Two new genes, PHO86 and PHO87, involved in inorganic phosphate uptake in Saccharomyces cerevisiae

The PHO84 gene in Saccharomyces cerevisiae encodes a Pi transporter, mutation of which confers constitutive synthesis of repressible acid phosphatase (rAPase), in medium containing repressible amounts of Pi, and an arsenate-resistant phenotype. We selected an arsenate-resistant mutant showing the constitutive synthesis of rAPase on nutrient plates containing 4.5 mM arsenate. This mutant has double mutations designated as pho86 and pho87. The mutant transcribes PHO84 even in the repressible condition but has a severe defect in Pi uptake. The constitutive rAPase+ phenotype of the pho86 pho87 mutant was partially suppressed by an increased dosage of the PHO84 gene. The PHO87 gene was found to be identical with YCR524, according to the published nucleotide sequence of chromosome III, which encodes a protein of 923 amino-acid residues with a highly charged N-terminal half followed by a C-terminal half consisting of 12 membrane-spanning segments as in Pho84p. These and the other findings suggest that the Pho86p and Pho87p proteins collaborate with Pho84p in Pi uptake.

Staged repair of tetralogy of Fallot and pulmonary atresia without central pulmonary arteries

A 15-year-old boy with tetralogy of Fallot and pulmonary atresia without central pulmonary arteries who was successfully treated using a staged approach is presented. The first stage consisted of the creation of central pulmonary arteries. In the second stage, the continuity between the right ventricle and the pulmonary arteries was established with closure of the ventricular septal defect. Some patients previously considered to be unsuitable candidates for correction may be successfully repaired using this approach.

Structure and distribution of specific cis-elements for transcriptional regulation of PHO84 in Saccharomyces cerevisiae

Transcription of the PHO84 gene encoding a Pi transporter in Saccharomyces cerevisiae is regulated by the Pi concentration in the medium. The promoter region of PHO84 bears five copies of the motif 5'-CACGT(G/T)-3', a candidate for the upstream activation site (UAS) that binds the transcriptional activator protein of the phosphatase regulon, Pho4p. These motifs are found at nucleotides -880 (site A), -587 (B), -436 (C), -414 (D), and -262 (E) relative to the putative ATG codon of PHO84. The Pho4p binds to all five 6-bp motifs with various affinities. Deletion analysis of the PHO84 promoter using a PHO84-lacZ fusion gene and base substitutions in the 6-bp motif revealed that two copies of the 6-bp motif, either C or D, and E, are necessary and sufficient for full regulation of the PHO84 gene. Results of expression studies with a CYC1-lacZ fusion gene with various 36-bp oligonucleotides including the 30-bp sequences around site D or E, or with modified sequences, inserted in the CYC1 promoter region indicated that the 6-bps motif flanked by a thymine nucleotide at its 5' end is much less effective as a UAS site for Pho4p in vivo than other versions. Thus, the consensus sequences for phosphatase regulation are 5'-GCACGTGGG-3' and 5'-GCACGTTTT-3' which differ from the binding sequences for the Cpflp protein required for transcription of the genes in methionine biosynthesis and for centromere function. However, Pho4p binding in vitro was unaffected by modification of the 5' or 3' flanking sites of the 6-bp motif, while modification inside the 6-bp motif affected it severely. The UAS function of the GCACGTTTT motif with respect to the Pi signal depends on its orientation in the promoter sequence.

Optimization of rice alpha-amylase production using temperature-sensitive mutants of Saccharomyces cerevisiae for the PHO regulatory system

A typical example of rational system synthesis for bioproduction by the cultivation of microorganisms harboring a recombinant plasmid was studied. First, two temperature-controllable expression systems for a foreign gene in Saccharomyces cerevisiae were constructed. The promoter of the PHO84 gene, which encodes an inorganic phosphate (Pi) transporter of S. cerevisiae and is controlled by Pi concentration through the PHO regulatory system, was used. And two temperature-sensitive mutants of S. cerevisiae for the PHO regulatory system were used as the host with rice alpha-amylase expression vector. One was temperature-sensitive pho81 mutant, SH3337, and the other was temperature-sensitive pho80 mutant, YKU107. When the strain SH3337 is cultivated at a lower temperature, the rice alpha-amylase gene connected downstream of the PHO84 promoter is expressed, but at a higher temperature, it is not. Conversely, with the strain YKU107, the transcription of the rice alpha-amylase gene is induced at a higher temperature and repressed at a lower one. The optimal cultivation temperature strategies for maximum production of rice alpha-amylase in batch cultures of these two recombinant strains were then determined by the Maximum Principle using the relationships of the specific growth and specific production rates to the cultivation temperature. The optimal strategies were easy to realize and were shown to be effective for maximum product. Finally, under these maximum alpha-amylase production strategies, the alpha-amylase activities and alpha-amylase yields in terms of glucose consumption for these recombinant strains were calculated on the basis of experimental data and compared for various operation times. The study demonstrates how a foreign gene expression system can be synthesized using a temperature-sensitive mutant with a given objective and under given constraints.

[A case of Ebstein's anomaly treated by tricuspid valve replacement]

A 8-year-old girl with Ebstein's anomaly was operated on because of progressive heart failure caused by severe tricuspid regurgitation. At the operation, the tricuspid leaflets were found to be destroyed, and the annulus was very enlarged. The enlarged true tricuspid annulus was constricted using the DeVega method, and the tricuspid valve was replaced on the true annulus using a porcine valve. To avoid injury to the auriculoventricular bundle, the suture line was shifted to the false annulus at the portion close to the course of His' bundle. Postoperative course was uneventful in satisfactory condition. The role of valve replacement in the treatment of Ebstein's anomaly of the tricuspid valve is not only to improve valve formation, but also to secure the function of the right ventricle. It is ideal to replace the tricuspid valve on the true annulus provided that the injury to the His' bundle is safely avoided.

[A diabetic patient with bilateral carotid stenosis who developed neovascular glaucoma following cataract surgery]

A 67-year-old diabetic man suffered from right neovascular glaucoma following the ipsilateral cataract surgery. Three years later, he underwent left cataract surgery and again developed left neovascular glaucoma after the operation. Fluorescein angiogram showed a marked delay in retinal circulation. Moreover, severe stenosis of bilateral carotid origins and reflux of bilateral ophthalmic arteries were ascertained by neurosonographical examination such as duplex cervical echography and transcranial Doppler, as well as an angiogram. Brain imaging demonstrated asymptomatic watershed infarction in the left parieto-occipital cortex. Chronic ocular ischemia caused by carotid stenosis is one of the decisive risk factors for secondary glaucoma after cataract surgery. Preoperative neurosonographical screening tests are required to decrease ocular surgery complications, especially in the aged, and diabetic patients.

[Multiple myeloma developing myelodysplastic syndrome with thrombocytosis]

A 64-year-old woman with multiple myeloma, IgG lambda type Durie-Salmon Stage II, was admitted because of gradually developing anemia and increased blasts with abnormal karyotype in her bone marrow after 10 years of treatment. The chromosomal analysis showed 44, XX, del(5q), del(7q), -9, add(12p), -21, typical of secondary MDS due to the cumulative alkylating agents. Thrombocytosis concomitantly occurred with emergence of chromosomal abnormality, but the serum interleukin 6 level was not elevated, which suggested that it was related to development of secondary MDS.

Mutations causing high basal level transcription that is independent of transcriptional activators but dependent on chromosomal position in Saccharomyces cerevisiae

Two single (bel2 and bel4) and two double (bel3 bel7 and bel5 be16) mutations causing enhanced transcription of a gene fusion, consisting of the open reading frame of PHO5 connected to the HIS5 promoter (HIS5p) integrated at the ura3 or leu2 locus, were isolated from a gcn4-disrupted mutant of Saccharomyces cerevisiae. The PHO5 gene, encoding repressible acid phosphatase, in the HIS5p-PHO5 construct was derepressed under amino acid starved conditions by the action of the transcriptional activator Gcn4p. The bel mutants showed temperature-sensitive cell growth and/or cell aggregation. All the mutants except bel4 also showed high levels of transcription of an intact PHO5 DNA integrated at the URA3 locus in the absence of the cognate transcriptional activator, Pho4p, and in the absence of upstream activating sequences of PHO5. The HIS5 and PHO5 genes at their original chromosomal positions were, however, not affected by the bel2 mutation. The BEL2 gene was found to be identical with SIN4/TSF3, mutations in which cause high levels of transcription of the HO and GAL genes in the absence of their respective transcriptional activators, Swi5p and Gal4p. The effect of the bel2/sin4/tsf3 mutation on PHO5 transcription was additive with the Pho4p function. Thus the effect of the bel2/sin4/tsf3 mutation is dependent on the position of PHO5 in the chromosome and independent of Pho4p and Gen4p activation.

[Targeted toxin therapy in the treatment of leukemia]

A chimeric toxin in which the cell surface binding domain of Pseudomonas exotoxin was replaced with mature human granulocyte colony-stimulating factor (G-CSF) was produced in Escherichia coli, partially purified and tested for its biological activity on a G-CSF-dependent murine myeloid leukemia cell line, NFS60. This fusion protein, termed as G-CSF-PE40, can displace [125I] G-CSF binding to its receptor. After 48 hrs incubation in the presence of G-CSF, G-CSF-PE40 inhibited protein synthesis and revealed cytotoxicity in NFS60 cells in a concentration dependent manner. The half maximal dose of G-CSF-PE40 for protein synthesis inhibition (ID50) in NFS60 cells was estimated at around 100pM. Additionally, relatively low concentration of G-CSF-PE40 stimulated DNA synthesis in NFS60 cells after 16 hrs' incubation in the absence of G-CSF, suggesting that G-CSF-PE40 also can transduce a transient mitogenic signal. Thus, G-CSF-PE40 may be useful in the selective elimination of myeloid cells expressing G-CSF receptors, especially in combination with chemotherapeutic agents like cytosine arabinoside.

Determination of a new fluoroquinolone antimicrobial agent, (S)-10-[(S)-(8-amino-6-azaspiro d3,4]octan-6-yl)]-9-fluoro-2, 3-dihydro-3-methyl-7-oxo-7H-pyrido[1,2,3-de][1,4]benzoxazine-6- carboxylic acid hemihydrate, DV-7751a, in human serum and urine using solid-phase extraction and high-performance liquid chromatography with fluorescence detection

A high-performance liquid chromatographic method for the determination of a new fluoroquinolone antimicrobial agent, (S)-10-[(S)-(8-amino-6-azaspiro[3,4]octan-6-yl)]-9-fluoro-2,3- dihydro-3-methyl-7-oxo-7H-pyrido[1,2,3-de][1,4]benzoxazine-6-carboxylic acid hemihydrate (DV-7751a, I) in human serum and urine has been developed. Compound I and the internal standard were extracted from serum and urine by means of Bond Elut C8 LRC column. The extracts were chromatographed on a reversed-phase Inertsil ODS-2 column using tetrahydrofuran-50 mM KH2PO4 (pH2)-1 M ammonium acetate (19:81:1, v/v) as the mobile phase at a flow-rate of 1.0 ml/min. Fluorescence detection at an excitation wavelength of 305 nm and an emission wavelength of 530 nm resulted in a limit of quantitation of 0.0098 microgram/ml for serum and 0.098 microgram/ml for urine. The method showed satisfactory sensitivity, precision, accuracy, recovery and selectivity. Stability studies showed that I was stable in serum and urine for at least 1 month at -20 degrees C and for at least 48 h at room temperature.

Selective induction of interleukin-4- and interferon-y-producing T cells from cord blood naive T cells. Effects of costimulatory signaling through CD28

We investigated the effect of costimulation through CD28 and CD11a on the differentiation of human naive CD4+ T cells with restricted cytokine production profiles. Interleukin (IL)-4 and interferon-gamma (IFN-gamma) were measured by ELISA and IL-2 was detected by a bioassay. Naive CD4+ T cells proliferated and produced IL-2 upon cross-linking of CD3, and costimulation through CD28 enhanced IL-2 production. After repeated stimulation, CD4+ T cells which were stimulated in the absence of costimulation through CD28 lost their ability to secrete IL-2 and started secreting IL-4 and IFN-gamma. Instead in the presence of costimulation through CD28, they secreted IL-2, IL-4 and IFN-gamma. Blocking of endogenous IL-4 activity with anti-IL-4 Ab suppressed the IL-4 secretion and proliferation of T cells.

Functional domains of Pho81p, an inhibitor of Pho85p protein kinase, in the transduction pathway of Pi signals in Saccharomyces cerevisiae

The PHO81 gene is thought to encode an inhibitor of the negative regulators (Pho80p and Pho85p) in the phosphatase (PHO) regulon. Transcription of PHO81 is regulated by Pi signals through the same PHO regulatory system. Elimination of the PHO81 promoter or its substitution by the GAL1 promoter revealed that stimulation of the PHO regulatory system requires both increased transcription of PHO81 and a Pi starvation signal. The predicted Pho81p protein contains 1,179 amino acids (aa) and has six repeats of an ankyrin-like sequence in its central region. The minimum amino acid sequence required for Pho81p function was narrowed down to a 141-aa segment (aa 584 to 724), which contains the fifth and sixth repeats of the ankyrin-like motif. The third to sixth repeats of the ankyrin-like motif of Pho81p have significant similarities to that of p16INK4, which inhibits activity of the human cyclin D-CDK4 kinase complex. Deletion analyses revealed that the N- and C-terminal regions of Pho81p behave as negative and positive regulatory domains, respectively, for the minimal 141-aa region. The negative regulatory activity of the N-terminal domain was antagonized by a C-terminal segment of Pho81p supplied in trans. All four known classes of PHO81c mutations that show repressible acid phosphatase activity in high-Pi medium affect the N-terminal half of Pho81p. An in vitro assay showed that a glutathione S-transferase-Pho81p fusion protein inhibits the Pho85p protein kinase. Association of Pho81p with Pho85p or with the Pho80p-Pho85p complex was demonstrated by the two-hybrid system.

Powerful hepatoprotective and hepatotoxic plant oligostilbenes, isolated from the Oriental medicinal plant Vitis coignetiae (Vitaceae)

The methanol extract of the Oriental medicinal plant Vitis coignetiae (Vitaceae) showed hepatoprotective activity in the in vitro assay method using primary cultured rat hepatocytes. Activity-guided fractionation of the extract afforded epsilon-viniferin as an active principle. The protective effect of epsilon-viniferin against mice carbon tetrachloride-induced hepatic injury in mice was shown by serum enzyme assay as well as by pathological examination. In addition to epsilon-viniferin, plant oligostilbenes, ampelopsins A, C, F and the mixture of vitisin A and cis-vitisin A were also present in the extract. Among them, ampelopsin C and the mixture of vitisin A and cis-vitisin A were found to be powerful hepatotoxins.

Antidepressant principles of Valeriana fauriei roots

A methanol extract of the roots of Valeriana fauriei (Valerianaceae), exhibited antidepressant activity in mice. The extract was fractioned, monitored by the activity, to afford alpha-kessyl alcohol as an active principle. The antidepressant activity of some guaiane and valerane types of sesquiterpenoids in the active fraction was also evaluated.

Takayasu's disease associated with ulcerative colitis

A 14-year-old female with ulcerative colitis developed right anterior cervical pain and high fever. Cervical contrast-enhanced computed tomography (CE-CT) showed a wall thickness of the right common carotid artery which suggested aortitis. Her pulmonary angiography demonstrated a narrowing of the pulmonary arteries and she was diagnosed as having Takayasu's disease associated with ulcerative colitis. HLA analysis showed Bw52 and DR2 haplotype, which is frequently found in patients with Takayasu's disease associated with ulcerative colitis.

Binding properties of the components of branched-chain 2-oxo acid dehydrogenase complex on ELISA

Binding characteristics among three catalytic components of rat liver branched-chain 2-oxo acid dehydrogenase complex (BCKADH) were investigated by ELISA. Dihydrolipoamide dehydrogenase (E3) was bound to solid-phase dihydrolipoamide acyltransferase (E2). The binding curve was hyperbolic giving a calculated half-maximal binding concentration of 167 ng/ml for E3. Specificity of the binding of E3 to E2 was certified by a competition experiment measuring binding of biotin-labeled E3 in the presence of unlabeled E3. The decarboxylase component (E1), which is the other catalytic component of the complex, prevented the E3 binding to E2. The specific binding between E2 and E3 was verified in the opposite direction with immobilized E3. E2 also bound to solid-phase E1 in a specific manner, and addition of E3 prevented the E2 binding to E1. No binding between E1 and E3 was observed. Thus, E1 and E3 prevented each other's binding to E2, suggesting that E1 and E3 may recognize overlapped binding sites on the E2 polypeptide or that they may, at least in part, sterically interact with each other on their binding to E2. The reconstitution experiment of the complex also supported such a mutually exclusive binding of E1 and E3 to the E2 core.

[Three cases of respiratory failure of collagen diseases accompanied by syndrome of inappropriate secretion of antidiuretic hormone (SIADH)]

We experienced three patients who have collagen diseases with respiratory failure accompanied by hyponatremia. They were one systemic lupus erythematosus patient with interstitial pneumonia, one rheumatoid arthritis patient with acute pneumonitis, and one dermatomyositis patient with pulmonary fibrosis and organizing pneumonia. In all 3 patients, hyponatremia appeared along with a decrease in arterial O2 partial pressure (PaO2) and the hyponatremia tended to improve when the PaO2 increased after inhalation of oxygen, even though their respiratory failure were not improved. In dermatomyositis patient, serum Na levels were over-corrected after increase in PaO2. The serum and urine osmolality, serum antidiuretic hormone (ADH) levels and clinical pictures demonstrated a presence of inappropriate secretion of ADH (SIADH) in all 3 cases when hyponatremia and hypoxia appeared. A close association between hyponatremia and hypoxia observed in 3 patients strongly suggested that their SIADH were associated with hypoxia since SIADH could be demonstrated by hypoxia. Therefore, it is important to realize that hypoxia-induced hyponatremia will be promptly corrected to hypernatremia by an oxygen inhalation, which could cause a lethal central pontine myelinolysis.

Ca2+ release induced by myotoxin alpha, a radio-labellable probe having novel Ca2+ release properties in sarcoplasmic reticulum

1. Myotoxin alpha (MYTX), a polypeptide toxin purified from the venom of prairie rattlesnakes (Crotalus viridis viridis) induced Ca2+ release from the heavy fraction (HSR) but not the light fraction of skeletal sarcoplasmic reticulum at concentrations higher than 1 microM, followed by spontaneous Ca2+ reuptake by measuring extravesicular Ca2+ concentrations using the Ca2+ electrode. 2. The rate of 45Ca2+ release from HSR vesicles was markedly accelerated by MYTX in a concentration-dependent manner in the range of concentrations between 30 nM and 10 microM, indicating the most potent Ca2+ releaser in HSR. 3. The Ca2+ dependency of MYTX-induced 45Ca2+ release has a bell-shaped profile but it was quite different from that of caffeine, an inducer of Ca(2+)-induced Ca2+ release. 4. 45Ca2+ release induced by MYTX was remarkable in the range of pCa between 8 and 3, whereas that by caffeine was prominent in the range of pCa, i.e., between 7 and 5.5. 5. MYTX-induced 45Ca2+ release consists of both early and late components. The early component caused by MYTX at low concentrations (30-300 nM) completed within 20 s, while the late component induced by it at higher concentrations (> 0.3 microM) was maintained for at least 1 min. 6. Both the components were almost completely inhibited by inhibitors of Ca2+ such as Mg2+, ruthenium red and spermine. 7. 45Ca2+ release induced by caffeine or beta,gamma-methyleneadenosine 5'-triphosphate (AMP-PCP) was completely inhibited by high concentrations of procaine. Procaine abolished the early component but not the late one, suggesting that at least the early component is mediated through Ca(2+)-induced Ca2+ release channels. 8. On the basis of these results, the character of Ca2+ release induced by MYTX was quite different from that caused by caffeine or AMP-PCP, suggesting that MYTX induces Ca2+ release having novel properties in HSR. MYTX is the first polypeptide Ca2+ inducer and has become a useful pharmacological tool for clarifying the mechanism of Ca2+ release from skeletal muscle SR.

Simple monitoring system for R-mediated site-specific recombination on chromosomes in Saccharomyces cerevisiae

A simple measuring system for the frequency of recombinant clones generated by R-protein mediated recombination was constructed. By applying the system, the frequencies of recombinant clones due to site-specific recombination between two loci on one or two different nonhomologous chromosome(s) were monitored during cultivation. Subsequently, it was found that the frequencies increase nearly in proportion to the culture period and are different among the individual two selected loci. Thus, the system is thought to be a candidate for analyzing physicochemical situations, such as folding and localization, of chromosomes in the nucleus.

Protective effect of heparin on renal glomerular anionic sites of streptozotocin-injected rats

Albuminuria at the rate of 500 micrograms/24 h was observed in rats treated with 50 mg/kg body wt. i.v. streptozotocin (STZ). When STZ was combined with heparin, administered twice daily (250 IU/kg subcutaneous injection) after 24 h following STZ injection, the daily urinary albumin excretion (U-AE) was less than half the amount found in non-heparinized rats (280.3 micrograms/24 h). The observation period in both instances was 8 weeks. When animals were permitted to develop albuminuria over the first 4 weeks, subsequent heparin administration for another 4 weeks lowered U-AE from 500 micrograms/24 h to less than half the amount (227.8 micrograms/24 h). A significantly negative correlation (P < 0.001) existed between U-AE and the number of anionic sites (AS) in the lamina rara externa of glomerular basement membranes, as visualized by electron microscopy. The number of AS per 1000 nm in STZ-injected rats (15.5 +/- 0.2) was lower than that in control rats (23.1 +/- 0.6); however, in heparinized animals, regardless of STZ, the values were not significantly different from normal. Heparin by itself had no effect on the number of AS in normal rats. All STZ-injected animals became hyperglycemic (400-550 mg/dl), but received no insulin. Heparin had no effect on plasma glucose levels. From these results, it is concluded that heparin suppressed both of an increase in U-AE and a decrease in AS count of glomerular basement membranes in STZ-injected rats.

[Polyarteritis nodosa]

The following points on polyarteritis nodosa (PN) were presented: definition, difference between PN and vascular lesions in other collagen disease, diagnostic criteria, clinical symptoms and laboratory findings, clinical type, histologic stage, therapy and three case reports with two active vasculitis and one scarred vasculitis.

[Severe ascending aortic stenosis after one-stage repair of aortopulmonary window and interrupted aortic arch]

A 33-day-old girl was transferred to our hospital because of severe cyanosis and tachypnea. The diagnosis of aortopulmonary window and interrupted aortic arch was established by echocardiogram and cineangiocardiogram. Reconstruction of aortic arch by extended direct anastomosis and simple patch closure of aortopulmonary window were performed by means of profound hypothermia and circulatory arrest on 36 days of age. Her postoperative clinical course was uneventful, but at 2 months after operation, stenosis of the ascending aorta was noticed by echocardiographic examination. As her physical growth had been satisfactory, she was managed under close observation at outpatient clinic. At seven months after operations, she fell into progressive left heart failure, and emergency operation was carried out for the relief of stenosis of the ascending aorta, but she could not come off bypass. A stenosis of the ascending aorta is a fatal complication that may occur after one-stage repair of interrupted aortic arch with aortopulmonary window consisting of extended direct anastomosis and simple patch closure. We now consider that division of ascending aorta and pulmonary artery and repair of both of the defect is indispensable for the correction of aortopulmonary window, especially in neonate and small infant with this lesion associated with interrupted aortic arch.

Occurrence of genetic segregation in a putative haploid strain of Endomyces fibuliger met by spontaneous sectoring of protoplast fusants

Detailed genetic analysis of Endomyces fibuliger, an amylolytic yeast which is homothallic and exists predominantly in the diploid state, has not been performed. From a naturally occurring strain, E. fibuliger 8014 met, a morphological mutant, 193 met, was obtained by u.v. mutagenesis. To obtain a haploid strain suitable for genetic analysis, an intergeneric hybrid between E. fibuliger 193 met and a strain of a closely related dimorphic heterothallic lipolytic yeast, Yarrowia lipolytica, A his1, was produced by mass mating. The intergeneric hybrid was highly unstable in vegetative culture on yeast extract/phosphate/soluble starch/agar media and produced numerous mitotic sectors. Most of the sectors were mitotically unstable. However, one mitotically stable sector, N14i60 met, was obtained which also differed from the strain 193 as gauged by the appearance of DNA bands on pulsed-field gel electrophoresis. The putative haploid strain, N14i60 met, had six bands whilst the mutant 193 met had seven. Ultra-violet treatment of cells of N14i60 met produced 19 auxotrophic mutants. Protoplast fusion between pairs of different mutants showed complementation and the fusants were unstable mitotically and gave unstable aneuploid and stable haploid sectors of parental and non-parental combinations of markers. It is postulated that complementary diploid fusants, which were obtained by protoplast fusion, produced sectors by mitotic non-disjunction. Such a mechanism provides a means to establish a genetic analysis system for E. fibuliger via the parasexual cycle.