Practical applications in molecular biology of sensitive fluorescence detection by a laser-excited fluorescence image analyzer

A new kind of fluorescence image analyzer was developed for a variety of uses, especially in molecular biology. Compounds labeled with fluorescent groups on a gel or nitrocellulose membrane are excited with 532 nm of light from a green laser. The fluorescence emitted passes through light-collecting fibers to a photomultiplier. Imaging data converted from the emitted light are analyzed by a microcomputer and stored on a magnetic optical disk. Dideoxy DNA sequencing was done with the same amount of DNA used for autoradiography, and the sequencing ladders obtained from gel scanning were automatically converted to sequence data by the analyzer. When an agarose gel was analyzed after electrophoresis, DNA stained with ethidium bromide was detected by the analyzer with higher sensitivity rather than by the conventional photographic method. Nylon and nitrocellulose membranes could be read by the analyzer, so blot hybridization experiments can be done without radioisotopes. High-quality computer storage of the imaging data from gel electrophoresis and hybridized membranes, including pulsed-field gels, make it possible to quantify image intensity and to construct many kinds of databases.

[Assessment of cardiac function and left ventricular regional wall motion by 99mTc multigated cardiac blood-pool emission computed tomography]

Forty-three patients underwent the analysis of left and right ventricular (LV and RV) volumes, and LV regional wall motion by multigated cardiac blood pool single photon emission computed tomography (SPECT) with 99mTc. To calculate the cardiac volume correctly, the optimal cutoff level in relation to background level was first obtained by a phantom study. Left ventricular end-diastolic, end-systolic volume (EDV and ESV) and ejection fraction (EF) calculated thus with SPECT were correlated well with the data obtained with left ventriculography (LVG) and magnetic resonance imaging (MRI), especially using horizontal long axial image. RV stroke volume (SV) without shunt or valvular diseases was also correlated well with that of LV when it was calculated using horizontal long axial image. However, SV ratio (LVSV/RVSV) was not necessarily ideal numerical 1. In addition LV wall motion was evaluated by multicontour systolic display and phase analysis in SPECT and gated planar images. The results obtained with SPECT were better correlated with those of LVG than gated planar images. It is concluded that multigated cardiac blood pool SPECT is a clinically useful method for an evaluation of cardiac function and left ventricular regional wall motion.

Organization and nucleotide sequence of the glutamine synthetase (glnA) gene from Lactobacillus delbrueckii subsp. bulgaricus

A 3.3-kb BamHI fragment of Lactobacillus delbrueckii subsp. bulgaricus DNA was cloned and sequenced. It complements an Escherichia coli glnA deletion strain and hybridizes strongly to a DNA containing the Bacillus subtilis glnA gene. DNA sequence analysis of the L. delbrueckii subsp. bulgaricus DNA showed it to contain the glnA gene encoding class I glutamine synthetase, as judged by extensive homology with other prokaryotic glnA genes. The sequence suggests that the enzyme encoded in this gene is not controlled by adenylylation. Based on a comparison of glutamine synthetase sequences, L. delbrueckii subsp. bulgaricus is much closer to gram-positive eubacteria, especially Clostridium acetobutylicum, than to gram-negative eubacteria and archaebacteria. The fragment contains another open reading frame encoding a protein of unknown function consisting of 306 amino acids (ORF306), which is also present upstream of glnA of Bacillus cereus. In B. cereus, a repressor gene, glnR, is found between the open reading frame and glnA. Two proteins encoded by the L. delbrueckii subsp. bulgaricus gene were identified by the maxicell method; the sizes of these proteins are consistent with those of the open reading frames of ORF306 and glnA. The lack of a glnR gene in the L. delbrueckii subsp. bulgaricus DNA in this position may indicate a gene rearrangement or a different mechanism of glnA gene expression.

Aphidicolin inhibits DNA polymerizing activity but not nucleolytic activity of Escherichia coli DNA polymerase II

We have purified the DNA polymerase II of Escherichia coli from the recombinant strain carrying the plasmid which encodes the polB gene. We confirmed that the purified protein, of molecular weight 90,000, possesses a 3'----5' exonuclease activity in addition to DNA polymerizing activity in a single polypeptide. Its DNA polymerizing activity was sensitive to the drug aphidicoline, which is a specific and direct inhibitor of the alpha-like DNA polymerases including eukaryotic replicative DNA polymerases. Aphidicolin had no detectable effect on the 3'----5' exonuclease activity. The inhibition by aphidicolin on the polymerizing activity of polymerase II was competitive with respect to dNTP and uncompetitive with respect to template DNA. This mode of action is the same as that on eukaryotic DNA polymerase alpha. The apparent Ki value calculated from Lineweaver-Burk plots was 55.6 microM.

Escherichia coli DNA polymerase II is homologous to alpha-like DNA polymerases

The Escherichia coli polB gene encodes DNA polymerase II and is regulated by the SOS system. We sequenced a 4081 nucleotide segment of the E. coli chromosome that contains the polB gene and its flanking regions. DNA polymerase II, as deduced from the DNA sequence, consists of 782 amino acids, has a molecular weight of 89,917, and is structurally homologous to alpha-like DNA polymerases, which include eukaryotic replicative DNA polymerases. Comparison of the sequences of the alpha-like DNA polymerases including E. coli DNA polymerase II showed that there were nine highly conserved regions, and we constructed an unrooted phylogenetic tree of the DNA polymerases based on the differences in these conserved regions. The DNA polymerases of herpes groups viruses and the DNA polymerases that use protein priming for the initiation of replication form two separate subfamilies that occupy opposite locations in the tree. Other DNA polymerases, including E. coli DNA polymerase II, human DNA polymerase alpha, and yeast DNA polymerase I, occupy the central regions between the two subfamilies and they are rather distantly related to each other. The transcription initiation site of polB was identified by analysis of in vivo transcripts, and the promoter was assigned upstream of the polB coding region. The recognition sequence of the LexA repressor (SOS box) was identified by a footprinting experiment. It overlaps the -35 sequence of the polB promoter.

SOS-inducible DNA polymerase II of E coli is homologous to replicative DNA polymerase of eukaryotes

The polB gene of Escherichia coli encodes DNA polymerase II whose role in vivo is not defined. The polB gene has been cloned and shown to be identical to a DNA damage-inducible gene dinA which is regulated by the LexA repressor. Nucleotide sequencing of polB reveals that E coli DNA polymerase II is highly homologous to replicative DNA polymerases of eukaryotes which include human DNA polymerase alpha and Saccharomyces cerevisiae DNA polymerases I, II and III. The polB gene is not required for growth, UV-repair and UV-mutagenesis.

[The efficacy of bone scintigraphy screening in postoperative follow-up of breast cancer patients]

Discussed are 110 breast cancer patients given surgery, totaling 70 stage 1 cases, 22 stage II cases, 15 stage III cases, and 3 stage IV cases, that were routinely followed-up postoperatively at 6 or 12-month intervals, said follow-ups including bone scintigraphy screening. Among 394 bone scintigrams taken of these 100 patients, 15 new cases of a bone metastasis were detected, 9 of which had either a local recurrence or an associated metastasis at the time that their bone metastasis was detected. In only 1 case, at more than five years after surgery, was a bone metastasis detected by bone scintigraphy, and even this case had another metastasis at that time. Therefore, the value of bone scintigraphy screening as part of the follow-up of postoperative breast cancer patients is questioned.

[Radiation therapy and diagnosis of primary malignant lymphoma of the brain]

CT findings and the results of radiotherapy were retrospectively evaluated on 11 patients with primary malignant lymphoma of the brain treated at UOEH Hospital from November, 1979 to March, 1989. CT mostly showed an isodensity or slightly high-density round masses with marked contrast enhancement and was useful both for an initial diagnosis and an evaluation of the response following treatment. Radiation therapy was given to the whole brain in 9 patients. Two patients were irradiated only locally to the tumor bearing area, but no long-term effect was observed. The total dosage ranged from 30 to 51.2 Gy. The 8 patients who received 50 Gy or more to the tumors had higher survival and local control rates than the other 3 who received less than 40 Gy. We conclude that whole brain irradiation with at least a total dose of 50 Gy to the tumor area is necessary to control malignant lymphoma of the brain.

Purification and functional characterization of the Glu-tRNA(Gln) amidotransferase from Chlamydomonas reinhardtii

The formation of glutaminyl-tRNA (Gln-tRNA) in Bacilli, chloroplasts, and mitochondria occurs in a two-step reaction. This involves misacylation of tRNA(Gln) with glutamate by glutamyl-tRNA synthetase and subsequent amidation of Glu-tRNA(Gln) to the correctly acylated Gln-tRNA(Gln) by a specific amidotransferase (Schön, A., Kannangara, C. G., Gough, S., and Söll, D. (1988) Nature 331, 187-190). Here we demonstrate the existence of this pathway in green algae and describe the purification of the Glu-tRNA(Gln) amidotransferase from Chlamydomonas reinhardtii. The purified enzyme showed an Mr of approximately 120,000 when analyzed by glycerol gradient sedimentation and gel filtration. An apparent Mr of 63,000 of the denatured protein was demonstrated by electrophoresis on sodium dodecyl sulfate-polyacrylamide gels. This indicates that the enzyme possesses an alpha 2 structure. The substrate for the purified enzyme is Glu-tRNA(Gln) but not Glu-tRNA(Glu). The enzyme requires ATP, Mg2+, and an amide donor for the conversion. Acceptable amide donors are glutamine, asparagine, and ammonia. Blocking of the glutamine-dependent reaction by alkylation of the protein with 6-diazo-5-oxonorleucine did not inhibit the ammonia-dependent reaction, suggesting that the enzyme has separate glutamine and ammonia binding sites. As suggested by Wilcox (Wilcox, M. (1969) Eur. J. Biochem. 11, 405-412) the amidation reaction may involve glutamyl-phosphate formation, since ATP is cleaved to ADP when the enzyme is incubated with Glu-tRNA(Gln) and ATP. In common with other glutamine amidotransferases, the enzyme also possesses low glutaminase activity. The purified Glu-tRNA(Gln) amidotransferase forms a stable complex with Glu-tRNA(Gln) in the presence of ATP and Mg2+ but in the absence of the amide donor as determined by gradient centrifugation.

[Chemotherapeutic strategy in rat brain tumor cells resistant to ACNU using an in vitro colony formation assay]

Nitrosourea compounds have been widely used in the chemotherapy of malignant brain tumors, because of their blood-brain barrier permeability. However, drug resistance to nitrosoureas has been recently a major concern. Using an in vitro colony formation assay, intrinsic and acquired resistances to an anticancer nitrosourea, 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU), were analyzed in rat 9L and C6 glioma cells. 9L and C6 cells were treated with varying doses of ACNU for 2 hours. Ten days after, the cells were fixed and stained with crystal violet. Colonies consisting more than 50 cells were counted. The survival fraction following treatment is the ratios of colony efficiency of treated cells to the colony efficiency of untreated control cells. The dose-response curve for ACNU indicated the existence of a shoulder (Dq, quasithreshold dose) at doses and an exponential cell-killing at higher doses with D0(37% survival dose). Based on dose-response curves corresponding to multitarget single-hit model, 9L cells showed 7.4 microM, 2.9 microM, and 14 microM at Dq, D0, and SD10 (10% survival dose) values, respectively, whereas C6 cells showed respective values of 6.4 microM, 30 microM, and 75 microM. 9L cells had significantly less intrinsic resistance to ACNU than C6 cells at the p less than 0.005 level by a covariance analysis of the curves. As with changes of drug susceptibility after ACNU treatment, both parent cells were treated every other day (1, 5, and 10 repeated times) with various doses up to approximately 1% survival dose of the parent cells.(ABSTRACT TRUNCATED AT 250 WORDS)

[Computed tomography of calcaneal fractures--comparison with conventional radiography]

Computed tomography (CT) and conventional radiography were compared in 52 calcaneal fractures. As for CT, direct coronal imagings were performed in all and direct axial imagings were added in 27 of them. Conventional radiography included lateral, axial, and Anthonsen (oblique) views. Overall CT detected 7 more of the incongruity of the posterior facet, 9 more of the bulging of the lateral wall, and 6 more of the fracture of the sustentaculum tali than conventional radiography. In addition the entrapment of the peroneal tendons between the calcaneal body and the fibular malleolus could be evaluated only with CT. These informations are indispensable for the proper treatment of the fractures and we conclude that CT is useful in evaluating calcaneal fractures.

Microspectrofluorometric evaluation of single- and double-stranded DNA in short-term cultured human glioma cells

Seven cerebral gliomas in short-term culture were studied by microspectrofluorometry and acridine orange staining to assess their nuclear content of single- and double-stranded DNA. Benign gliomas showed a diploid DNA pattern, whereas malignant gliomas revealed a higher frequency of DNA aneuploidy and hyperploidy. The content of single-stranded DNA remained relatively low in benign gliomas; however, that in malignant gliomas varied widely. After ACNU treatment, the double-stranded DNA histograms showed S-phase-specific accumulation in all cases but 1 with increasing concentrations of ACNU. The single-stranded DNA content decreased considerably in 2 cases, which responded well to chemotherapy and showed clinical amelioration.

[Circumvention of ACNU-resistance in rat glioma cells by pretreatment with O6-methylguanine]

The chemotherapy of malignant brain tumors has been, only partially successful yet. Recently major concern is drug resistance, one of possible mechanisms of such drug resistance stems from inducible repair enzyme, especially in case of chloroethylnitrosoureas as ACNU or BCNU. We examined the changes of acquired resistance to ACNU in rat glioma cells by pretreatment with O6-methylguanine, which is a substrate for O6-methylguanine methyltransferase. ACNU-resistant (9L/AC) cells had established after 10 times treatments of ACNU. 9L/AC cells were pretreated with 2 mM O6-methylguanine for 2 hours, and subsequently challenged with increasing doses of ACNU for 2 hours. In vitro colony formation assay the survival fraction of 9L and 9L/AC cells ranged from 0.39 to 0.63 by 2-hour reaction of 1-3 mM O6-methylguanine. Based on the dose-response curve for ACNU in 9L/AC cells, by O6-methylguanine pretreatment (2 mM), ACNU-resistance decreased markedly to one-third, one-fifth, and one-two hundredth at 12, 24, 36 microM ACNU, respectively. In contrast, the survival of 9L cells against ACNU was similar under O6-methylguanine pretreatment or nontreatment condition. Therefore, ACNU-resistance is considerably related to DNA repair enzyme induction, and the substrates may potentiate the cell-killing effect of ACNU in the resistant glioma cells.

Arteriovenous malformation of the pancreas associated with mesenteric varices: case report and review of the literature

A 53-year-old man with an arteriovenous malformation of the pancreas associated with extensive mesenteric varices, liver cirrhosis, and hepatocellular carcinoma with arterioportal shunting was diagnosed by angiography. This is the first report of such a case with portal hypertension.

cDNA cloning of human calpastatin: sequence homology among human, pig, and rabbit calpastatins

cDNA of human calpastatin, an inhibitor protein specific for calpain (EC 3.4.22.17; Ca2(+)-dependent cysteine proteinase) was isolated by screening of a library prepared from human liver mRNA with pig calpastatin cDNA fragment as a probe. The primary structure of human calpastatin was deduced from the nucleotide sequence of the cDNA and compared with that of pig and rabbit calpastatins already reported. Human calpastatin consisted of 673 amino acid residues and had 78% and 77% identity to pig or rabbit calpastatins, respectively. Human calpastatin had a domain structure with four internally repetitive sequences and one N-terminal non-homologous sequence like the other calpastatins. Human calpastatin had two deletions, 22 and 13 residues long in domain L and domain 1, respectively, compared to pig or rabbit calpastatins.

[State III large cell carcinoma of the lung cured by radiotherapy--a case report]

Presented is the case of a 61-year-old male whose chief complaints were hoarseness, cough, and bloody sputum. Chest radiography demonstrated a left hilar mass with mediastinal widening, a peripheral localized infiltrate and the elevation of the left hemidiaphragm. By means of a mediastinoscopy, a biopsy was done on the enlarged mediastinal lymph node and a histological diagnosis of a large cell carcinoma was confirmed. He was graded as in Stage III (T2N2M0) and was placed under radiotherapy with 60Co. Complete response was obtained after a total dose of 6150 cGy. Following this radiotherapy, he was given multiple courses of mild chemotherapy and the disease as of this report has been under control for 7 years. This case may be unusual, but suggests the possibility of a cure of lung cancer by irradiation under certain conditions.

Unusual bone scintigraphy in chronic myelogenous leukemia--report of a case showing extensive uptake defect

An extensive 99mTc-methylene diphosphonate uptake defect was observed on bone scintigraphy in a 35-year-old male with chronic myelogenous leukemia. This type of bone scintigraphy pattern is quite unusual in leukemic patients and we speculate that acute disturbance of blood supply to the bone marrow was probably the cause.

[Analysis of DNA damage induced by nitrosourea derivatives in rat brain tumor cells using a sequencing procedure]

DNA damages caused by various anticancer nitrosourea compounds such as ACNU and MCNU were studied. Reiterated fragments of 167 and 203 base pairs (bp) were obtained after Hind III and Hae III restriction endonuclease digestion of 9L rat brain tumor DNA. The end-labeled reiterated fragments were reacted with ACNU and MCNU, which resulted in the scission breaks corresponding to the locations of guanine on an extended Maxam-Gilbert sequencing gel. Subsequent piperidine hydrolysis yielded scission products more frequently. These results indicate that nitrosoureas such as ACNU and MCNU generate DNA scission breaks and/or alkali-labile sites preferentially at the position of guanine moieties in rat brain tumor DNA.

Nucleotide sequence of the iap gene, responsible for alkaline phosphatase isozyme conversion in Escherichia coli, and identification of the gene product

The iap gene in Escherichia coli is responsible for the isozyme conversion of alkaline phosphatase. We analyzed the 1,664-nucleotide sequence of a chromosomal DNA segment that contained the iap gene and its flanking regions. The predicted iap product contained 345 amino acids with an estimated molecular weight of 37,919. The 24-amino-acid sequence at the amino terminus showed features characteristic of a signal peptide. Two proteins of different sizes were identified by the maxicell method, one corresponding to the Iap protein and the other corresponding to the processed product without the signal peptide. Neither the isozyme-converting activity nor labeled Iap proteins were detected in the osmotic-shock fluid of cells carrying a multicopy iap plasmid. The Iap protein seems to be associated with the membrane.

[Bone scintigraphy in bone metastases due to prostatic cancer]

Findings of bone scintigraphy with 99mTc-MDP were compared with bone radiography and biochemical data including total acid phosphatase (T. ACP), prostatic acid phosphatase (P. ACP), and alkaline phosphatase (ALP) in 35 patients with histologically proven prostatic cancer. Bone metastases were diagnosed in 20 of 35 cases (57%) by scintigraphy. The common sites of metastases were the pelvic bones, ribs, lumbar and thoracic vertebrae. In vertebrae, metastases were mainly distributed in the lower level. The most frequent radiographic change due to metastases was the osteoblastic type. On follow-up studies, there was a relatively good agreement in the results of bone scintigraphy and radiography. However, there was a good number of cases showing discrepancy between either scintigraphy or radiography and laboratory data. Bone scintigraphy seems to be the most contributory in monitoring bone metastases from prostatic cancer.

Nucleotide sequence of the lig gene and primary structure of DNA ligase of Escherichia coli

The DNA ligase of Escherichia coli catalyses the NAD-dependent formation of phosphodiester linkages between 5'-phosphoryl and 3'-hydroxyl groups in DNA. It is essential for DNA replication and repair of damaged DNA strands. We determined the nucleotide sequence of the lig gene of Escherichia coli coding for DNA ligase and flanking regions. The coding frame of the gene was confirmed by the amino acid composition and the amino- and carboxyl-terminal amino acid sequences of the purified ligase. The ligase consists of 671 amino acid residues with a molecular weight of 73,690.

OMNIPOTENT SUPPRESSORS EFFECTIVE IN Ψ+ STRAINS OF SACCHAROMYCES CEREVISIAE: RECESSIVENESS AND DOMINANCE

We have characterized recessive and dominant omnipotent suppressor mutations obtained by conversion of the leu2-1 UAA mutation and the met8-UAG mutation in a ψ+ strain of Saccharomyces cerevisiae. The suppressors that act recessively upon these markers fell into two complementation groups; the sup47 and sup36 suppressors show linkage to the tyr1 locus and the aro1 locus, respectively. Of the suppressors acting dominantly upon both markers, those linked to the tyr1 locus are alleles of the SUP46 ribosomal mutation. The sup47 suppressors differ from the SUP46 suppressors not only in their suppressor activities in heterozygous diploids but also in their map positions relative to the tyr1 locus and their effects on the S11 ribosomal protein. The remaining dominant suppressors are not alleles of sup36 as judged by linkage analysis. The recessive suppressors and the dominant suppressors also differ in their effects on cell growth.

Recognition by restriction endonuclease EcoRI of deoxyoctanucleotides containing modified sugar moieties

The deoxyribooctanucleotide d(G-G-A-A-T-T-C-C), containing the recognition sequence for EcoRI, d(G-A-A-T-T-C), and analogs containing modified sugar moieties were tested for their activity in cleavage with EcoRI. These analogs, with replacement in the third position from the 5' end, were synthesized using 9-beta-D-arabinosyladenine (aA), 2'-deoxy-2'-fluoroadenosine (Afl) and adenosine (rA). Duplex formation by the three analogs was confirmed by measurements of ultraviolet/temperature profiles. It was found that EcoRI cleaved these duplexes less efficiently than d(G-G-A-A-T-T-C-C). The adenosine-containing analog d(G-G)-rA-d(A-T-T-C-C) was cleaved much more slowly than d(G-G)-aA-d(A-T-T-C-C) and d(G-G-Afl-A-T-T-C-C). The corresponding ribooctamer G-G-A-A-U-U-C-C showed a higher melting temperature than the deoxyoctamers but its duplex was not cleaved by this enzyme. An analog with 2'-deoxy-2'-fluoroguanosine at the second position was cleaved by the endonuclease faster than the natural deoxyoctamer.

Nonsense mutations in the can1 locus of Saccharomyces cerevisiae

Yeast mutants resistant to L-canavanine were selected. All were recessive and fell into the can1 complementation group. Nonsense mutations were identified among them by using a set of different suppressors. Frequencies of UAA, UAG, and presumed UGA mutations were 14.8, 0.8, and 0.4%, respectively. A high incidence of nonsense mutations having discriminatory suppression patterns was characteristic of the locus.

Recessive UAA suppressors of the yeast Saccharomyces cerevisiae

Recessive lysine-independent revertants were isolated from a psi + haploid strain of the yeast Saccharomyces cerevisiae containing one of the leucine-inserting UAA suppressors, SUP29, and various UAA mutations including lys1-1. The majority of the revertants were found to have recessive suppressors in addition to the pre-existing SUP29 mutation. The recessive suppressors were able to suppress only a very limited number of UAA mutations, and none of the UAG mutations thus far examined. The recessive inefficient UAA suppressors were assigned to three complementation groups, sup111, sup112, and sup113. A high incidence of gene conversion was observed for an allele of sup111. An antisuppressor acting on sup111, but not detectably on SUP29, was inadvertently obtained during the course of the study. Interactions between SUP29, sup111 and the antisuppressor asu12 were studied.

Coupling factor F1 ATPase with defective beta subunit from a mutant of Escherichia coli

The defective coupling factor F1 ATPase from a mutant strain (KF11) of Escherichia coli was purified to a practically homogeneous form. The final specific activity of Mg2+-ATPase was 6-9 units/mg protein, which is about 10-15 times lower than that of F1 ATPase from the wild-type strain. The mutant F1 had a ratio of Ca2+-ATPase to Mg2+-ATPase of about 3.5, whereas the wild-type F1 had ratio of about 0.8. The mutant F1 was more unstable than wild-type F1: on storage at -80 degrees C for 2 weeks, about 80% of its activity (dependent on Ca2+ or Mg2+) was lost, whereas none of the activity of the wild-type F1 was lost. The following results indicate that the mutation is in the beta subunit. (i) High Mg2+-ATPase activity (about 20 units/mg protein) was reconstituted when the beta subunit from wild type F1 was added to dissociated mutant F1 and the mixture was dialyzed against buffer containing ATP and Mg2+. (ii) Low ATPase activity having the same ratio of Ca2+-ATPase to Mg2+-ATPase as the mutant F1 was reconstituted when a mixture of the beta subunit from the mutant F1 and the alpha and gamma subunits from wild-type F1 was dialyzed against the same buffer. (iii) Tryptic peptide analysis of the beta subunit of the mutant showed a difference in a single peptide compared with the wild-type strain.