scholarly journals An unusual complementation in non-excitable mutants in Paramecium

2000 ◽  
Vol 76 (2) ◽  
pp. 125-133 ◽  
Author(s):  
ATSUSHI MATSUDA ◽  
YOSHIRO SAIMI ◽  
MIHOKO TAKAHASHI
Keyword(s):  
Genetic Relationship ◽  
The Other ◽  
Unusual Feature ◽  
Marker Genes ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Other Hand ◽  
Wild Type Phenotype ◽  
Allelic Interaction

A non-excitable behavioural mutant, d4-662, was previously characterized as the fourth pawn locus mutant pwD in Paramecium tetraurelia. We now provide data demonstrating that d4-662 is in fact controlled by a pwB allele that has the unusual feature of complementing other pwB alleles in heterozygous F1 progeny. Neither the cytoplasm nor the nucleoplasm of d4-662 cured the mutational defects of pwB and in the reverse combination of d4-662 and pwB, the result was the same. On the other hand, pwA, another non-excitable mutant, was cured upon cross-injection with d4-662 and mutants carrying trichocyst non-discharge marker genes were also cured. This evidence suggests that d4-662 is a new mutant belonging to pwB, and would be better designated as pwB662. Extensive crossbreeding analyses, however, showed an unusual genetic relationship between d4-662 and pwB (pwB95 or pwB96). When d4-662 was crossed with pwB mutants, many progeny expressing wild-type phenotype or mixed clones of wild-type and pawn cells were obtained in the F1. Less than 12·5% expressed the pawn phenotype. The appearance of wild-type progeny in this F1 strongly suggests that an inter-allelic interaction between pwB662 and other pwB alleles may occur during development of the macronucleus.

Nutritional Requirement for 4-Aminobenzoate Caused by Mutation of Dihydropteroate Synthetase

1976 ◽  
Vol 31 (5-6) ◽  
pp. 285-287 ◽  
Author(s):  
Helmut Rappold ◽  
Adelbert Bacher
Keyword(s):  
Parent Strain ◽  
The Other ◽  
Synthetase Activity ◽  
Nutritional Requirement ◽  
Wild Type ◽  
Aerobacter Aerogenes ◽  
Low Level ◽  
Other Hand ◽  
High Concentrations

Abstract Aerobacter aerogenes mutant 62-1 AC requires high concentrations of 4-aminobenzoate for growth. The mutant accumulates N-glucosyl-4-aminobenzoate and has an intact 4-aminobenzoate synthetase (Bacher, Gilch, Rappold, and Lingens, Z. Naturforsch. 28c, 614 - 617 [1973]). On the other hand the ability of the mutant to synthesize dihydropteroate is markedly reduced. The dihydropteroate synthetase level of mutant 62-1 AC is 1% as compared to the parent strain. Spontaneous revertants of mutant 62-1 AC show wild type levels of dihydropteroate synthetase. We conclude that the requirement for 4-aminobenzoate in mutant 62-1 AC is due to poor utilization of 4-aminobenzoate as a consequence of the low level of dihydropteroate synthetase activity.

H-Ras Is Involved in the Inside-out Signaling Pathway of Interleukin-3–Induced Integrin Activation

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1540-1548 ◽  
Author(s):  
Hirohiko Shibayama ◽  
Naoyuki Anzai ◽  
Stephen E. Braun ◽  
Seiji Fukuda ◽  
Charlie Mantel ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Dominant Negative ◽  
The Other ◽  
Wild Type ◽  
Integrin Activation ◽  
Mapk Kinase ◽  
Interleukin 3 ◽  
Other Hand ◽  
Inside Out ◽  
Constitutively Active

Abstract The proto-oncogene product, p21ras, has been implicated in the cellular mechanism of adhesion, although its precise role has been controversial. Numerous cytokines and growth-factors activate Ras, which is an important component of their growth-promoting signaling pathways. On the other hand, the role of Ras in cytokine-induced adhesion has not been elucidated. We therefore investigated the function of H-Ras in the inside-out signaling pathway of interleukin-3 (IL-3)–induced integrin activation in the murine Baf3 cell line after transfection of cells with either constitutively active, dominant-negative, or wild-type H-Ras cDNAs. Adhesion of Baf3 cells to fibronectin was induced by IL-3 in a dose-dependent manner via very late antigen-4 (VLA-4; 4β1 integrins) and VLA-5 (5β1 integrins) activation. On the other hand, IL-4 did not induce the adhesion of Baf3 cells to fibronectin, although IL-4 did stimulate the cell proliferation of Baf3 cells. Constitutively active H-Ras–transfected Baf3 cells adhered to fibronectin without IL-3 stimulation through VLA-4 and VLA-5, whereas dominant-negative H-Ras–transfected Baf3 cells showed significantly less adhesion induced by IL-3 compared with wild-type and constitutively active H-Ras–transfected Baf3 cells. Anti-β1 integrin antibody (clone; 9EG7), which is known to change integrin conformation and activate integrins, induced the adhesion of dominant-negative H-Ras–transfected Baf3 cells as much as the other types of H-Ras–transfected Baf3 cells. 8-Br-cAMP, Dibutyryl-cAMP, Ras-Raf-1 pathway inhibitors, and PD98059, a MAPK kinase inhibitor, suppressed proliferation and phosphorylation of MAPK detected by Western blotting with anti–phospho-MAPK antibody, but not adhesion of any type of H-Ras–transfected Baf3 cells, whereas U-73122, a phospholipase C (PLC) inhibitor, suppressed adhesion of these cells completely. These data indicate that H-Ras and PLC, but not Raf-1, MAPK kinase, or the MAPK pathway, are involved in the inside-out signaling pathway of IL-3–induced VLA-4 and VLA-5 activation in Baf3 cells.

scholarly journals Effects of Maternal Levels of Thyroid Hormone (TH) on the Hypothalamus-Pituitary-Thyroid Set Point: Studies in TH Receptor β Knockout Mice

Endocrinology ◽  
2007 ◽  
Vol 148 (11) ◽  
pp. 5305-5312 ◽  
Author(s):  
Manuela Alonso ◽  
Charles Goodwin ◽  
XiaoHui Liao ◽  
David Page ◽  
Samuel Refetoff ◽  
...  
Keyword(s):  
Thyroid Hormone ◽  
Elevated Serum ◽  
The Other ◽  
Long Term Effects ◽  
Intrauterine Environment ◽  
Set Point ◽  
Other Hand ◽  
Wild Type Phenotype ◽  
Pituitary Thyroid Axis ◽  
Serum Tsh

A level of thyroid hormone (TH) in agreement with the tissue requirements is essential for vertebrate embryogenesis and fetal maturation. In this study we evaluate the immediate and long-term effects of incongruent intrauterine TH levels between mother and fetus using the TH receptor (TR) β−/− knockout mouse as a model. We took advantage of the fact that the TRβ−/− females have elevated serum TH but are not thyrotoxic due to resistance to TH. We used crosses between heterozygotes with wild-type phenotype (TRβ+/−) males and TRβ−/− females, with a hyperiodothyroninemic (high T4 and T3 levels) intrauterine environment (TH congruent with the TRβ−/− fetus and excessive for the TRβ+/− fetus), and reciprocal crosses between TRβ−/− males and TRβ+/− females, providing a euiodothyroninemic intrauterine environment. We found that TRβ−/− dams had reduced litter sizes and pups with lower birth weight but preserved the mendelian TRβ−/− to TRβ+/− ratio at birth, indicating that the incongruous TH levels did not decrease intrauterine survival of a specific genotype. The results of studies in newborns demonstrate that TRβ+/− pups born to TRβ−/− dams have persistent suppression of serum TSH without a peak. On the other hand, TRβ−/− pups born to TRβ+/− dams have lower serum TSH at birth and a tendency to peak higher, compared with TRβ−/− pups born to TRβ−/− dams. The studies in the adult progeny demonstrate that TRβ+/− mice born to TRβ−/− dams and, thus, exposed to higher intrauterine TH levels, have greater resistance to TH at the level of the pituitary when stimulated with TRH. On the other hand, TRβ−/− mice born to TRβ+/− dams and, thus, deprived of TH in uterine life, were more sensitive to TH when similarly stimulated with TRH. Thus, TH exposure in utero has an effect on the regulatory set point of the hypothalamus-pituitary-thyroid axis, which can be seen early in life and persists into adulthood.

scholarly journals The UDP-Glc:Glycoprotein Glucosyltransferase Is Essential for Schizosaccharomyces pombe Viability under Conditions of Extreme Endoplasmic Reticulum Stress

1998 ◽  
Vol 143 (3) ◽  
pp. 625-635 ◽  
Author(s):  
Sandra Fanchiotti ◽  
Fabiana Fernández ◽  
Cecilia D'Alessio ◽  
Armando J. Parodi
Keyword(s):  
Cell Viability ◽  
Schizosaccharomyces Pombe ◽  
Double Mutant ◽  
Expression Vector ◽  
The Other ◽  
Wild Type ◽  
Glucosidase Ii ◽  
Wild Type Phenotype ◽  
Polypeptide Chains ◽  
Mutant Cells

Interaction of monoglucosylated oligosaccharides with ER lectins (calnexin and/or calreticulin) facilitates glycoprotein folding but this interaction is not essential for cell viability under normal conditions. We obtained two distinct single Schizosaccharomyces pombe mutants deficient in either one of the two pathways leading to the formation of monoglucosylated oligosaccharides. The alg6 mutant does not glucosy- late lipid-linked oligosaccharides and transfers Man9GlcNAc2 to nascent polypeptide chains and the gpt1 mutant lacks UDP-Glc:glycoprotein glucosyltransferase (GT). Both single mutants grew normally at 28°C. On the other hand, gpt1/alg6 double-mutant cells grew very slowly and with a rounded morphology at 28°C and did not grow at 37°C. The wild-type phenotype was restored by transfection of the double mutant with a GT-encoding expression vector or by addition of 1 M sorbitol to the medium, indicating that the double mutant is affected in cell wall formation. It is suggested that facilitation of glycoprotein folding mediated by the interaction of monoglucosylated oligosaccharides with calnexin is essential for cell viability under conditions of extreme ER stress such as underglycosylation of proteins caused by the alg6 mutation and high temperature. In contrast, gls2/alg6 double-mutant cells that transfer Man9GlcNAc2 and that are unable to remove the glucose units added by GT as they lack glucosidase II (GII), grew at 37°C and had, when grown at 28°C, a phenotype of growth and morphology almost identical to that of wild-type cells. These results indicate that facilitation of glycoprotein folding mediated by the interaction of calnexin and monoglucosylated oligosaccharides does not necessarily require cycles of reglucosylation–deglucosylation catalyzed by GT and GII.

scholarly journals The biosynthesis of serine and glycine in Pseudomonas AM1 with special reference to growth on carbon sources other than C1 compounds

1971 ◽  
Vol 121 (5) ◽  
pp. 753-762 ◽  
Author(s):  
W. Harder ◽  
J. R. Quayle
Keyword(s):  
Essential Role ◽  
Carbon Sources ◽  
Enzymic Activity ◽  
Serine Hydroxymethyltransferase ◽  
The Other ◽  
Wild Type ◽  
Phosphoserine Phosphatase ◽  
Wild Type Phenotype ◽  
Phosphoglycerate Dehydrogenase ◽  
Serine Biosynthesis

1. A mutant, 20S, of Pseudomonas AM1 was obtained that requires a supplement of serine to grow on succinate, lactate or ethanol. This mutant lacks phosphoserine phosphatase and revertants to wild-type phenotype regained this enzymic activity showing that the phosphorylated pathway of serine biosynthesis is necessary for growth on these three substrates. 2. The requirement for supplemental serine by mutant 20S could be met by glycine, suggesting that Pseudomonas AM1 can obtain C1 units from glycine. 3. Mutant 20S grows on C1 compounds at a lower rate compared with the wild type. Supplementation with serine stimulated the growth rate of the mutant suggesting that the phosphorylated pathway of serine biosynthesis plays some role, but not an essential role, during growth on C1 compounds. 4. A mutant, 82G, was obtained that requires a supplement of glycine to grow on succinate, lactate or ethanol. When grown in such supplemented media, the mutant lacks serine hydroxymethyltransferase and revertants to wild-type phenotype regained enzymic activity showing that during growth on succinate, lactate or ethanol, glycine is made from serine via serine hydroxymethyltransferase, and that the organism can obtain C1 units from glycine. 5. Mutant 82G grew on methanol and then contained serine hydroxymethyltransferase suggesting that this enzyme is necessary for growth on C1 compounds and that Pseudomonas AM1 may synthesize two such enzymes, one used in growth on C1 compounds, the other used in growth on other substrates. Mutant 82G might lack the latter enzyme. 6. Phosphoglycerate dehydrogenase is specifically inhibited by l-serine and the regulatory implications of this are discussed.

MUTANTS WITH ALTERED Ca2+-CHANNEL PROPERTIES IN PARAMECIUM TETRAURELIA: ISOLATION, CHARACTERIZATION AND GENETIC ANALYSIS

Genetics ◽  
1984 ◽  
Vol 108 (3) ◽  
pp. 545-558
Author(s):  
Robert D Hinrichsen ◽  
Yoshiro Saimi ◽  
Ching Kung
Keyword(s):  
Genetic Analysis ◽  
Complementation Group ◽  
Phenotypic Change ◽  
Paramecium Tetraurelia ◽  
Wild Type ◽  
Cytoplasmic Factor ◽  
Wild Type Phenotype ◽  
Channel Properties ◽  
Ca2 Channels ◽  
F1 Generation

ABSTRACT Dancers are a group of mutants in Paramecium tetraurelia whose Ca2+ current inactivates poorly and are likely to be defective in the structure of their Ca2+ channels. These mutants show prolonged backward swimming in response to K+ and Ba2+ in the medium and were selected by this property in a galvanotactic trough. The dancer mutants are semidominant, and all isolated mutants belong to one complementation group; they are not allelic to any of the previously isolated behavioral mutants of P. tetraurelia. The phenotypic change from the homozygous parent to heterozygous F1 generation takes three to five fissions. There is no evidence of a cytoplasmic factor capable of converting the dancer to the wild-type phenotype, as has been demonstrated in the mutants pawn and cnr. We suggest that the dancer locus is a structural gene for the Ca2+ channel.

Abstract 16603: Appropriate Timing of Pacemaker Implantation in Patients With Wild-Type and Variant Amyloidogenic Transthyretin Cardiac Amyloidosis

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Yusei Kawahara ◽  
Miwa Ito ◽  
Tadashi Hoshiyama ◽  
Hisanori Kanazawa ◽  
Kenichi Tsujita
Keyword(s):  
Cardiac Amyloidosis ◽  
Pacemaker Implantation ◽  
The Other ◽  
Cardiac Conduction ◽  
Wild Type ◽  
Conduction Disorders ◽  
Other Hand ◽  
Conduction Disorder ◽  
Second Degree

Background and Objectives: It has been shown that cardiac conduction disorders can be seen in patients with wild-type amyloidogenic transthyretin (ATTRwt) and variant ATTR (ATTRv) cardiac amyloidosis. However, its appropriate timing of pacemaker implantation has not been clarified yet. Methods and Results: The consecutive 100 patients with ATTRwt cardiac amyloidosis who diagnosed by myocardium biopsy and/or technetium-99m-pyrophosphate scintigraphy and 62 patients with ATTRv cardiac amyloidosis who diagnosed by means of genetic screening were included in this study. In patients with ATTRwt cardiac amyloidosis, 21 patients have normal conduction at the time of diagnosis. However, conduction disorder had seen in only 5 patient (first degree atrioventricular block (AVB); 4 patients, complete AVB; 1 patients) and only one patient underwent cardiac implantable electric device (CIED) implantation during follow-up period. On the other hand, in patients with ATTRv cardiac amyloidosis, 36 patients have normal conduction at the time of diagnosis. However, conduction disorder had seen in 13 patient (first degree AVB; 8 patients, second degree AVB; 3 patients, trifascicular block; 1 patients, complete AVB; 1 patients) (5/21 vs 13/36, p=0.335) and 6 patients underwent CIED implantation during follow-up period (1/21 vs 6/36, p=0.186). Furthermore, in ATTRwt cardiac amyloidosis, 10 patients (first degree AVB; 2 patients, second degree AVB; 1 patient, trifascicular block; 7 patients) had underwent CIED implantation because of cardiac conduction disorders and/or prevention of sudden cardiac death. However, only 4 patients with trifascicular block progressed to complete AVB.On the other hand, In ATTRv cardiac amyloidosis, 14 patients (first degree AVB; 2 patients, second degree AVB; 4 patient, trifascicular block; 8 patients) had underwent CIED implantation for same reason. However, only 3 patients with trifascicular block progressed to complete AVB. Conclusions: Patients with ATTRv cardiac amyloidosis were more likely to progress conduction disorders than those with ATTRwt cardiac amyloidosis. However, prophylactic pacemaker implantation might had not need in both ATTRwt and ATTRv patients with first or second degree AVB.

scholarly journals Suppression of Viral Replication by Stress-Inducible GADD34 Protein via the Mammalian Serine/Threonine Protein Kinase mTOR Pathway

2007 ◽  
Vol 81 (20) ◽  
pp. 11106-11115 ◽  
Author(s):  
Kahori Minami ◽  
Yukihiro Tambe ◽  
Ryosuke Watanabe ◽  
Takahiro Isono ◽  
Masataka Haneda ◽  
...  
Keyword(s):  
Viral Replication ◽  
Critical Role ◽  
Cellular Protein ◽  
Mtor Pathway ◽  
The Other ◽  
Mtor Signaling Pathway ◽  
Wild Type ◽  
Other Hand ◽  
Vesicular Stomatitis ◽  
Pathway Inhibition

ABSTRACT GADD34 is a protein that is induced by a variety of stressors, including DNA damage, heat shock, nutrient deprivation, energy depletion, and endoplasmic reticulum stress. Here, we demonstrated that GADD34 induced by vesicular stomatitis virus (VSV) infection suppressed viral replication in wild-type (WT) mouse embryo fibroblasts (MEFs), whereas replication was enhanced in GADD34-deficient (GADD34-KO) MEFs. Enhanced viral replication in GADD34-KO MEFs was reduced by retroviral gene rescue of GADD34. The level of VSV protein expression in GADD34-KO MEFs was significantly higher than that in WT MEFs. Neither phosphorylation of eIF2α nor cellular protein synthesis was correlated with viral replication in GADD34-KO MEFs. On the other hand, phosphorylation of S6 and 4EBP1, proteins downstream of mTOR, was suppressed by VSV infection in WT MEFs but not in GADD34-KO MEFs. GADD34 was able to associate with TSC1/2 and dephosphorylate TSC2 at Thr1462. VSV replication was higher in TSC2-null cells than in TSC2-expressing cells, and constitutively active Akt enhanced VSV replication. On the other hand, rapamycin, an mTOR inhibitor, significantly suppressed VSV replication in GADD34-KO MEFs. These findings demonstrate that GADD34 induced by VSV infection suppresses viral replication via mTOR pathway inhibition, indicating that cross talk between stress-inducible GADD34 and the mTOR signaling pathway plays a critical role in antiviral defense.

Mutagenesis-induced conformational change in domain B of a pullulan-hydrolyzing α-amylase TVA I

Amylase ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Takashi Tonozuka ◽  
Takanori Nihira ◽  
Masahiro Mizuno ◽  
Atsushi Nishikawa ◽  
Shigehiro Kamitori
Keyword(s):  
Kinetic Analysis ◽  
Crystal Structures ◽  
Conformational Change ◽  
The Other ◽  
Wild Type ◽  
Other Hand ◽  
Thermoactinomyces Vulgaris ◽  
Catalytic Cleft

Abstract An α-amylase from Thermoactinomyces vulgaris, TVA I, hydrolyzes both α-1,4- and α-1,6-glucosidic linkages. Two variants of TVA I have been previously constructed, one containing a substitution of three residues, Ala357- Gln359-Tyr360, with Val-Asn-Glu (AQY/VNE), and the other bearing a deletion of 11 residues from Ala363 to Asn373 (Del11). The activities of both AQY/VNE and Del11 for the α-1,4-glucosidic linkage of maltotriose were decreased compared to that of wild-type TVA I, while the activities of the two variants for the α-1,6-glucosidic linkage of a trisaccharide, isopanose, were less significantly altered. Here, we determined the crystal structures of AQY/VNE and Del11. The structure of AQY/VNE was almost isomorphous with that of wild-type TVA I. On the other hand, the structure of Del11 showed that a conformational change in domain B was induced by the 11-residue deletion, causing narrowing of the catalytic cleft. Taken together with the results of kinetic analysis, this narrower catalytic cleft is likely responsible for the preference of the TVA I enzyme for the α-1,6-glucosidic linkage.

ULTRAVIOLET LIGHT SENSITIVE MUTANTS OF USTILAGO VIOLACEA

1970 ◽  
Vol 12 (4) ◽  
pp. 891-904 ◽  
Author(s):  
Alan W. Day ◽  
Lynne L. Day
Keyword(s):  
Ultraviolet Light ◽  
Recovery Process ◽  
The Other ◽  
Marker Genes ◽  
Wild Type ◽  
Dark Repair ◽  
Repair Gene ◽  
Ustilago Violacea ◽  
Repair Enzymes

Nine UV-sensitive mutants of U. violacea have been isolated and shown by analysis of complementation and recombination to represent four to five genes. Genes uvs-1 and uvs-3, unlike the other genes and the wild type, are incapable of postirradiation recovery on water agar and are therefore assumed to be deficient in dark repair. Gene uvs-2 does not affect dark repair but may affect photoreactivation. Mutants u7 and u9 which may represent one to two genes are defective in photoreactivation but not in dark repair. The dark recovery process on water agar is inhibited by caffeine.The survival of UV-sensitive mutants during intergenic complementation in a dicaryon was close to that of the wild type. This efficient complementation establishes that the repair enzymes are freely diffusible in the cytoplasm. None of the mutants are linked closely to each other or to the other marker genes used.

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