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Biomedical subjects

S Ishino

Publications and source records attributed to S Ishino.

At least 19 recordsLinked to original sources
PubMed1996

Construction of catalase deficient Escherichia coli strains for the production of uricase.

To produce catalase-free uricase preparations, we constructed catalase-deficient strains from Escherichai coli MC1000 and MM294 and used them as recombinant host strains. The parent strains and catalase-deficient strains showed no differences in the growth characteristics by shaking culture in Erlenmeyer flasks. The catalase deficient strain derived from MC1000 transformed with the uricase expression plasmid pUT118 (strain SN0037) had growth characteristics and the uricase productivity comparable to those of the parent host strain MC1000 in fed-batch culture in a jar fermentor and no catalase activity was detected in cell-free extracts. However, the katG disrupted strains from MM294 carrying pUT118 had poor growth and their uricase productivities were low compared to those of the parent strain MM294. Using the strain SN0037, a catalase-free uricase preparation was obtained with fewer purification procedures and the final recovery of uricase activity was improved. The catalase-deficient E. coli host strain will be a suitable host for the production of the uricase, free of catalase activity, in high yield.

Acatalasia↗
PubMed1995

Cloning, purification, and properties of a cofactor-independent glutamate racemase from Lactobacillus brevis ATCC 8287.

A glutamate racemase gene of Lactobacillus brevis ATCC 8287 was cloned into Escherichia coli TM93 by the phenotypic complementation of a phosphoenolpyruvate carboxylase deficiency on minimum agar medium containing D-glutamate. The gene was localized to a 1.4-kb HindIII-EcoRI DNA fragment and the total nucleotide sequence of the fragment was analyzed. The gene has typical promoter and SD sequences which appeared to function in E. coli. The deduced amino acid sequence of the enzyme had 276 amino acids and the molecular weight was calculated as 29,426. Two cysteine residues and their surrounding regions of the enzyme are homologous to those of other cofactor-independent racemases. The glutamate racemase was purified from recombinant E. coli to homogeneity and characterized. The enzyme required no cofactors for the activity, and retained its activity even in 2 M (300 g/l) L-glutamate.

Amino Acid Isomerases↗
PubMed1995

[Alexia-agraphia of kanji (Japanese morphogram) after left posterior-inferior temporal lesion].

Several cases of selective alexia with agraphia of kanji have been reported in Japan in this decade. It is well known that the lesion in the posterior inferior temporal lobe of the dominant hemisphere is responsible for this cognitive syndrome. Neuropsychological data in our patient suggest that the postero-inferior region of the temporal lobe of the dominant hemisphere may be the visuo-verbal association area for the analysis of the complex visuo-verbal information. The symptoms caused by the same lesion in western patients might be subangular alexia (alexia without agraphia). Alexia with agraphia of kanji and subangular alexia would appear to be distinct entities, but a dual processing hypothesis of visuo-verbal information and the concept of the visuo-verbal association area might well explain both syndromes.

Agraphia↗
PubMed1994

Effects of the amplification of the genes coding for the L-threonine biosynthetic enzymes on the L-threonine production from methanol by a gram-negative obligate methylotroph, Methylobacillus glycogenes.

We constructed recombinant plasmids carrying the genes coding for the L-threonine biosynthetic enzymes, the hom gene, the hom-thrC genes, and the thrB genes, of a gram-negative obligate methylotroph, Methylobacillus glycogenes, and examined the effects of them on the production of L-threonine from methanol. The hom gene, which encodes the homoserine dehydrogenase, and the hom-thrC genes, containing the gene coding for threonine synthase together with the hom gene, were cloned from a wild-type strain, and the thrB gene encoding the desensitized homoserine kinase was cloned from an L-threonine-producing mutant, ATR80. The recombinant plasmids were transferred into ATR80 and its L-isoleucine auxotroph, A513, by conjugation. Amplification of the genes coding for the L-threonine biosynthetic enzymes elevated the activities of the L-threonine biosynthetic enzymes of the transconjugants 10- to 30-fold over those of the strains containing only vectors. The L-threonine production from methanol in test-tube cultivation was increased about 30% and 40% by the amplification of the hom gene and the hom-thrC gene respectively, and it was slightly increased by that of the thrB gene. The effects of gene amplification were confirmed by the cultivation in 5-1 jar fermentors. The best producer, an A513 transconjugant containing the plasmid carrying the hom-thrC genes, produced 16.3 g/l L-threonine for 72 h.

Biotechnology↗
PubMed1994

Cloning and nucleotide sequences of the homoserine dehydrogenase genes (hom) and the threonine synthase genes (thrC) of the gram-negative obligate methylotroph Methylobacillus glycogenes.

We have cloned the homoserine dehydrogenase genes (hom) from the gram-negative obligate methylotrophs Methylobacillus glycogenes ATCC 21276 and ATCC 21371 by complementation of an Escherichia coli homoserine dehydrogenase-deficient mutant. The 4.15-kb DNA fragment cloned from M. glycogenes ATCC 21371 also complemented an E. coli threonine synthase-deficient mutant, suggesting the DNA fragment contained the thrC gene in addition to the hom gene. The homoserine dehydrogenases expressed in the E. coli recombinants were hardly inhibited by L-threonine, L-phenylalanine, or L-methionine. However, they became sensitive to the amino acids after storage at 4 degrees C for 4 days as in M. glycogenes. The structures of the homoserine dehydrogenases overexpressed in E. coli were thought to be different from those in M. glycogenes, probably in subunit numbers of the enzyme, and were thought to have converted to the correct structures during the storage. The nucleotide sequences of the hom and thrC genes were determined. The hom genes of M. glycogenes ATCC 21276 and ATCC 21371 encode peptides with M(r)s of 48,225 and 44,815, respectively. The thrC genes were located 50 bp downstream of the hom genes. The thrC gene of ATCC 21371 encodes a peptide with an M(r) of 52,111, and the gene product of ATCC 21276 was truncated. Northern (RNA) blot analysis suggests that the hom and thrC genes are organized in an operon. Significant homology between the predicted amino acid sequences of the hom and thrC genes and those from other microorganisms was found.

Amino Acid Sequence↗
PubMed1993

Lymphoplasmacytic lymphoma in a stallion.

Lymphoplasmacytic lymphoma found in a 6-year-old Anglo-Arabian stallion was investigated histologically, immunohistochemically and ultrastructurally. The animal showed a large mediastinal mass and generalized lymph node involvement. The neoplastic cells were in various differentiation stages of small lymphocyte, centrocyte, centroblast, immunoblast and plasma cell. Some neoplastic cells showed positive cytoplasmic reactivity for mu and lambda chains. There were well developed rough endoplasmic reticulum (RER) and Golgi complexes in plasmacytoid cells, and slightly developed RER or a few long strands of RER in medium-sized to large lymphoid cells. These findings suggest that this neoplasm is of B-cell origin.

Animals↗
PubMed1992

A case of bovine sex cord tumour with annular tubules.

A case of sex cord tumour with annular tubules was found in the right ovary of a 17-month-old Holstein cow. The tumour was characterized by tubules encircling hyaline bodies, which were composed of concentric lamellae of basal lamina. Several irregular tubular structures and a small component of granulosa cell differentiation were seen. Immunohistochemically, the neoplastic cells stained positively for oestradiol or testosterone.

Animals↗
PubMed1992

Immunohistochemical observations on pneumonic lesions caused by Rhodococcus equi in foals.

An immunohistochemical analysis of Rhodococcus equi-induced pneumonia in 10 foals was performed by biotin-streptavidin system. The detection of R. equi was more sensitive in immuno-stain using anti-R. equi serum than in Gram's stain. This bacteria also reacted to anti-BCG serum. Lysozyme and alpha 1-antitrypsin were detectable in macrophages. A particularly intense staining was observed in association with intracellular bacteria. Though a degree of reaction for alpha 1-antichymotrypsin was very low in comparison with lysozyme and alpha 1-antitrypsin, it was also demonstrated in macrophages ingesting R. equi. These bacteria were almost intact under an electron microscope. Therefore, the surface components of R. equi may play important roles of protection from intracellular enzymes of macrophages. The cells containing intracytoplasmic IgM, IgG or IgA were a few in number and scattered predominantly around the pneumonic lesion. It is considered that the bactericidal activity by immunoglobulins may be weak in comparison with phagocytosis by macrophages.

Actinomycetales Infections↗
PubMed1991

Immunohistochemical studies on ontogeny of bovine lymphoid tissues.

Developing lymphoid tissues of bovine fetuses ranging from 70 to 270 days of fetal age were examined by histological and immunohistochemical procedures. In the peripheral blood, surface membrane immunoglobulin bearing cells (B-lymphocytes) and sheep red blood cell rosette forming cells (T-lymphocytes) had already appeared by 70 days of fetal age. In the lymph nodes intracytoplasmic IgM positive cells appeared at 90 days of fetal age. The cells positive for IgG appeared at 150 days of fetal age and IgA positive cells appeared at 180 days of fetal age. The spleen contained intracytoplasmic immunoglobulin positive cells at almost the same time as those in the lymph nodes. In the ileocecal region, IgM positive cells and IgG positive cells were present at 180 days of fetal age and IgA positive cells were present at 210 days of fetal age. The tonsils contained IgM positive cells and IgG positive cells at 240 days of fetal age. In the thymus, terminal deoxynucleotidyl transferase positive cells appeared at 90 days of fetal age.

Animals↗
PubMed1990

Pathological and immunohistochemical studies of follicular lymphoma in two calves.

Pathological and immunohistochemical studies were performed on two cases of bovine follicular lymphoma with severe leukaemia and antibodies to bovine leukaemia virus. Histologically, numerous neoplastic follicular structures were observed in the lymph nodes and spleen of both cases and in the tonsils and Peyer's patches of one case. The neoplastic cells infiltrated diffusely into the liver, lungs and heart in both cases and into the tonsils, kidneys, abomasum and bone marrow in one case. Intracytoplasmic immunoglobulin was negative in the neoplastic cells. Follicular dendritic reticulum cells were decreased in number in the neoplastic follicles compared with those in normal lymphoid follicles. Follicular lymphoma is rare in cattle. Histological features of the present cases are distinguishable from the adult form of bovine lymphoma and the calf form of lymphoma.

Animals↗
PubMed1990

The mtr locus is a two-gene operon required for transcription attenuation in the trp operon of Bacillus subtilis.

We have cloned and characterized the mtr operon of Bacillus subtilis. This operon encodes a presumed RNA-binding regulatory protein that is required for attenuation control of the trp operon. We have shown that the mtr operon consists of two structural genes, mtrA and mtrB, predicted to encode 22-kDa and 8-kDa polypeptides, respectively. MtrB shows homology with RegA, an RNA-binding regulatory protein of bacteriophage T4. The lesions in several mtr mutants were localized to mtrB or the putative mtr promoter. Several mtrB alleles were dominant to mtr+, suggesting that the regulatory factor is a multimeric protein. The in vivo action of the mtrA and mtrB gene products was analyzed in an E. coli strain containing a trpE-lacZ gene fusion under control of the B. subtilis trp promoter/attenuator region. Both MtrA and MtrB were necessary for regulation of beta-galactosidase production.

Amino Acid Sequence↗
PubMed1990

Malignant lymphomas of thymus origin in two sows.

Two cases of swine thymic lymphoma were investigated by electron microscopy and the immunoperoxidase method for terminal deoxynucleotidyl transferase (TdT), and furthermore sheep erythrocyte rosette assay was applied to one case. In case 1, immunoblastoid cells predominated and smaller cells were admixed with them. Many neoplastic cells were TdT-positive and formed rosettes with sheep erythrocytes at 4 degrees C, but about half of them formed rosettes at 37 degrees C. Ultrastructurally the neoplastic cells were characterized by highly irregular nuclei, poorly developed organelles and clustered dense bodies. The neoplasm in case 2 was composed of medium-sized to large cells and the latter predominated. A few of the neoplastic cells stained positively with anti-TdT serum. Ultrastructurally the neoplastic cells were characterized by nuclear convolution, narrow cytoplasmic bands and clustered dense bodies. The morphological features of thymic lymphomas were discussed in comparison with those of other swine lymphomas and lymphomas of other animals. Histological and immunological progression into T-immunoblastoid cells in case 1 was also discussed.

Animals↗
PubMed1989

Malignant lymphomas of follicular centre cell origin in 14 pigs.

Malignant lymphomas of follicular centre cell (FCC) origin in 14 pigs are described. Seven cases were classified as abdominal type according to the distribution of the neoplastic lesions and the residual cases were of the general type. Most cases were composed of mixed populations of large and medium-sized neoplastic cells and the growing pattern varied from partially follicular to diffuse. The neoplastic cells often showed necrosis, to which macrophages reacted. A part of the neoplastic cells had cytoplasmic immunoglobulin M (CIgM) or cytoplasmic immunoglobulin G (CIgG). The histological features of swine FCC lymphomas are discussed.

Abdominal Neoplasms↗
PubMed1989

Immunoperoxidase evaluation of pneumonic lesions in calves naturally infected with Pasteurella haemolytica.

Immunoperoxidase technique was applied for pathological study on naturally occurring pneumonic tissues of calves from which Pasteurella haemolytica was isolated. Multifocal necrosis occurred in the lungs of 25 out of 42 calves (59.5%) and P. haemolytica antigen was detected in 22 out of the 25 calves (88.0%). The calves were divided into 3 groups according to the number of P. haemolytica isolated. The positive rate of the bacterial antigen detected by the technique was 66.6% (28/42) on the average, reaching up to 85.7% (18/21) in the group from which the largest number of P. haemolytica was isolated.

Animals↗
PubMed1989

Development and serial passage of persistent lymphocytosis associated with bovine leukemia virus infection in cattle.

Two calves each were inoculated with 1.5 x 10(8) or 5 x 10(9) lymphocytes collected from each one cow which had persistent lymphocytosis (PL) and antibodies to bovine leukemia virus (BLV). A sudden increase in the number of peripheral blood lymphocytes (PBL) was observed 14 and 23 days, respectively, after inoculation and the maximum number reached 29,000 and 52,000/microliters 72 and 57 days after inoculation. Although the degree of PL decreased gradually in these cattle, it continued until 14 and 44 months after inoculation when one animal was sacrificed and the other died of lymphosarcoma. The PL was passaged in cattle by inoculation of a large number of PBL obtained from cattle at the stage of PL (PLL). The degree of PL was severer in cattle inoculated with a larger number of PLL. PL was not caused by inoculation of PBL obtained from either BLV-infected non-PL cattle or cattle free of BLV. The PL was also caused by inoculation of PLL into BLV-infected non-PL cattle. On the other hand, it was not observed after inoculation of a large amount of cell-free virus obtained from short-term cultures of PLL. Antibodies to BLV developed earlier and to higher levels in cattle inoculated with PLL than in those inoculated with cell-free virus. These facts show that infection with BLV was established more effectively by PLL than by cell-free virus, the infection may occur by lymphocyte to lymphocyte interaction and the actual number of infected BLV may have an important role in development of PL.

Animals↗
PubMed1989

Characteristics of lymphocytes appearing in persistent lymphocytosis induced experimentally in cattle by bovine leukemia virus infection.

Properties of peripheral blood lymphocytes (PBL) appearing during persistent lymphocytosis (PL) of cattle that was induced by inoculation of a large number of bovine leukemia virus (BLV)-infected lymphocytes were studied. The PBL possessed surface immunoglobulin at a high ratio and had high syncytium-forming activity. The PBL could not be distinguished from normal PBL cytogenetically. These PBL were shown to be polyclonal cells integrating BLV-proviral DNA randomly into their cellular DNA. These properties were similar to those of PBL appearing at the stage of PL of cattle naturally infected with BLV. The BLV-proviral DNA content of PBL and transcription of viral genes increased in parallel with development of PL and decreased along with a decline of PL indicating the possibility that gene expression and activation of BLV play an important role in induction and maintenance of PL.

Animals↗
PubMed1989

Pathological findings of two types of lymphoid malignancy in sheep inoculated with bovine leukemia virus.

Different types of lymphoid malignancy were observed in two sheep inoculated with BLV-containing materials. Sheep 1 showed severe leukemic change in the peripheral blood and splenomegaly but lymphosarcoma in the lymph nodes was absent. Sheep 2 had lymphosarcoma in the lymph nodes and various organs. Neoplastic cells had B-cell marker in both cases and a few neoplastic cells contained intracytoplasmic IgM in sheep 2. It was presumed that B-cells might be transformed into neoplastic cells on the way of their differentiation. Some of neoplastic cells might have ability of immunoglobulin-production in sheep 2.

Animals↗