state of cytochrome aa3 will be changed by several combined factors such as oxygen delivery, ATP demand and substrate (glucose) delivery.

The effect of acetazolamide and carbon dioxide on cerebral hemodynamic changes on near-infrared spectroscopy in young rabbits

The changes of cerebral blood oxyhemoglobin (HbO2), deoxyhemoglobin (HbR), and total hemoglobin (tHb) induced by acetazolamide and CO2 loading on near-infrared spectroscopy (NIRS) were recorded. In anesthetized 2-week-old rabbits, acetazolamide (10 mg/kg i.v.) increased HbO2 and tHb, concomitant with an increase in tissue PCO2, and decreased HbR only at 5 and 10 min. CO2 loading significantly increased HbR and decreased HbO2, and after the termination of CO2 loading, tHb and HbO2 significantly increased and HbR decreased to nearly the baseline value. Thus, NIRS demonstrated cerebral hemodynamic responses as a function of vasomotor reactivity to acetazolamide as well as CO2 loading.

Monocyte-derived cultured dendritic cells are susceptible to human immunodeficiency virus infection and transmit virus to resting T cells in the process of nominal antigen presentation

The susceptibility of monocyte-derived cultured dendritic cells (DCs) to human immunodeficiency virus (HIV) infection and their role in viral transmission in the immune response were studied in detail. We observed that highly purified cultured DCs were infected with the T-tropic Lai strain of HIV type 1 (HIV-1Lai) via the CD4 receptor, and this was followed by formation of the complete provirus as detected by PCR. HIV mRNAs were transcribed at only low levels, and virus production was undectable; however, the addition of the purified protein derivative antigen of tuberculin and of autologous resting T cells to HIV-1Lai-infected DCs but not to HIV-1Lai-infected macrophages led to massive HIV transmission and production. These data suggest that the interaction of infected DCs with T cells during the normal immune response could play an important role in the activation and expansion of HIV.

Human cell clones, RSa and UVr-1, differing in their capability for UV-induced virus reactivation and phenotypic mutation

UVr-1 is a human cell clone established as a variant with increased resistance to cell killing by ultraviolet light (UV, principally 254 nm wavelength) from a UV-sensitive cell clone, RSa. Both cells have been characterized to have much the same capacity of UV-induced DNA repair synthesis in whole cells, and the parent RSa cells were recently found to be hypermutable. In the present study UVr-1 cells were characterized in comparison RSa cells with respect to UV-induced virus reactivation and phenotypic mutation. Survival levels of UV-irradiated vaccinia virus and herpes simplex virus type 1 (HSV-1) were much the same in logarithmically proliferating UVr-1 and RSa cells. Correlated with these host cell reactivation levels, the same extent of UV-induced DNA repair replication synthesis was observed in isolated nuclei of the two cell clones. Enhancement of survival levels of UV-irradiated HSV-1 was detected when proliferating RSa cells were irradiated with UV prior to the virus infection. In contrast, this enhanced virus reactivation (EVR) was not detected in similarly irradiated and infected UVr-1 cells. As for phenotypic mutation frequencies assessed by the cloning efficiency of cells with increased resistance to ouabain cell killing (OuaR), OuaR mutants were not obtained from UVr-1 cells either with or without UV irradiation. When the proliferation of cells was synchronized, both EVR and OuaR mutations were detected in RSa cells irradiated with UV at any cell cycle phase, being greatest in the later half of the G1 phase. However, there was no detectable EVR or mutation in any phase of synchronous UVr-1 cells. The hypomutability of UVr-1 cells and hypermutability of RSa cells in a G1 cell cycle phase was also found even if 4-nitroquinoline 1-oxide was used as a mutagen or mutant cells with increased resistance to 6-thioguanine cell killing were estimated.

The fetal thymus stores immature hemopoietic cells capable of differentiating into non-T lineage cells constituting the thymus stromal element

Immature hemopoietic cell lines were established by transforming fetal thymocytes in vitro with a ts mutant of Abelson murine leukemia virus. They are positive for c-kit and IL-2R alpha but negative for lineage specific markers. Their TCR and Ig heavy chain genes are in germline configuration, and are expressed as germline gene transcripts. When these cell lines were stimulated in vitro with IL-1 their morphology changed into that of typical macrophages (M phi). Subsequent analysis of a particular clone, which displayed the morphological change at the highest efficiency among established cell lines, indicated that the clone possesses the capacity to differentiate into I-A-M phi capable of secreting several cytokines, and supporting the proliferation of fetal and adult thymocytes in vitro. If their surface markers are considered, their normal counterparts would be present in a minor subset of CD4-CD8- double-negative cells in the thymus in early development. The results raise the possibility that the thymic organ at an early stage of development stores immature hemopoietic cells capable of differentiating into a non-T lineage constituting the thymic stromal elements.

Heavy chain variable (VH) region diversity generated by VH gene replacement in the progeny of a single precursor cell transformed with a temperature-sensitive mutant of Abelson murine leukemia virus

Sequence analysis of a large number of DNA clones containing a functional heavy chain variable, diversity, and joining (VHDJH) complex generated by VH to VHDJH joining (VH gene replacement) in the progeny derived from a common precursor cell transformed with a temperature-sensitive (ts) Abelson murine leukemia virus (A-MuLV) indicates that endogenous VH gene replacement in vitro generates immunoglobulin gene joints distinct from those generated by the usual VH to DJH joining. Such joints keep the pentamer CAAGA at the 3' end of the donor VH segment and lack a recognizable D segment, as can be seen also in vivo. The results suggest that VH gene replacement participates in generating VH region diversity in vivo, as previously postulated. During the joining process, a unique VH gene was selected in all progeny cells, together with a single A nucleotide dominantly added to the junctional boundaries. The basis of these regulatory processes is discussed.

Prediction of unbound serum valproic acid concentration by using in vivo binding parameters

In a previous study, we determined the in vivo binding parameters of valproic acid (VPA) to serum proteins in seven healthy young adults at steady state by using the Scatchard equation. To evaluate the ability of the Scatchard binding equation to predict steady-state unbound serum VPA concentrations (Cf), 39 adult patients receiving VPA monotherapy and ranging in age from 16 to 68 years were studied. The correlation between predicted and observed Cf was high (r = 0.865). Mean prediction error, mean absolute error (MAE), and root mean squared error (RMSE) were calculated, and served as a measure of prediction bias and precision. The MAE and RMSE were low (MAE = 12.9 mumol/L, RMSE = 17.7 mumol/L). It is feasible to use the Scatchard binding equation to predict Cf in patients receiving VPA monotherapy.

Binding parameters of valproic acid to serum protein in healthy adults at steady state

Two hundred milligrams of valproic acid (VPA) was administered orally to seven healthy adults at 9:00 and 21:00 h for 5 consecutive days, including the morning dose on day 6. On the sixth day, blood samples were drawn at 0, 0.17, 0.33, 0.5, 0.75, 1, 1.5, 3, and 6 h after the morning dose. Binding of VPA to serum protein was evaluated by ultrafiltration, and total and unbound VPA concentrations were determined by fluorescence polarization immunoassay. Binding parameters of VPA to serum protein were calculated for each subject by the Scatchard analysis. The binding parameters obtained from seven subjects showed that the mean association constant (K) was 2.72 x 10(4) L/mol while the total number of binding sites (nPt) was 789 mumol/L. There were marked interindividual variations and the coefficient of variation was 42% for K and 28% for nPt. These results show that endogenous free fatty acids (FFAs) significantly reduce the binding affinity of VPA to serum albumin (p less than 0.05). In addition, they suggest the possibility that the primary binding sites for VPA can be strongly reduced by FFAs. Therefore, we consider that interindividual differences in binding parameters may be clinically important.