The ability of biomarkers to assess the severity of atopic dermatitis

Background

To develop precision medicine for atopic dermatitis (AD), it is critical to establish relevant biomarkers. However, the characteristics of various biomarkers have not been fully understood. We previously carried out the Biomarkers to Predict Clinical Improvement of AD in Patients Treated with Dupilumab (B-PAD) study, a comprehensive nationwide study in Japan, to explore biomarkers for AD.

Objective

The aim of this study is to find biomarkers associated with objective and subjective clinical findings in patients with moderate-to-severe AD based on the B-PAD study and to identify biomarkers sensitive enough to assess the severity of AD.

Methods

We performed the B-PAD study as a consortium composed of 19 medical facilities in Japan, enrolling 110 patients with moderate-to-severe AD. We evaluated the Eczema Area and Severity Index (EASI) for objective assessment as well as the Patient-Oriented Eczema Measure (POEM) and a numeric rating scale for pruritus (pruritis-NRS) for subjective assessment, measuring 19 biomarkers at baseline.

Results

We found that 12, 6, and 7 biomarkers showed significant and positive associations with the EASI, POEM, and pruritis-NRS, respectively. Most of the biomarkers associated with either the POEM or the pruritis-NRS were included among the biomarkers associated with EASI. Of the biomarkers examined, CCL26/eotaxin-3 and SCCA2 were the most capable of assessing severity for EASI, as shown by the 2 kinds of receiver operating characteristic analyses, respectively, whereas lactate dehydrogenase was the best for both the POEM and pruritis-NRS, again using the 2 analyses.

Conclusion

We found biomarkers associated with the EASI, POEM, and pruritis-NRS, respectively, based on the B-PAD study. Moreover, we identified CCL26/eotaxin-3 and/or SCCA2 as the biomarkers having the greatest ability to assess severity in the EASI; lactate dehydrogenase did the same for the POEM and pruritis-NRS. These findings will be useful in treating patients with moderate-to-severe AD.

Age distribution and prevalence in different age groups of four myositis-specific autoantibodies, including anti-ARS, anti-MDA5, anti-Mi-2, and anti-TIF1γ antibodies

We accumulated the demographic information and analyzed the prevalence of myositis-specific antibodies (MSAs) in a large cohort across Japan as standard testing for MSAs becomes more widely available. This retrospective, observational, cohort study analyzed the records of individuals aged 0-99 years who are tested for serum MSAs at SRL Incorporation from January 2014 to April 2020 across Japan. An enzyme-linked immunosorbent assay testing was applied to determine the presence of anti-aminoacyl tRNA synthetase (anti-ARS), anti-Mi-2, anti-melanoma differentiation-associated gene 5 (anti-MDA5), or anti-transcriptional intermediary factor 1-γ (anti-TIF1γ) (Medical and Biological Laboratories). Anti-TIF1γ antibody was detected more in male patients than female patients. In contrast, women were predominant in patients with other MSAs. More than half of the anti-ARS or anti-TIF1γ antibody-positive patients were over 60 years old, although anti-MDA5 or anti-Mi-2-positive patients were mostly under <60 years old. Anti-MDA5 antibody-positive patients were mostly aged 40-59 years, while other MSA groups were mostly 60-79 years. Anti-MDA5 antibody was detected most frequently in the age range of 0-29 years. Anti-TIF1γ antibody was the second most commonly detected autoantibody in the age range of 0-19 years. Anti-ARS antibody was the most frequently detected autoantibody after the age of 30 years, and the frequency of anti-ARS gradually increased at more advanced ages. The second and third most detected autoantibodies were anti-MDA5 and anti-TIF1γ, respectively, in ages 30-79 years. We performed a nationwide >3-year evaluation of MSA detection in a routine diagnostic setting. This paper provides clinical images concerning the relationship between four MSA types and the distribution of sex and age in a large population.

Cell surface-expressed Ro52/IgG/HLA-DR complex is targeted by autoantibodies in patients with inflammatory myopathies

Intracellular proteins are often targeted by autoantibodies in autoimmune diseases; however, the mechanism through which intracellular molecules are targeted remains unknown. We previously found that several intracellular misfolded proteins are transported to the cell surface by HLA class II molecules and are recognized by autoantibodies in some autoimmune diseases, such as rheumatoid arthritis, antiphospholipid syndrome, and microscopic polyangiitis. Ro52 is an intracellular Fc receptor that is a target antigen for myositis-associated autoantibodies. We analyzed the role of HLA class II molecules in the autoantibody recognition of Ro52. Ro52 alone was not transported to the cell surface by HLA class II molecules; however, it was transported to the cell surface in the presence of both IgG heavy chain and HLA class II molecules to form a Ro52/IgG/HLA-DR complex. The Ro52/IgG/HLA-DR complex was specifically recognized by autoantibodies from some patients with inflammatory myopathies. We then evaluated 120 patients with inflammatory myopathies with four types of myositis-specific antibodies and analyzed the autoantibodies against the Ro52/IgG/HLA-DR complex. The specific antibodies against the Ro52/IgG/HLA-DR complex were detected in 90% and 93% of patients who were positive for anti-MDA5 and anti-ARS antibodies, respectively. In individual patients with these two inflammatory myopathies, changes in serum titers of anti-Ro52/IgG/HLA-DR-specific antibodies were correlated with the levels of KL-6 (R = 0.51 in anti-MDA5 antibody-positive DM patients, R = 0.67 in anti-ARS antibody-positive PM/DM patients with respiratory symptoms) and CK (R = 0.63 in anti-ARS antibody-positive PM/DM patients with muscle symptoms) over time. These results suggest that antibodies against Ro52/IgG/HLA-DR expressed on the cell surface could be involved in the pathogenesis of inflammatory myopathy subgroups.

Exploration of biomarkers to predict clinical improvement of atopic dermatitis in patients treated with dupilumab: A study protocol

BACKGROUND

Atopic dermatitis (AD) is a common eczematous skin disorder that profoundly reduces the quality of life due to intractable pruritus. Excellent therapeutic success of the anti-interleukin 4 receptor-α antibody dupilumab in clinical trials and a real-world clinical context indicates the crucial roles of interleukin (IL)-4 and IL-13 in the pathogenesis of AD. Along with the clinical improvement in skin scores and pruritus, dupilumab significantly and progressively reduces and normalizes the upregulated expression of T helper type 2 signatures such as Chemokine (C-C motif) ligand (CCL)17, CCL18, CCL22, and CCL26 in the lesional skin of AD. However, no blood/serum biomarkers are known to predict good or poor outcome in patients with AD treated with dupilumab.

METHODS

Patients are at least 18 years of age and have moderate-to-severe AD with Eczema Area and Severity Index (EASI) ≥16, Investigator's Global Assessment ≥3, and body surface area ≥10%. We are going to enroll more than 130 subjects from 18 medical facilities. Clinical objective findings will be evaluated by EASI. Subjective symptoms will be assessed by Patient-Oriented Eczema Measure, Numerical Rating Scale for Pruritus (Pruritus-NRS), Skin Comfort-NRS, and Treatment Satisfaction-NRS. We will measure 18 blood/serum biomarkers including % eosinophils in blood cell count, lactate dehydrogenase, total IgE, soluble interleukin 2 receptor, CCL17, CCL18, CCL22, CCL26, CCL27, IL-13, IL-22, IL-24, IL-25, IL-31, IL-33, thymic stromal lymphopoietin, periostin, and squamous cell carcinoma antigen-2. The clinical evaluation and biomarker sampling will be performed at 0, 2, 4, 8, and 16 weeks of dupilumab treatment. We will also perform proteomic analysis (of roughly 300 proteins) of the patients' sera obtained at 0 and 2 weeks of treatment. The primary endpoint is the association between "baseline levels of 18 biomarkers" and "% change from baseline of EASI at 16 weeks of dupilumab treatment."

DISCUSSION

This is the first clinical trial to explore the biomarkers, including potential proteomic markers, most strongly associated with improvement in EASI in patients with moderate-to-severe AD treated with dupilumab for 16 weeks (B-PAD study). A limitation is that we will only enroll Japanese patients.

Transcriptional intermediary factor 1 (TIF1) and anti-TIF1γ antibody-positive dermatomyositis

Recently, great advancements have been made towards understanding the mechanisms underlying dermatomyositis (DM). Many novel autoantibodies, such as anti-MDA5, anti-TIF1γ, anti-NXP2, and anti-SAE, have been reported to be involved in DM. DM is now classified based on these myositis-specific autoantibodies. Anti-TIF1γ antibodies are closely associated with juvenile DM and adult cancer-associated DM. Anti-TIF1γ antibody-positive DM tends to present severe cutaneous manifestations, mild myositis, and dysphagia. TIF1γ (also known as TRIM33) plays a role in transcriptional elongation, DNA repair, differentiation of cells, embryonic development, and mitosis. Moreover, TIF1γ has been shown to suppress various tumors via the TGF-β/Smad and the Wnt/β-Catenin signaling pathways. In this review, we explore the relationship between TIF1γ, cancer, and DM. We also discuss the pathogenesis of anti-TIF1γ antibody-positive DM.

Clinical characteristics and treatment of 50 cases of Blau syndrome in Japan confirmed by genetic analysis of the NOD2 mutation

Objectives

To collect clinical information and NOD2 mutation data on patients with Blau syndrome and to evaluate their prognosis.

Methods

Fifty patients with NOD2 mutations were analysed. The activity of each NOD2 mutant was evaluated in HEK293 cells by reporter assay. Clinical information was collected from medical records through the attending physicians.

Results

The study population comprised 26 males and 24 females aged 0–61 years. Thirty-two cases were sporadic, and 18 were familial from 9 unrelated families. Fifteen different mutations in NOD2 were identified, including 2 novel mutations (p.W490S and D512V); all showed spontaneous nuclear factor kappa B activation, and the most common mutation was p.R334W. Twenty-six patients had fever at relatively early timepoints in the disease course. Forty-three of 47 patients had a skin rash. The onset of disease in 9 patients was recognised after BCG vaccination. Forty-five of 49 patients had joint lesions. Thirty-eight of 50 patients had ocular symptoms, 7 of which resulted in blindness. After the diagnosis of Blau syndrome, 26 patients were treated with biologics; all were antitumour necrosis factor agents. Only 3 patients were treated with biologics alone; the others received a biologic in combination with methotrexate and/or prednisolone. None of the patients who became blind received biologic treatment.

Conclusions

In patients with Blau syndrome, severe joint contractures and blindness may occur if diagnosis and appropriate treatment are delayed. Early treatment with a biologic agent may improve the prognosis.

[A CASE OF FOOD-DEPENDENT EXERCISE-INDUCED ANAPHYLAXIS BY SHRIMP: FRUCTOSE 1, 6- BISPHOSPHATE ALDOLASE IS SUPPOSED AS CAUSATIVE COMPONENT DESPITE NEGATIVE ALLERGEN-SPECIFIC IGE TEST (IMMUNOCAP®)]

A 16-year-old male high-school student experienced generalized itchy wheal and dyspnea during physical exercise after lunch. Each food material of his lunch was examined using a prick-prick test, allergen-specific IgE test (ImmunoCAP^®), and provocation test. The prick-prick test was positive for black tiger shrimp (raw and heated) and white leg shrimp (heated). Allergen-specific IgE test (ImmunoCAP^®) showed absolutely negativity for all suspected foods. The food-exercise provocation test using heated black tiger shrimp with additional aspirin intake finally induced anaphylaxis.We studied the IgE-binding molecules from shrimp using a purification procedure and Western blotting, with sera from the patient and several controls. A 40-kDa protein, corresponding to FBA, was found to be the major IgE-binding allergen component in this patient. Currently, the precise history and the prick-prick test using both raw and heated shrimps are useful to diagnose shrimp-induced FDEIA. Because the allergen-specific IgE test is insufficient to diagnose the cause of the symptoms, a component allergen-specific IgE test after the identification of the causative allergenic protein, such as FBA, is required.

Effect of chlorine substitution on the biodegradability of polychlorinated biphenyls

Thirty-one isomers of polychlorinated biphenyl (PCB) were examined for biodegradability by two species of Alcaligenes and Acinetobacter. The following relationships between chlorine substitution and biodegradability of PCBs were observed. (i) Degradation decreased as chlorine substitution increased. PCB isomers containing more than four chlorines were less susceptible to degradation. (ii) PCBs containing two chlorines on either the ortho position of a single ring (i.e., 2,6-) or on both rings (i.e., 2,2'-) showed very poor degradability. (iii) PCBs containing all chlorine atoms on only a single ring were generally degraded faster than when the same number of chlorines were substituted on both rings. (iv) Preferential ring fission of the molecules occurred with nonchlorinated or lesser chlorinated rings. (v) The formation and accumulation of a yellow intermediate was always observed in 4'-chloro-substituted PCBs. (vi) Significant differences between the two organisms with respect to degradability were not observed except for 2,4,6-trichlorobiphenyl.

Genetic Rearrangement of Plasmids: In Vivo Recombination between a Dehalogenation Plasmid and Multiple-Resistance Plasmid RP4 in Pseudomonas sp

When Moraxella plasmid pUO1 encoding haloacetate dehalogenase and mercury resistance coexisted with IncP-1 plasmid RP4 in Pseudomonas sp., genetic exchange between the plasmids often occurred, probably by site-specific recombination. The recombinant plasmids obtained were classified into four groups on the basis of phenotype. Representative plasmids for each group were analyzed for DNA composition and function, and the mechanism for the formation of these plasmids was sought. They were inherited stably in Escherichia coli and a Pseudomonas sp.

Sequence analysis of 18S-28S rRNA spacer regions from Saccharomyces kunashirensis, S. martiniae, S. rosinii, and S. transvaalensis

Sequences of two internal transcribed spacer regions between 18S and 28S rRNA for recently described yeasts species, Saccharomyces kunashirensis, S. martiniae, S. rosinii, and S. transvaalensis, were determined to assess their phylogenetic relationship to the other Saccharomyces species. In the two phylogenetic trees constructed by the neighbor-joining method, independent branches reflected that delimitation of the four new species was valid.

Expression of the extracellular levansucrase and invertase genes from Zymomonas mobilis in Escherichia coli cells

We investigated the expression and localization in Escherichia coli of sucZE2 and sucZE3, encoding Zymomonas mobilis extracellular levansucrase and invertase, respectively, and lacking a typical N-terminal secretion signal. Levansucrase and invertase were expressed efficiently under the lac and tac promoters in E. coli cells, and some of the levansucrase produced was localized in the periplasmic space. The sucZE2 expression was not lethal to E. coli in the presence of 5% sucrose, and led to the accumulation of levan from sucrose.

Reexamination of yeast strains classified as Torulaspora delbrueckii (Lindner)

Twenty-eight yeast strains presumed to represent Torulaspora delbrueckii were analyzed by randomly amplified polymorphic DNA-PCR analysis. Four strains (HUT 7161, IFO 1138, IFO 1145, and IFO 1956) that were considerably different from the type strain were further investigated. Morphological and physiological characteristics revealed that strains HUT 7161 and IFO 1145 belong to the genus Debaryomyces rather than the genus Torulaspora, and the former strain may represent Debaryomyces hansenii. Strains IFO 1138 and IFO 1956 were classified as either Saccharomyces castellii or Saccharomyces dairensis by identification keys involving physiological tests. On the basis of analysis of the sequences of two rRNA internal spacer regions, strains IFO 1138 and IFO 1956 were closely related to S. castellii and strains HUT 7161 and IFO 1145 were outside members of the genera Torulaspora, Zygosaccharomyces, and Saccharomyces.

A phylogenetic analysis of Saccharomyces species by the sequence of 18S-28S rRNA spacer regions

Sequences of two internally transcribed spacer regions between 18S and 28S rRNA genes were determined to assess the phylogenetic relationship in the strains belonging to the genus Saccharomyces. The sequences of S. bayanus and S. pastorianus were quite similar, but not identical. Two phylogenetic trees constructed by the neighbor-joining method showed that all the species examined were distinguished from one another. The Saccharomyces sensu stricto species: S. cerevisiae, S. bayanus, S. paradoxus and S. pastorianus, were closely related and far from the Saccharomyces sensu lato species including S. barnetti, S. castellii, S. dairensis, S. exiguus, S. servazzii, S. spencerorum and S. unisporus, and an outlying species, S. kluyveri.

Polycaprolactone depolymerase produced by the bacterium Alcaligenes faecalis

Several microorganisms were isolated as bacteria degrading polycaprolactone (PCL), and one of them, a strain B273 identified as Alcaligenes faecalis, was selected. Because this strain produced only slight PCL depolymerase activity, the hyperproducing mutant, TS22, was isolated after UV irradiation. Synthesis of PCL depolymerase was derepressed, probably based on the altered regulation of metabolic pathways in strain TS22. The partially purified enzyme hydrolyzed p-nitrophenyl fatty acids and triglycerides other than PCL, but not poly(3-hydroxybutyrate), indicating that PCL depolymerase may be a kind of lipase.

Purification and properties of poly(3-hydroxybutyrate) depolymerase from the fungus Paecilomyces lilacinus D218

Poly(3-hydroxybutyrate) depolymerase was purified to homogeneity from the culture filtrate of Paecilomyces lilacinus D218 by column chromatography on CM-Toyopearl 650M and hydroxylapatite. The molecular weight of the enzyme was estimated to be 48,000 by SDS-PAGE. Maximal activity was observed near pH 7.0 and 45 degrees C. The Km and Vmax values for PHB were 0.13(mg/ml) and 3750 (U/mg protein), respectively. The enzyme hydrolyzed PHB and p-nitrophenyl fatty acids but not polycaprolactone and triglycerides.

Detection of maltose fermentation genes in the baking yeast strains of Saccharomyces cerevisiae

The presence of any one of the five unlinked MAL loci (MAL1, MAL2, MAL3, MAL4 and MAL6) confers the ability to ferment maltose on the yeast Saccharomyces cerevisiae. Each locus is composed of three genes encoding maltose permease, alpha-glucosidase and MAL activator. Chromosomal DNA of seven representative baking strains has been separated by pulse-field gel electrophoresis and probed with three genes in MAL6 locus. The DNA bands to which all of the three MAL-derived probes simultaneously hybridized were chromosome VII carrying MAL1 in all of the strains tested, chromosome XI carrying MAL4 in six strains, chromosome III carrying MAL2 in three strains and chromosomes II and VIII carrying MAL3 and MAL6, respectively, in the one strain. The number of MAL loci in baking strains was comparable to those of brewing strains.

Electrophoretic karyotyping of the yeast genus Torulaspora

Karyotypes of yeast strains in the genus Torulaspora were determined by pulse-field gel electrophoresis and compared with those of the related genus Zygosaccharomyces. The DNA bands ranged from 800 to 1600 kb in T. delbrueckii and 800 to 2000 kb in both T. globosa and T. pretoriensis and those numbers were about six in the three species. The chromosomes of Torulaspora strains comprised relatively smaller size of DNAs than Zygosaccharomyces strains.

Use of haloacetate dehalogenase genes as selection markers for Escherichia coli and Pseudomonas vectors

The haloacetate dehalogenase gene, dehH2, cloned from Moraxella sp. strain B could be used a selection marker gene for vectors in Escherichia coli and Pseudomonas putida. Haloacetates, especially iodoacetate, inhibit the growth of some microorganisms. The dehH2 gene introduced into the cells conferred iodoacetate resistance on them. Therefore, E. coli and P. putida transformed with vectors marked with dehH2 could be easily selected on plates containing iodoacetate.

Cloning and characterization of Zymomonas mobilis genes encoding extracellular levansucrase and invertase

The genes encoding the extracellular levansucrase and invertase of Zymomonas mobilis have been cloned and sequenced. The levansucrase gene, sucZE2, spans 1269 bp and encodes an M(r) 46,790 polypeptide, and the invertase gene, sucZE3, is of 1239 bp and encodes an M(r) 46,110 polypeptide. The 5'-terminal sequences of both genes corresponded to the N-terminal amino acid sequences of the secreted levansucrase and invertase, implying that the secretion of both enzymes does not involve proteolytic processing of the N-terminals. Both enzyme molecules appear to carry no typical N-terminal secretion signal. Significant homology between sucZE2 and sucZE3 was observed, but both genes showed no homology to the gene encoding an intracellular invertase coexisting in Z. mobilis. Two genes, sucZE2 and sucZE3, are possibly placed in an operon because the expression of two genes were simultaneously controlled by the regulator gene zliE, previously identified.

Molecular genetic properties of the yeast Torulaspora pretoriensis: characterization of chromosomal DNA and genetic transformation by Saccharomyces cerevisiae-based plasmids

Chromosomal DNA banding patterns were obtained for three strains of Torulaspora pretoriensis by contour-clamped homogeneous-electric-field gel electrophoresis. Chromosomes were resolved into six or seven bands in the range of 800 to 2000 kb, and a polymorphism of these lengths was observed. By Southern-blot analysis, the three strains were shown to lack the DNA sequences homologous to the URA3, LEU2, TRP1, and HO genes of Saccharomyces cerevisiae. A uracil auxotrophic mutant derived from T. pretoriensis was transformed with three plasmids (YEp24, YRpHI, and YCp50) carrying the URA3 gene of S. cerevisiae by the lithium acetate method.

Cloning and characterization of a pair of genes that stimulate the production and secretion of Zymomonas mobilis extracellular levansucrase and invertase

A 1.7-kb DNA fragment cloned from Zymomonas mobilis genomic DNA complemented the inability to grow on sucrose of a Suc- mutant of Z. mobilis that was deficient in the production of both extracellular levansucrase and invertase. Analysis of the nucleotide sequence of the fragment found two open reading frames (ORFs), both of which did not correspond to the structural gene for the levansucrase or the invertase. By subcloning each ORF into two different Suc- mutants of Z. mobilis, it has been found that the first ORF (gene zliE) activates the production of the extracellular levansucrase and invertase, and the second ORF (gene zliS) stimulates the secretion of the two enzymes. Gene zliS might contribute to the secretion of proteins having no signal peptide. The expression of zliE and zliS seemed to be under the control of the same promoter.

Cloning and sequence analysis of a plasmid-encoded 2-haloacid dehalogenase gene from Pseudomonas putida No. 109

The 2-haloacid dehalogenase of Pseudomonas putida No. 109 was mediated by a 74-kb conjugative plasmid, which was transferred by mating into Pseudomonas and Escherichia coli and there expressed the dehalogenase. A 2.8-kb EcoRI-fragment generated from the plasmid was cloned and sequenced. The dehalogenase gene (dehH109) was identified by comparison with the N-terminal amino acid sequence and the molecular weight of the enzyme protein. The gene dehH109 coded for a 224-amino acid protein of M(r) 25,231, which showed significant homology to the other four L-specific 2-haloacid dehalogenases from Pseudomonas sp. CBS3, P. putida AJ1, and Xanthobacter autotrophicus GJ10 and also to the haloacetate dehalogenase H-2 from Moraxella sp. strain B, but no homology with another haloacetate dehalogenase H-1 and the D-specific 2-haloacid dehalogenase from P. putida AJ1.

Purification and characterization of alpha-glucosidase from Torulaspora pretoriensis YK-1

alpha-Glucosidase was partially purified 103-fold from a cell-free extract of Torulaspora pretoriensis YK-1 by column chromatography on Toyopearl HW55F, DEAE-Toyopearl 650M, hydroxylapatite and phenyl-Toyopearl 650M. Further purification by preparative polyacrylamide gel electrophoresis (PAGE) gave the homogenous protein, but the specific activity was reduced. The molecular weight of the enzyme was estimated to be 69,000 by SDS-PAGE and 60,000 by gel filtration. Optimum pH and temperature were 6.8 and 35 degrees C, respectively. The enzyme was inhibited strongly by AgNO3, HgCl2, sodium dodecyl sulfate, and N-ethylmaleimide. The Km (mM) for p-nitrophenyl alpha-D-glucopyranoside, maltose, maltotriose, isomaltose, methyl alpha-glucoside, and sucrose were 0.15, 150, 45, 17, 18, and 29, and Vmax (mumol/min/mg protein) for those substrates were 87, 0.23, 2.4, 9.0, 12, and 7.4, respectively. The N-terminal amino acid sequence of the enzyme was PEVKNHPETQPKWWKEATVY. The properties of alpha-glucosidase from T. pretoriensis YK-1 were similar to those from Saccharomyces cerevisiae.

Lack of homology between two haloacetate dehalogenase genes encoded on a plasmid from Moraxella sp. strain B

Two genes encoding haloacetate dehalogenases, H-1 and H-2, are closely linked on a plasmid from Moraxella sp. strain B. H-1 predominantly acts on fluoroacetate, but H-2 does not. To elucidate the molecular relationship between the two enzymes, we compared their structural genes. Two restriction fragments of the plasmid DNA were subcloned on M13 phages and their nucleotide sequences were determined. The sequence of each fragment contained an open reading frame that was identified as the structural gene for each of the two dehalogenases on the basis of the following criteria; N-terminal amino acid sequence, amino acid composition, and molecular mass. The genes for H-1 and H-2, designated dehH1 and dehH2, respectively, had different sizes (885 bp and 675 bp) and G+C contents (58.3% and 53.4%). Sequence analysis revealed no homology between the two genes. We concluded that the dehalogenases H-1 and H-2 have no enzyme-evolutionary relationship. The deduced amino acid sequence of the dehH1 gene showed significant similarity to those of three hydrolases of Pseudomonas putida and a haloalkane dehalogenase of Xanthobacter autotrophicus. The dehH2 coding region was sandwiched between two repeated sequences about 1.8 kb long, which might play a part in the frequent spontaneous deletion of dehH2 from the plasmid.

Cloning, sequencing, and characterization of the intracellular invertase gene from Zymomonas mobilis

The structural gene for the intracellular invertase E1 of Zymomonas mobilis strain Z6C was cloned in a 2.25-kb DNA fragment on pUSH11, and expressed in Escherichia coli HB101. The enzyme produced by the E. coli carrying pUSH11 was purified about 1,122 fold to homogenicity with a yield of 4%. The molecular weight and substrate specificity of the enzyme were identical with those of the intracellular invertase E1 from Z. mobilis. The nucleotides of the cloned DNA were sequenced; they included an open reading frame of 1,536 bp, coding for a protein with a molecular weight of 58,728. The N-terminal amino acid sequence predicted was identical with the sequence of the first 20 N-terminal amino acid residues of the protein obtained by Edman degradation. Comparison of the predicted amino acid sequence of E1 protein with those of the four other known beta-D-fructofuranosidases from Escherichia coli, Bacillus subtilis, and Saccharomyces cerevisiae indicated a stronger homology in the N-terminal portion than in the C-terminal portion.

Implantable enzyme capsules for cancer chemotherapy from bakers' yeast cytosine deaminase immobilized on epoxy-acrylic resin and urethane prepolymer

For trial use in the local chemotherapy of cancer by a combination of cytosine deaminase (EC 3.5.4.1) and 5-fluorocytosine (J. Biotechnol., (1985), 2, 13-21), 40 U of partially purified cytosine deaminase was obtained from 500 g of commercial compressed bakers' yeast. The enzyme, which is unstable, was immobilized to stabilize it by the use of commercial epoxy-acrylic beads (Eupergit C). The immobilized enzyme was made into enzyme capsules with cellulose tubing for dialysis to encapsulate it or urethane polymer to entrap it, which materials are biocompatible. The activity of the intact cellulose capsules thus made was 0.4% that of the immobilized enzyme inside. The enzyme capsules also were stable. Ten days after the cellulose capsules were implanted in rats, 25% of the starting activity remained. When the polyurethane capsules were tested in vitro for 9 mo for thermostability at 37 degrees C, the activity decreased rapidly (with a half-life of 28 d) during the first 4 mo, and then slowly (half-life, about 100 d) during the next 5 mo. A calculation to transform the biphasic decline into a sum of the exponential decline of two components of enzymic activities with different strengths and half-lives showed that the larger half-life was 5 mo.