Efficient induction of proximity-dependent labelling by biotin feeding in BMAL1-BioID knock-in mice

Proximity-dependent biotin identification (BioID) is a useful method to identify unknown protein-protein interactions. Few reports have described genetically engineered knock-in mouse models for in vivo BioID. Thus, little is known about the proper method for biotin administration and which tissues are applicable. Here, we established a BioID knock-in mouse model of Brain and Muscle ARNT-Like 1 (BMAL1) and the BirA biotin ligase with R118G mutation (BirA*). The BMAL1-BioID mouse model was used to investigate the effect of biotin diet feeding on protein biotinylation in several tissues. The BMAL1-BirA* fusion protein-retained proper intracellular localization of BMAL1 and binding to CLOCK protein in HEK293T cells. A biotin labelling assay in mouse embryonic fibroblasts revealed the protein biotinylation activity of BMAL1-BirA* expressed in knock-in mouse cells depending on biotin supplementation. Lastly, feeding a 0.5% biotin diet for 7 days induced protein biotinylation in the brain, heart, testis and liver of BMAL1-BioID mice without adverse effects on spermatogenesis. In the kidney, the biotin diet increased biotinylated protein levels in BMAL1-BioID and control mice, suggesting the existence of endogenous biotinylation activity. These results provide valuable information to optimize the in vivo BioID procedure.

Rapid cytologic diagnosis of choroidal malignant melanoma by vitreous smear

The eye is an uncommon subject of cytopathological examination. However, cytopathologic examination may be required for definitive diagnosis in some cases, as malignant tumors of the eye may sometimes be difficult to distinguish clinically from benign disorders. We report a case of malignant melanoma (MM) of the choroid, in which vitrectomy was performed for the initial clinical diagnosis of vitreous hemorrhage. As the dense vitreous hemorrhage was gradually cleared during the vitrectomy, a choroidal mass was discovered and the vitreous fluid was procured for rapid cytologic diagnosis. We used a modified Shorr's stain that can be completed within several minutes. With this method, highly atypical, pleomorphic cancer cells, occasionally associated with melanin pigment granules, were demonstrated. These cytologic findings indicated a diagnosis of MM arising from the choroid. Histologic examination of the enucleated eye confirmed MM of epithelioid type. The advantage and indication of the rapid cytologic diagnosis is discussed.

Characterization of the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase gene from Bacillus cereus YUF-4

A 1.4-kbp DNA fragment, including the NADH-linked acetylacetoin reductase/2,3-butanediol dehydrogenase (AACRII/BDH) gene from the chromosomal DNA of Bacillus cereus YUF-4, was cloned in Escherichia coli DH5alpha after its insertion into pUC119, and the resulting plasmid was named pAACRII119. The AACRII/BDH gene had an open reading frame consisting of 1047 bp encoding 349 amino acids. The enzyme exhibited not only AACR activity, but also BDH activity. However, the gene was not located in a 2,3-butanediol (BD) operon, as is the case in the BDH gene of Klebsiella pneumoniae and that of K. terrigena. In addition, there was no BD-cycle-related enzyme gene in the region surrounding the AACRII/BDH gene. The AACR and BDH activities in E. coli DH5alpha/pAACRII119 were 200-fold higher than those in the original B. cereus YUF-4. The characteristics of the AACRII/BDH from E. coli DH 5alpha/pAACRII119 are similar to those of the AACRII/BDH from B. cereus YUF-4. The AACRII/BDH was considered to belong to the NAD(P)- and zinc-dependent long-chain alcohol dehydrogenase (group I ADH) family on the basis of the following distinctive characteristics: it possessed 14 strictly conserved residues of microbial group I ADH and consisted of about 350 amino acids. The enzymatic and genetic characteristics of AACRII/BDH were completely different from those of BDHs belonging to the short-chain dehydrogenase/reductase family. These findings indicated that the AACRII/BDH could be considered a new type of BDH.

Production of large multienzyme complex by aerobic thermophilic fungus Chaetomium sp. nov. MS-017 grown on palm oil mill fibre

AIMS

A novel xylanolytic multienzyme complex of the aerobic thermophilic fungus Chaetomium sp. nov. MS-017 was produced on palm oil mill fibre (POMF) and partially characterized.

METHODS AND RESULTS

The assay of the extracellular enzymes of Chaetomium sp. nov. MS-017 on POMF in solid-state fermentation revealed cellulolytic, pectinolytic and extremely high xylanolytic activities. The protein was purified by Sephadex G-200 column chromatography. The SDS-PAGE demonstrated that the purified protein is a complex with at least five xylanolytic, four cellulolytic and eight pectinolytic components. The characterization of the complex at various temperatures showed that the reactivity and stability of the complex are not lost up to 60 degrees C. In addition, the complex was very stable in a wide range of pH (3-9) and at high concentrations (10 mm) of cations and EDTA. The major products of xylan hydrolysis by the purified complex were determined to be xylobiose and xylotriose by thin-layer chromatography.

CONCLUSION

Chaetomium sp. nov. MS-017 preferentially produces a xylanolytic multienzyme complex on POMF in solid-state fermentation.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report on the xylanolytic multienzyme complex produced by an aerobic thermophilic fungus.

Production of l-2,3-butanediol by a new pathway constructed in Escherichia coli

AIMS

A metabolic pathway for L-2,3-butanediol (BD) as the main product has not yet been found. To rectify this situation, we attempted to produce L-BD from diacetyl (DA) by producing simultaneous expression of diacetyl reductase (DAR) and L-2,3-butanediol dehydrogenase (BDH) using transgenic bacteria, Escherichia coli JM109/pBUD-comb.

METHODS AND RESULTS

The meso-BDH of Klebsiella pneumoniae was used for its DAR activity to convert DA to L-acetoin (AC) and the L-BDH of Brevibacterium saccharolyticum was used to reduce L-AC to L-BD. The respective gene coding each enzyme was connected in tandem to the MCS of pFLAG-CTC (pBUD-comb). The divided addition of DA as a source, addition of 2% glucose, and the combination of static and shaking culture was effective for the production.

CONCLUSIONS

L-BD (2200 mg l(-1)) was generated from 3000 mg l(-1) added of DA, which corresponded to a 73% conversion rate. Meso-BD as a by-product was mixed by 2% at most.

SIGNIFICANCE AND IMPACT OF THE STUDY

An enzyme system for converting DA to L-BD was constructed with a view to using DA-producing bacteria in the future.

Isolation of a novel thermophilic fungus Chaetomium sp. nov. MS-017 and description of its palm-oil mill fiber-decomposing properties

Palm-oil mill fiber (POMF) is a fibrous, natural hard material discharged in enormous amounts from palm-oil mills in tropical plantations; therefore, research to find microorganisms that decompose POMF was conducted. As the result of screening, a new thermophilic fungus, Chaetomium sp. nov. MS-017, exhibiting rapid growth on POMF was isolated from rotted wood. Based on partial characterization of the decomposition of POMF, it was shown that MS-017 preferentially assimilates polysaccharides, especially hemicelluloses such as xylan. A preliminary composting study indicated that MS-017 produced 855 g of decomposed product from 1,000 g of intact POMF in 12 days under optimized solid-culture conditions. The decomposition rate of POMF was 23% (w/w), and the cell yield calculated from consumed POMF was as high as 36% (w/w). These results indicate that MS-017 has a very high potential to decompose POMF and that it is suitable for economical production of compost to recycle by-product biomass from oil-palm plantations.

Senescence and cytoskeleton: overproduction of vimentin induces senescent-like morphology in human fibroblasts

One characteristic feature of senescent fibroblasts is flat, enlarged, and heterogeneous cell shapes. The present study was aimed to understand the structural basis of the senescent cell morphology. SDS-gel electrophoresis as well as western blotting demonstrated that there occurred a prominent protein band about 57 kDa in the senescent cells as compared with normal young or immortalized cells growing rapidly, and the protein was identified with a cytoskeletal protein, vimentin. In fact, senescent fibroblasts contained approximately threefold more vimentin protein, and fourfold more vimentin mRNA than young embryonic fibroblasts. In the senescent cells, vimentin cytoskeleton occurred as densely bundled filaments in parallel with the long axis of cell bodies, whereas in young or actively growing cells it showed short and thin vimentin filaments or fur-like irregular networks. It was further demonstrated that senescent cell shapes could be induced when a vimentin expression construct was transfected in young fibroblasts. These results suggest that senescent fibroblasts overproduce vimentin protein, and the overproduced vimentin filaments bring about the senescent cell morphology.

Purification and characterization of L-2,3-butanediol dehydrogenase of Brevibacterium saccharolyticum C-1012 expressed in Escherichia coli

The L-2,3-butanediol dehydrogenase produced in E. coli JM109/pLBD2-CTC was purified by 5 steps. The molecular mass of this enzyme was estimated at 110 kDa and the subunit was measured to be 30 kDa. The L-BDH had some differences from the BDHs from other sources in substrate specificity, pI value, pH stability, effects of divalent cations, and organic acids.

Stereochemical applications of the expression of the L-2,3-butanediol dehydrogenase gene in Escherichia coli

The L-2,3-butanediol dehydrogenase (L-BDH) gene of Brevibacterium saccharolyticum was strongly expressed in Escherichia coli using the tac promoter. However, the stereospecificity of the resulting L-BDH was reduced. The region upstream of the meso-BDH gene of Klebsiella pneumoniae was also involved in the expression of the B. saccharolyticum gene. However, in this case, the resulting L-BDH exhibited more stable stereospecificity. A stereospecificity recognition region was located within the rear sequence (Hpa I site, carboxy terminal) of the BDH open reading frame. Using a transformed strain of E. coli, the conversion of L-acetoin (L-AC), in the commercially available racemic mixture of AC, to L-2,3-butanediol (L-BD) was attempted. As a result, 0.37% L-BD was formed from 1% AC added to the culture.

Insulin resistance and angiotensin converting enzyme polymorphism in Japanese hypertensive subjects

Renin-angiotensin system activity has been shown to affect insulin sensitivity. However, the relationship between I/D polymorphism and insulin resistance is controversial. Therefore, we examined the relationship between the ACE genotype and insulin sensitivity in 51 Japanese hypertensive patients using the glucose clamp technique. The ACE genotype distribution in the hypertensive subjects was: 7 subjects with DD, 20 subjects with ID, and 24 subjects with II. Insulin sensitivity in terms of the glucose disposal rate was not significantly different among the three ACE genotypes, although there was a tendency for insulin sensitivity to decrease in the order of II, ID and DD, DD being the lowest. These findings are contrary to previous reports that insulin sensitivity was increased in normotensive subjects with the DD genotype who were Caucasian or African-American. There might be a difference due to race and whether the subjects are hypertensive or obese. We concluded that insulin sensitivity was not different among the ACE genotypes in the Japanese hypertensive subjects, supporting a previous report on the Chinese population. To date, insulin sensitivity has not been found to differ with ACE genotypes in the oriental population.

Formation of a chiral acetoinic compound from diacetyl by Escherichia coli expressing meso-2,3-butanediol dehydrogenase

L-Acetoin (L-AC) was produced from diacetyl (DA) by Escherichia coli JM109/pBUD119 containing the meso-2,3-butanediol dehydrogenase (D-AC forming) gene. However, when the strain was cultured in the presence of isopropyl-beta-D-thiogalacto-pyranoside, the enzyme formed catalysed not only D-AC but also L-AC. L-AC was further reduced to L-2,3-butanediol (BD). The yield of L-AC or L-BD from DA (3 gl-1) was about 70% (w/w).

Transcriptional regulation of adrenomedullin in rat vascular smooth muscle cells

Adrenomedullin (AM), a potent vasorelaxant peptide recently identified in extracts of pheochromocytoma, is actively secreted from vascular smooth muscle cells (VSMC). AM production in rat VSMC is potently stimulated by proinflammatory cytokines including TNF alpha, and glucocorticoids and many vasoactive substances have also been shown to alter AM synthesis. To study AM promoter function, we cloned the 5'-flanking region of the rat AM gene, and AM promoter function was assessed in rat VSMC stably transfected with a construct containing the cloned fragment. This 1.4 kb AM promoter region includes a number of putative transcriptional control elements. The promoter activity in VSMC was stimulated by TNF alpha and dexamethasone, and was suppressed by 8-bromo-cAMP and forskolin. These data indicate that transcriptional regulation is an important mechanism for AM production in VSMC.

Separation and properties of two acetylacetoin reductases from Bacillus cereus YUF-4

The separation and purification of two kinds of acetylacetoin reductases (AACRs) from Bacillus cereus YUF-4 were examined. NADPH-linked AACR (AACR I) and NADH-linked AACR (AACR II) were separated from each other by ammonium sulfate fractionation, DEAE-cellulose chromatography, and hydroxyapatite chromatography. The former was purified 3.4-fold with a yield of 10.0%, and the latter was purified 29-fold with a yield of 15.6%. The two enzymes differ from each other in some enzymic properties such as substrate specificity.

Purification and properties of acetylacetoin synthase from Bacillus sp. YUF-4

In Bacillus sp. YUF-4, acetylacetoin synthase was induced by acetoin, while glucose inhibited the induction. The enzyme was purified 111-fold by 6 purification steps, and a further purification followed, by HPLC using a TSK gel, Phenyl-5PW RP. The resulting enzyme gave a single band with a molecular mass of 62 kDa by SDS-PAGE and 220 kDa by gel filtration. Some enzymic characteristics were studied.

The production of D-acetoin by a transgenic Escherichia coli

A 6 kbp SphI fragment encoding genes for the enzymes alpha-acetolactate synthase (ALS), alpha-acetolactate decarboxylase (ALDC) and meso-2,3-butanediol dehydrogenase (meso-BDH), involved in the formation of meso-2,3-butanediol (meso-BD) from pyruvic acid, was cloned into plasmid pUC118. When derivatives of this plasmid were introduced into Escherichia coli JM109, the transformants were able to produce D-acetoin (D-AC) without contamination with L-acetoin (L-AC).

Effect of arotinolol on insulin sensitivity in obese hypertensive patients

Insulin sensitivity in terms of glucose disposal rate was determined by using the hyperinsulinemic euglycemic clamp technique in seven obese hypertensive patients and nine normotensive control subjects. The technique was used on all study subjects at baseline and on the hypertensive patients after 12 weeks of arotinolol treatment. Mean supine systolic blood pressure decreased from 155 +/- 3 mm Hg before treatment to 133 +/- 6 mm Hg after treatment (P < 0.02), and diastolic blood pressure decreased from 100 +/- 3 mm Hg before treatment to 86 +/- 3 mm Hg after treatment (P < 0.05). The mean dose of arotinolol was 10 mg/d, except for one patient who received 20 mg/d. The glucose disposal rate during the last 30 minutes of the glucose clamp procedure was not significantly affected by treatment with arotinolol. Compared with the hypertensive patients, the glucose disposal rate in the normotensive subjects was significantly increased, both before and after treatment (P < 0.01). The study results show that the obese hypertensive patients were insulin resistant and that treatment with arotinolol did not significantly affect insulin sensitivity.

Comparison of effects of nicardipine and trichlormethiazide on insulin sensitivity in hypertensive patients

We performed a randomized, crossover study comparing the effects of nicardipine and trichlormethiazide on insulin sensitivity in 8 untreated essential hypertensive patients. They were treated either with nicardipine or trichlormethiazide for 12 weeks, after which they were treated with the alternative drug for a further 12 weeks. Insulin sensitivity was determined by the hyperinsulinemic euglycemic clamp technique. Nicardipine had no adverse effect on insulin sensitivity. Trichlormethiazide decreased insulin sensitivity index by 12%. As nicardipine does not have an adverse effect on insulin sensitivity, it should be preferred in patients who have a proven metabolic abnormality.

Insulin sensitivity test using a somatostatin analogue, octreotide (Sandostatin)

To assess the validity of the steady-state plasma glucose (SSPG) method using octreotide (Sandostatin), we compared the SSPG method with the euglycemic hyperinsulinemic clamp technique in ten non-obese, insulin-dependent diabetic patients. The SSPG method was performed by intravenous infusion of octreotide (0.5 microgram/min), insulin (2 mU/kg/min) and glucose (9 mg/kg/min) for 180 min. Octreotide suppressed endogenous growth hormone, glucagon and insulin secretion. A steady state condition was reached by 90 min, and the mean value of SSPG at 150 and 180 min was used as the index of insulin sensitivity. The euglycemic hyperinsulinemic clamp technique was performed with an artificial endocrine pancreas (Biostator), and insulin sensitivity was expressed as the glucose disposal rate (GDR) from 150-180 min. There was a significant correlation (r = 0.91, p < 0.001) between the results of the two methods. In conclusion, measurement of SSPG, using octreotide to suppress endogenous insulin secretion, is a reliable method to assess insulin sensitivity in man.

Doxazosin improves insulin sensitivity in hypertensive patients

Insulin sensitivity in terms of glucose disposal rate was measured by the hyperinsulinemic/euglycemic clamp technique in 10 hypertensive patients and 7 normotensive control subjects before and after 12 weeks of doxazosin therapy. Supine blood pressure fell significantly, from 150/98 mmHg before treatment to 136/90 mmHg after treatment (systolic P < 0.001/diastolic P < 0.01). The average dose of doxazosin at the end of the study was 3.3 +/- 0.4 mg/day. The glucose disposal rate during the last 30 minutes of the glucose clamp procedure was significantly increased, from 5.8 +/- 0.7 mg/kg/min before to 7.8 +/- 0.7 mg/kg/min after treatment (P < 0.02). Insulin sensitivity was 8.7 +/- 0.4 mg/kg/min in the normotensive subjects, which represented a significant difference when compared with that of the hypertensive subjects before treatment (P < 0.01). Steady-state serum insulin concentrations, as measured during the glucose clamp procedure, were 172 +/- 10.4 microU/ml before and 176 +/- 13.5 microU/ml after doxazosin treatment; these levels were significantly higher than the 137 +/- 7.0 microU/ml reading obtained in the normotensive subjects (P < 0.05). Study results show that hypertensive patients tend to be insulin resistant and that treatment with doxazosin improves insulin sensitivity.

Inhibitory effect of 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8) on germination of Bacillus cereus T spores

Effect of 8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate hydrochloride (TMB-8), a calcium antagonist, on germination of Bacillus cereus T spores induced by L-alanine and inosine was investigated. TMB-8 had no effect on the germination of heat-activated spores, whereas it inhibited that of nonactivated spores. The TMB-8 inhibitory effect was antagonized competitively by inosine, but not by L-alanine. Addition of Ca2+ reversed the inhibitory effect of TMB-8 in a dose-related fashion. Based on the results, a role of inosine and a site(s) for inhibitory action of TMB-8 in the process leading to the germination of nonactivated spores were discussed.

[Role of growth hormone in the pathogenesis of dawn phenomenon in IDDM]

The early morning hyperglycemia of diabetic patients has been commonly referred to as the "dawn phenomenon". Recently the nocturnal surges of growth hormone (GH) have been suggested as an important factor in the pathogenesis of the dawn phenomenon. In order to reassess the role of the nocturnal GH secretion in the dawn phenomenon, seven C-peptide negative diabetic patients were studied during 48hr-feedback control using a closed-loop insulin infusion device (Biostator). They received oral sleeping medication only on the first night (control) and sleeping medication with anticholinergic agent (pirenzepine 75mg) on the second night, and blood glucose, insulin requirements, GH and cortisol concentrations during 0000hr and 0700hr were measured. The peak of sleep-induced GH secretions was markedly suppressed by pirenzepine in comparison with the control night (19.8 +/- 3.7 vs. 3.0 +/- 1.2ng/ml; p less than 0.05). Insulin requirements during 0500hr and 0700hr were suppressed significantly by pirenzepine (3.0 +/- 0.2 vs. 2.0 +/- 0.2U/2hr; p less than 0.05). Insulin infusion ratio, i.e. insulin requirements during 0500hr and 0700hr divided by those during 0000hr and 0200hr, was decreased by pirenzepine (2.2 +/- 0.3 vs. 1.5 +/- 0.2; p less than 0.05). There were no significant differences in blood glucose and cortisol concentrations whether or not the anticholinergic agent was given. In conclusion, these results have shown that an anticholinergic agent may be useful in the management of insulin-treated patients with marked dawn phenomenon.

[Regional distribution of sulfatide in human kidney, and anti-sulfatide antibodies in sera from patients with nephritis detected by TLC immunostaining]

Glycolipids were isolated from lipid extract of human kidney. The major neutral glycolipids have been identified as ceramide monohexoside (CMH), ceramide dihexoside (CDH), ceramide trihexoside (CTH), and globoside. As the major acidic glycolipids, Gal Cer sulfate (sulfatide), Lac Cer sulfate, GM3, sialosyl paragloboside, GD3, and disialosyl paragloboside were identified and the most abundant component was sulfatide. Sulfatide was 2 times more concentrated in medulla compared to cortex. In addition, the localization of sulfatide antigen was determined in renal sections by immunoperoxidase staining method. Strong positive staining with sulfatide was observed in distal tubules, limbs of Henle's loop and collecting tubules of normal tissue, whereas glomeruli were negative of staining. However, positive results of glomerular epithelial cells occurred in FSGS and IgA nephropathy so far. Acidic fraction of lipid extract were chromatographed and then tested for antigen by immunostaining. Sera from patients with nephritis contain antibodies to the sulfatides of human kidney as determined by the direct binding of antibody to thin-layer chromatograms. These results suggest that sulfatide antigen may play important role in the occurrence and aggravation of glomerular diseases.

[An autopsied case of insulin dependent diabetes mellitus complicated by chronic thyroiditis and chronic hepatitis]

A deceased 59-year-old woman with insulin dependent diabetes mellitus complicated by chronic thyroiditis and chronic hepatitis was autopsied. She had had diabetes mellitus since she was 30 years old, and insulin therapy was started at 34 years. Laboratory findings were as follows: s-GOT 85, s-GPT 31, gamma-globulin 2.45 g/dl. Immunological tests were positive for anti-smooth muscle antibody and anti-ENA antibody with high titers of antithyroglobulin and anti-microsome antibodies. HLA analysis revealed the presence of DR-4. The thyroid biopsy specimen showed microscopic features characteristic of chronic thyroiditis at 52 years of age. She had been repeatedly admitted for the control of diabetes mellitus. She was admitted for the 9th time in June, 1987 following complaints of abdominal pain. After admission, her general condition became gradually worse, and she died of peritonitis in September, 1987. Pathological examination of the liver revealed an expansion of fibrous tissue on Glisson's capsule accompanied by lymphocytic infiltration and was diagnosed to be chronic inactive hepatitis. As for the thyroid gland, fibrous tissue replaced an extensive area of the thyroid gland, and normal thyroid tissue was not observed. Lymphocytic infiltration was less in comparison with that in the previous biopsy. As for the pancreas, atrophy of exocrine pancreatic tissue and fibrous change in interstitial tissue was observed. Lymphocytic infiltration was also seen in the interstitial exocrine tissue but not in the islet. Immunohistochemical examination of the islets using anti-insulin, glucagon and somatostatin antibodies by ABC peroxidase method showed the selective disappearance of B cells in the islets. The pathological changes in the thyroid gland, liver and pancreas suggest that autoimmune mechanism may be involved in the pathogenesis of chronic thyroiditis, chronic hepatitis and IDDM with exocrine pancreatic impairment in this case.

A growth-promoting factor for human myeloid leukemia cells from horse serum identified as horse serum transferrin

A growth-promoting factor for human myeloid cells was purified to apparent homogeneity from horse serum by a combination of gel filtration, blue Sepharose affinity chromatography, Mono Q anion-exchange chromatography, Mono P chromatofocusing and sodium dodecyl sulfate polyacrylamide gel electrophoresis. The growth promoter was an iron-bound, single glycopolypeptide chain with a molecular weight of 84,000, an isoelectric point of 5.4 and an amino terminal sequence of Glu-Gln-Thr-Val-Arg-Trp-Cys-Thr-Val-Ser-Asn-His-Glu-Val-Ser-Lys-. According to the results of the amino acid sequence, iron binding ability and physicochemical properties, we identified the growth-promoting factor as horse serum transferrin. It was highly active in promoting the proliferation of a human monocytic leukemia cell line, THP-1, as well as of two other human myeloid cell lines, HL-60 and K-562. It had the same activity in proliferating THP-1 cells as 5% fetal calf serum-supplemented medium. Horse serum transferrin could be substituted for human or bovine serum transferrin.