Marine Microorganism: An Underexplored Source of l-Asparaginase.

l-Asparaginase (EC 3.5.1.1) is an enzyme that catalyzes the hydrolysis of l-asparagine to l-aspartic acid. This enzyme has an important role in medicine and food. l-Asparaginase is a potential drug in cancer therapy. Furthermore, it is also applied for reducing acrylamide, a carcinogenic compound in baked and fried foods. Until now, approved l-asparaginases for both applications are few due to their lack of appropriate properties. As a result, researchers have been enthusiastically seeking new sources of enzyme with better performance. A great number of terrestrial l-asparaginase-producing microorganisms have been reported but unfortunately, almost all failed to meet criteria for cancer therapy and acrylamide reducing agent. As a largest area than Earth, marine environment, by contrast, has not been optimally explored yet. So far, a great challenge facing an exploration of marine microorganisms is mainly due to their harsh, mysterious, and dangerous environment. It is clear that marine environment, a gigantic potential source for marine natural products is scantily revealed, although several approaches and technologies have been developed. This chapter presents the historical of l-asparaginase discovery and applications. It is also discussed, how the marine environment, even though offering a great potency but is still one of the less explored area for l-asparaginase-producing microorganisms.

E1A, E1B double-restricted replicative adenovirus at low dose greatly augments tumor-specific suicide gene therapy for gallbladder cancer.

Combination therapy with replicative oncolytic viruses is a recent topic in innovative cancer therapy, but few studies have examined the efficacy of oncolytic adenovirus plus replication-deficient adenovirus carrying a suicide gene. We aim to evaluate whether an E1A, E1B double-restricted oncolytic adenovirus, AxdAdB-3, can improve the efficacy for gallbladder cancers (GBCs) of the replication-deficient adenovirus-based herpes simplex virus thymidine kinase (HSVtk)/ganciclovir (GCV) therapy directed by the carcinoembryonic antigen (CEA) promoter. Cytopathic effects of AxdAdB-3 plus AxCEAprTK (an adenovirus expressing HSVtk directed by CEA promoter) or AxCAHSVtk (an adenovirus expressing HSVtk directed by a nonspecific CAG promoter) with GCV administration were examined in several GBC lines and normal cells. Efficacy in vivo was tested in severe combined immunodeficiency disease mice with GBC xenografts. Addition of AxdAdB-3 (1 multiplicity of infection, MOI) significantly enhanced the cytopathic effects of AxCEAprTK (10 MOI)/GCV on GBC cells. The augmented effect was attributable to the replication of the AxCEAprTK and also to the enhanced CEA promoter activity, which was presumably transactivated by E1A. In normal cells, AxdAdB-3 (20 MOI) plus AxCEAprTK (200 MOI)/GCV was not cytopathic, whereas AxdAdB-3 (1 MOI) plus AxCAHSVtk (10 MOI)/GCV was significantly toxic. Low-dose AxdAdB-3 (2 x 10(7) PFU, plaque-forming unit) plus AxCEAprTK (2 x 10(8) PFU)/GCV significantly suppressed the growth of GBC xenografts as compared with either AxdAdB-3 (2 x 10(7) PFU)/GCV or AxCEAprTK (2 x 10(9) PFU)/GCV alone. E1A, E1B double-restricted replicating adenovirus at low dose significantly augmented the efficacy of CEA promoter-directed HSVtk/GCV therapy without obvious toxicity to normal cells, suggesting a potential use of this combination for treating GBC and other CEA-producing malignancies.

Histopathological features of murine systemic vasculitis caused by Candida albicans extract--an animal model of Kawasaki disease.

OBJECTIVE AND DESIGN: We examined the histopathological features of systemic vasculitis caused in mice by injection of a Candida albicans ( C. albicans) extract and investigated the principal genetic roles in the development of vasculitis. MATERIALS AND METHODS: C. albicans extract was injected intraperitoneally for five consecutive days in the 1st and 5th weeks to CD-1, C57BL/6N, C3H/HeN, BALB/cAnN, DBA/2N and CBA/JN mice. At week 8, mice were killed, and histological examination was performed by light microscopy. RESULTS: Arteritis had developed in 66% of CD-1 mice. The extramural coronary arteries and aortic root close to the orifice of coronary arteries were most frequently involved. Histologically, the characteristic feature of the arteritis was proliferative and granulomatous inflammation accompanied by numerous macrophages, lymphocytes, plasma cells and neutrophils. Fibrocellular intimal thickening with destruction of the internal elastic lamina and media was also observed. Five mouse strains after injection of C. albicans extract were clearly classified into a resistant group (CBA/JN, DBA/2N and BALB/cAnN mice) and a sensitive group (C3H/HeN and C57BL/6N mice). The inbred mouse strains which showed the same histocompatibility-2 (H-2) haplotype exhibited a different susceptibility to development of vasculitis. CONCLUSION: This arteritis murine model shows unique histological features that have not been observed in other animal vasculitis models and it most closely resembles Kawasaki disease in humans. The genetic control of susceptibility to induction of vasculitis by the C. albicans extract is dependent to the mouse strains, but is not linked to the H-2 loci.

Deep-seated mycosis as a complication in bone marrow transplantation patients.

Achieving control of opportunistic fungal infections which occur during the course of immunosuppressive therapy is one of the key factors deciding the success or failure of bone marrow transplantation (BMT). A review was conducted of autopsied patients who had undergone BMT at the University of California at Los Angeles Medical Center in the USA between 1985 and 1994. The incidence of complication by deep-seated mycoses was determined, and the causative fungal species and invaded organs were elucidated. Deep fungal infections were found to have occurred in 31.5% (47/149 cases) of the BMT patients, and disseminated disease was found in approximately one-quarter of the infected cases. The findings suggest that BMT patients, who require the use of potent immunosuppressive agents, show increased susceptibility to the development of more serious, and widespread diffuse fungal infections. The most commonly detected causative fungi were Aspergillus species and Candida species. In addition, it was found that the incidence of candidosis had decreased markedly in recent years; conversely, aspergillosis had increased. It was surmised that these findings reflect the development of antifungal agents which are effective against candidosis and have enabled a reduction in the incidence of this disease even in BMT patients, whereas aspergillosis remains difficult to treat. In consideration of these findings regarding the manifestation of deep-seated mycosis in BMT patients, we conclude that in order to increase the success rate of BMT it will be essential to establish safe and effective methods for the prevention and treatment of aspergillosis.

Histopathology of cryptococcosis and other fungal infections in patients with acquired immunodeficiency syndrome.

OBJECTIVE: To gain insight into the histopathologic characteristics of fungal infection in acquired immunodeficiency syndrome (AIDS). METHODS: A review was conducted of the histopathology for 162 patients with evident fungal infection. RESULTS: The microscopic appearance of esophageal candidiasis that was common in patients with single organ involvement revealed necrotic debris containing proliferating hyphae at the site of mucosal erosions without fungal invasion of underlying tissue. The incidence of oral and esophageal candidiasis was followed by that of pulmonary aspergillosis and Candida infection. Eighteen patients had generalized cryptococcosis, representing the commonest generalized fungal disease. The essential histologic features of the disease consisted of yeast cell proliferation with a histiocytic response, but only minor lymphocytic and neutrophilic components. This was different from the manifestations of both Candida and Aspergillus infections. The two histologic patterns recognized in the pulmonary cryptococcal lesions could be graded with respect to the degree and type of inflammatory reaction. The milder one consisted of small scattered foci of intra-alveolar cryptococcal proliferation with a histiocytic response. Another pattern involved massive cryptococcal infection, which might be simply more extensive than that in the former. Capillary involvement of alveolar septa was an important common finding in all 18 patients.

Penile schwannoma.

Schwannoma of the penis is extremely rare. A 65-year-old man presented with a subcutaneous tumor of penile shaft without any other symptoms. Histopathologic examination of the excised tumor revealed benign schwannoma. No recurrence has been observed over the 6 months since the surgery.

Extracellular matrix components in a case of retrocorneal membrane associated with syphilitic interstitial keratitis.

PURPOSE: A web-like retrocorneal membrane (RCM) is an uncommon complication of chronic syphilitic interstitial keratitis. Extracellular matrix components have not yet been defined in this structure, although previous histologic examinations have suggested the presence of collagen. We examined the presence and distribution of extracellular matrix components in a patient with an RCM. METHODS: A specimen of the opaque cornea affected by syphilitic interstitial keratitis with RCM formation was obtained during penetrating keratoplasty in a 62-year-old woman and was evaluated by histology, immunohistochemistry, and scanning electron microscopy (SEM). Antibodies against collagen types I, III, and IV; fibronectin; vimentin; alpha-smooth muscle actin (alpha-SMA); heat shock protein 47 (Hsp 47); proliferating cell nuclear antigen (PCNA); and Ki67 were used. RESULTS: Histologic analysis detected multiple concentric, acellular layers positive for collagen types I, III, and IV. The corneal endothelial cells (CECs) were positive for vimentin, collagen I, fibronectin, and Hsp 47 but not for alpha-SMA. Furthermore, the CECs were negative for PCNA and Ki67, indicating that they were not proliferating. SEM revealed the RCM was covered by CECs with a fibroblastic appearance. CONCLUSION: RCM associated with syphilitic interstitial keratitis contained collagen types I, III, and IV and fibroblast-like CECs. These CECs may secrete the extracellular matrix components found in the RCM. Hsp 47 up-regulation in the CECs may play an important role in RCM formation. These findings provide further insights into the phenotypic modulation of CECs.

Oscillator representations and systems of ordinary differential equations.

Using representation-theoretic methods, we determine the spectrum of the 2 x 2 system. Q(x, D(x)) = A- partial differential(2)(x)2 + x(2)2 + Bx partial differential(x) + 1/2, x in, with A, B in Mat(2)(R) constant matrices such that A = (t)A > 0 (or <0), B = -(t)B not equal 0, and the Hermitian matrix A + iB positive (or negative) definite. We also give results that generalize (in a possible direction) the main construction.

[Deep-seated mycosis in patients with solid-organ transplantation--a study of autopsied cases in the United States].

Autopsies with solid-organ trans plantation (SOT) in UCLA Medical Center were reviewed, especially focussing on the deep-seated fungal infection and the incidence of fungal infections, causative fungi, and organs involved were evaluated. Deep-stated fungal infections were demonstrated in 21.0% of the patients with SOT. The incidence of fungal infections were 26.1% in kidney transplantation, which was the highest rate in SOT autopsies we reviewed, 25.0% in liver transplantation, 14.3% in lung transplantation, and 13.2% in heart transplantation. And the most common causative fungi were Aspergillus species, seen in 70.6% of SOT autopsies. In contrast, Candida species were observed in 25.5%. In addition, the incidence of deep-seated mycosis has been increasing since 1992, this was parallel to the increase of aspergillosis, most of which were found as a generalized spreading. In contrast, candidal lesions, were almost limited to the digestive tracts. The above suggests that from this standpoint, improvement of prophylactic and therapeutic technique against aspergillosis is the greatest problem in deep-seated mycosis in SOT patients.

Role of conserved histidine residues in D-aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6.

D-Aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 (Alcaligenes A-6) was strongly inactivated by diethylpyrocarbonate (DEPC). An H67N mutant was barely active, with a kcat/Km 6.3 x 10(4) times lower than that of the recombinant wild-type enzyme, while the H67I mutant lost detectable activity. The H67N mutant had almost constant Km, but greatly decreased kcat. These results suggested that His67 is essential to the catalytic event. Both H69N and H69I mutants were overproduced in the insoluble fraction. The kcat/Km of H250N mutant was reduced by a factor of 2.5 x 10(4)-fold as compared with the wild-type enzyme. No significant difference between H251N mutant and wild-type enzymes in the Km and kcat was found. The Zn content of H250N mutant was nearly half of that of wild-type enzyme. These results suggest that the His250 residue might be essential to catalysis via Zn binding.

Purification and characterization of nitrite-oxidizing enzyme from heterotrophic Bacillus badius 1-73, with special concern to catalase.

Nitrite-oxidizing enzyme I (NiOx I) was purified from a heterotrophic bacterium, Bacillus badius I-73. The enzyme was a homotetramer of a heme-containing peptide, and was similar to catalases from various sources in its N-terminal amino acid sequence. The purified enzyme also catalyzed H2O2 degradation. The nitrite oxidation reaction required ascorbic acid and oxygen. Successive H2O2 feeding could be substituted for ascorbic acid. These indicated that NiOx I is a catalase and nitrite was oxidized by a peroxidase-like reaction.

Apolipoprotein A-I gene expression is upregulated by polychlorinated biphenyls in rat liver.

Xenobiotics such as polychlorinated biphenyls (PCB) increase serum cholesterol level (especially high density lipoprotein cholesterol) and apolipoprotein A-I (apo A-I) level in rats. The effect of PCB on serum apo A-I and hepatic apo A-I gene expression and the relationship between apo A-I and drug-metabolizing enzymes in rats were investigated. Serum levels of cholesterol and apo A-I were increased by dietary addition of PCB in a dose-dependent manner (0-500 mg/kg diet). Hepatic apo A-I mRNA level was also elevated by PCB in a similar fashion. Serum level of cholesterol gradually increased during feeding period of PCB (200 mg/kg diet, 105 days) and reached a two-fold higher level in PCB group than in controls. The levels of serum apo A-I and hepatic apo A-I mRNA linearly elevated during feeding period of PCB and were increased 3- or 4-fold, respectively, compared to controls. Although acute administration (16 hr) of PCB, 3-methylcholanthrene, and phenobarbital induced cytochrome P-450 gene expression in the liver, hepatic apo A-I gene expression was not increased by these xenobiotics. These results indicated that the serum levels of cholesterol and apo A-I had positive correlation with hepatic level of apo A-I mRNA in rats fed PCB, and that hepatic apo A-I gene expression was dependent upon intake of PCB but was not directly related to the induction of drug-metabolizing enzymes. This study demonstrated that xenobiotic-induced hyper-alpha-cholesterolemia would be caused by the increased apo A-I gene expression and cholesterol synthesis in the liver, coordinately.

Histopathology of experimental invasive pulmonary aspergillosis in rats: pathological comparison of pulmonary lesions induced by specific virulent factor deficient mutants.

To investigate the pathology of invasive pulmonary aspergillosis (IPA) in detail, a new animal model of IPA was used to compare the histological features induced by three different strains of Aspergillus fumigatus; mutants devoided of exocellular protease and rodlet and their parental strain. To produce an experimental pulmonary lesion of IPA closely mimicking the human disease, suspension of agarose beads containing conidiae of A. fumigatus were used as an inocula to fix infallibly the causative agents in alveoli and rats were treated with a low-dose of immunosuppressive drugs to avoid an induction of agranulocytosis in rodents. There was no significant difference in the mortality of mice with an intravenous injection between these three strains. However, IPA model in the study was successful to demonstrate a significant difference in the histological feature of lungs of infected rats. Pulmonary lesions on the fifth day after infection induced by the rodletless mutant were limited and inflammatory responses were weak when compared to those induced by both no exocellular protease mutant as well as their parental strain. The evidence of rodlet layer in conidia of Aspergilli may play an important role in the physiopathology of the disease in eliminating the neutrophils and macrophages of hosts on the early stage of the infection.

Overexpression of salt-tolerant glutaminase from Micrococcus luteus K-3 in Escherichia coli and its purification.

A high-expression plasmid, pKSGHE3-1, containing the salt-tolerant glutaminase (EC 3.5.1.2) from marine bacterium Micrococcus luteus K-3 was constructed. pKSGHE3-1 was made by inserting the DNA fragment (1.43 kb) containing the structural gene synthesized by polymerase chain reaction into the downstream region of the tac promoter of expression vector pKK223-3. The translational start codon was located 10 bases downstream of the Shine-Dalgarno sequence (AGGA) of pKK223-3. Escherichia coli JM109 transformed with pKSGHE3-1 exhibited more than 190-fold higher glutaminase activity than M. luteus K-3 under optimal culture conditions. The enzyme was purified to homogeneity through three column chromatography steps with a final yield of 17.1%. The recombinant enzyme showed the same enzymatic properties, including salt tolerance, as those of M. luteus K-3. This glutaminase expression system allows the production of sufficient quantities of glutaminase for basic structure-function studies including chemical modification and future X-ray crystallization analysis.

Purification and characterization of three thermostable endochitinases of a noble Bacillus strain, MH-1, isolated from chitin-containing compost.

A thermophilic and actinic bacterium strain, MH-1, which produced three different endochitinases in its culture fluid was isolated from chitin-containing compost. The microorganism did not grow in any of the usual media for actinomyces but only in colloidal chitin supplemented with yeast extract and (2, 6-O-dimethyl)-beta-cyclodextrin. Compost extract enhanced its growth. In spite of the formation of branched mycelia, other properties of the strain, such as the formation of endospores, the presence of meso-diaminopimelic acid in the cell wall, the percent G+C of DNA (55%), and the partial 16S ribosomal DNA sequence, indicated that strain MH-1 should belong to the genus Bacillus. Three isoforms of endochitinase (L, M, and S) were purified to homogeneity and characterized from Bacillus sp. strain MH-1. They had different molecular masses (71, 62, and 53 kDa), pIs (5.3, 4.8, and 4.7), and N-terminal amino acid sequences. Chitinases L, M, and S showed relatively high temperature optima (75, 65, and 75 degreesC) and stabilities and showed pH optima in an acidic range (pH 6.5, 5.5, and 5.5, respectively). When reacted with acetylchitohexaose [(GlcNAc)6], chitinases L and S produced (GlcNAc)2 at the highest rate while chitinase M produced (GlcNAc)3 at the highest rate. None of the three chitinases hydrolyzed (GlcNAc)2. Chitinase L produced (GlcNAc)2 and (GlcNAc)3 in most abundance from 66 and 11% partially acetylated chitosan. The p-nitrophenol (pNP)-releasing activity of chitinase L was highest toward pNP-(GlcNAc)2, and those of chitinases M and S were highest toward pNP-(GlcNAc)3. All three enzymes were inert to pNP-GlcNAc. AgCl, HgCl2, and (GlcNAc)2 inhibited the activities of all three enzymes, while MnCl2 and CaCl2 slightly activated all of the enzymes.

L-ornithine decarboxylase from Hafnia alvei has a novel L-ornithine oxidase activity.

A novel activity producing gamma-aminobutyric acid (GABA) from L-ornithine in the presence of NAD(P)+ was found in the crude extract of L-ornithine-induced Hafnia alvei, in addition to L-ornithine decarboxylase (ODC) activity. The reaction system for the former activity consisted of two enzymes, L-ornithine oxidase (decarboxylating, OOD) and gamma-aminobutyraldehyde (GABL) dehydrogenase (GDH). OOD catalyzed the conversion of L-ornithine into GABL, CO2, NH3, and H2O2 in the presence of O2, and GDH dehydrogenated GABL to GABA in the presence of NAD(P)+. OOD, purified to homogeneity, had a high ODC activity and the activity ratio of ODC to OOD was almost constant throughout the purification (ODC/ OOD=160:1). The molecular mass of the OOD was about 230 kDa, probably consisting of three identical subunits of a 77 kDa peptide, and OOD had an absorption maximum at 420 nm as well as at 278 nm, the specific absorption for an enzyme containing pyridoxal phosphate (PLP). The content of PLP was estimated at about 1 mol per subunit. OOD was specific to L-ornithine, and other L-amino acids and polyamines including putrescine were inert. The enzyme was activated by PLP, but not by pyridoxamine 5'-phosphate, FAD, FMN, or pyrroloquinoline quinone, and it was inactivated by hydrazine, semicarbazide, and hydroxylamine. The holoenzyme can be resolved to the apoenzyme by incubation with hydroxylamine, and reconstituted with PLP. These properties of OOD were almost the same as those of ODC separately purified to homogeneity from H. alvei. Zn2+ and Cu2+, butanedione, and sodium borohydride inhibited both OOD and ODC in a similar manner. The OOD reaction required O2 and only the ODC reaction proceeded under anaerobic conditions. The substitution of air for oxygen in the reaction vessel and the addition of catalase-H2O, enhanced only the OOD reaction, resulting in an increase of the ratio of OOD/ODC to 1:30 and 1:4.1, respectively. These results suggested that OOD and ODC are identical and that the former is a side reaction of the latter in the presence of O2.

[A patient with Sjögren syndrome with central pontine myelinolysis and hypokalemic myopathy].

We report a 42-year-old woman who presented with intermittent episodes of muscular weakness lasting approximate 7 to 10 days, about once a year, since 1985. During these episodes of weakness, hypokalemia and elevation of serum creatine kinase were noted. On admission, xerostomia, keratoconjunctivitis sicca (positive Schirmer test), abnormal sialographic findings (apple tree-like appearance), and positive serum autoantibodies against ss-A and nucleus were noted. These findings were compatible with Sjögren syndrome. She also had hyperchloremic metabolic acidosis with normal anion gap, hypokalemia and renal calcifications. Therefore, she had renal tubular acidosis (type 1) in addition to Sjögren syndrome. Brain magnetic resonance imaging (MRI) demonstrated a symmetrical circumscribed lesion in the ventral part of the central pons. We considered this lesion to be central pontine myelinolysis (CPM), because of its typical location and characteristic MRI appearance. This CPM was clinically silent. Pathogenesis and etiology of CPM are obscure, and CPM associated with hypokalemia without hyponatremia has rarely been reported in the literature. However, this is the first report of CPM associated with Sjögren syndrome and hypokalemic myopathy complicated with renal tubular acidosis.

Overproduction of D-aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6 in Escherichia coli and its purification.

We constructed the high-expression plasmid for D-aminoacylase from Alcaligenes xylosoxydans subsp. xylosoxydans A-6. The appropriate Shine-Dalgarno sequence (AAGGAG) was introduced to the eight bases upstream of start codon (ATG) of D-aminoacylase structural gene by site-directed mutagenesis, and then the 1.75-kb DNA fragment including the open reading frame was inserted into the downstream of the tac promoter of plasmid vector pKK223-3. The resultant plasmid, which was named pKNSD2, showed a high D-aminoacylase activity in Escherichia coli JM109 cells transformed with it. The enzyme was purified to homogeneity in only two steps with a final yield of 24% (sp act, 2023 U/mg).

Chemical modification of histidine residue of N-acyl-D-Glutamate amidohydrolase from Pseudomonas sp. 5f-1.

N-Acyl-D-glutamate amidohydrolase (D-AGase) from Pseudomonas sp. 5f-1 was inactivated by diethyl pyrocarbonate (DEP). The chemical modification by DEP showed a difference spectrum at 246 nm due to the N-carbethoxyhistidine residue. Removal of the carbethoxy group from inactivated enzyme with hydroxylamine restored enzyme activity. The inactivation by DEp proceeded with pseudo-first-order kinetics, and was protected in the presence of the substrate N-acetyl-D-glutamate (Glu), or the competitive inhibitor sodium alpha-ketoglutarate (alpha-KGA). These results suggest the presence of an essential histidine residue at or near of the active site of the enzyme.