Sporulation mutants in Cochliobolus carbonum

1973 ◽  
Vol 51 (1) ◽  
pp. 207-209 ◽  
Author(s):  
K. J. Leonard
Keyword(s):  
Ultraviolet Irradiation ◽  
Segregation Ratio ◽  
Wild Type ◽  
Cochliobolus Carbonum ◽  
The Third ◽  
Germ Tubes

Three types of mutants were induced in cultures of Cochliobolus carbonum by ultraviolet irradiation. The mutant C1 abc formed abnormally shaped conidia which proliferated in chains rather than being arranged in a spiral on the conidiophore as in wild-type isolates; a second mutant, C2 pcg, produced conidia which germinated precociously while still attached to the conidiophore and which formed secondary conidia at the ends of short germ tubes; and the third, C1 nc1, formed no conidia. A fourth mutant, C1 nc2, which also failed to form conidia was isolated from a culture grown on a medium containing acriflavin. A 1: 1 segregation ratio was obtained in crosses of C1 abc × wild type, but in crossesC2 pcg × wild type and C1 nc1 × wild type nearly all of the progeny were wild type. The mutants C2 pcg and C1 nc1 failed to form perithecia but could serve as male parents; C1 nc2 was completely infertile. Preliminary attempts to determine whether the pcg and nc mutants were controlled cytoplasmically were inconclusive.

scholarly journals THE EFFECTS OF HETEROZYGOSITY CHANGES ON VIABILITY IN DROSOPHILA MELANOGASTER

Genetics ◽  
1972 ◽  
Vol 70 (4) ◽  
pp. 595-610
Author(s):  
Ray Moree
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Background ◽  
Laboratory Strain ◽  
Theoretical Expectation ◽  
Wild Type ◽  
Small Deviations ◽  
The Third ◽  
The Difference

ABSTRACT The viability effects of chromosomes from an old and from a new laboratory strain of D. melanogaster were studied in eight factorial combinations and at two heterozygosity levels. The combinations were so constructed that heterozygosity level could be varied in the third chromosomes of the carriers of a homozygous lethal marker, in the third chromosomes of their wild-type segregants, and in the genetic backgrounds of both. Excluding the effect of the marker and the exceptional outcomes of two of the combinations, and taking into account both large and small deviations from theoretical expectation, the following summary is given as the simplest consistent explanation of the results: 1) If total heterozygosities of two segregant types tend toward equality their viabilities tend toward equality also, whether background heterozygosity is high or low; if background heterozygosities is higher the tendency toward equality is slightly greater. 2) If total heterozygosity of two segregant types are unequal the less heterozygous type has the lower viability; the difference is more pronounced when background heterozygosity is low, less when it is high. 3) Differences between segregant viabilities are correlated with differences between the total heterozygosities of the two segregants; genetic background is effective to the extent, and only to the extent, that it contributes to the magnitude of this difference. This in turn appears to underlie, at least partly, the expression of a pronounced interchromosomal epistasis. Thus in this study viability is seen to depend upon both the quantity and distribution of heterozygosity, not only among the chromosomes of an individual but among the individuals of a given combination as well.

INHERITANCE OF RADIATION-INDUCED SPINAL CURVATURES IN THE GUPPY LEBISTES RETICULATUS

1969 ◽  
Vol 11 (4) ◽  
pp. 937-947 ◽  
Author(s):  
Johannes Horst Schröder
Keyword(s):  
Germ Cells ◽  
Vertebral Column ◽  
Segregation Ratio ◽  
X Rays ◽  
Wild Type ◽  
Spinal Curvatures ◽  
Recessive Mutations ◽  
Quantitative Characters ◽  
Radiation Induced ◽  
Lebistes Reticulatus

Hereditary changes in the shape of the vertebral column in Lebistes reticulatus appeared after ancestral irradiation of immature germ cells with 500 or 1000 R of X-rays. Although the mutant to wild-type ratios in the F2 generation after outcrossing fitted a digenic and a trigenic segregation ratio, respectively, the quantitative characters in question are assumed to be caused by recessive mutations of polygenes which are highly mutable.

Administration of the Third Dose of Oral Poliomyelitis Vaccine at 6 to 18 Months of Age

PEDIATRICS ◽  
1994 ◽  
Vol 94 (5) ◽  
pp. 774-775 ◽  
Author(s):  
Keyword(s):  
United States ◽  
Health Care Providers ◽  
The United States ◽  
Preschool Age ◽  
Healthy Children ◽  
Care Providers ◽  
Wild Type ◽  
The Third ◽  
Primary Series ◽  
Poliomyelitis Vaccine

This statement describes a modification of the recommended routine schedule for administering trivalent oral poliomyelitis vaccine (OPV). The American Academy of Pediatrics previously has recommended that healthy children receive a three-dose primary series of OPV at 2, 4, and 15 to 18 months of age and a fourth dose at the time of school entry (4 to 6 years of age).1 Available data indicate that the response rates to the third dose of OPV administered at 6 months of age are as good as the rates following administration of this dose at 15 to 18 months of age. Completion of the three-dose primary series at an earlier age will help health care providers induce immunity against poliomyelitis at an early age. Although wild type poliomyelitis has not caused disease in the United States for many years, the virus remains prevalent in many countries. Continued introduction of the virus into the United States by travelers could result in transmission and disease if high levels of immunity are not maintained in preschool age children. For example, wild type poliovirus type 3 was recently introduced into Canada by a religious sect that did not believe in immunization.2 The virus was probably imported from the Netherlands, where a small epidemic of poliomyelitis occurred in members of the same sect in 1992 and 1993.3 SERUM ANTIBODY RESPONSE FOLLOWING OPV ADMINISTRATION After two doses of OPV are administered at 2 and 4 months of age, 89 to 100% of children vaccinated in the United States have evidence of humoral immunity to poliomyelitis types 1 and 3, and 99 to 100% have immunity to type 2 (Table).

Patterning of angiogenesis in the zebrafish embryo

Development ◽  
2002 ◽  
Vol 129 (4) ◽  
pp. 973-982 ◽  
Author(s):  
Sarah Childs ◽  
Jau-Nian Chen ◽  
Deborah M. Garrity ◽  
Mark C. Fishman
Keyword(s):  
Zebrafish Embryo ◽  
Regular Pattern ◽  
Wild Type ◽  
Cell Fates ◽  
Mutagenesis Screen ◽  
The Third ◽  
Shaped Cell ◽  
Vessel Growth ◽  
Lateral Posterior ◽  
Lineage Analysis

Little is known about how vascular patterns are generated in the embryo. The vasculature of the zebrafish trunk has an extremely regular pattern. One intersegmental vessel (ISV) sprouts from the aorta, runs between each pair of somites, and connects to the dorsal longitudinal anastomotic vessel (DLAV). We now define the cellular origins, migratory paths and cell fates that generate these metameric vessels of the trunk. Additionally, by a genetic screen we define one gene, out of bounds (obd), that constrains this angiogenic growth to a specific path. We have performed lineage analysis, using laser activation of a caged dye and mosaic construction to determine the origin of cells that constitute the ISV. Individual angioblasts destined for the ISVs arise from the lateral posterior mesoderm (LPM), and migrate to the dorsal aorta, from where they migrate between somites to their final position in the ISVs and dorsal longitudinal anastomotic vessel (DLAV). Cells of each ISV leave the aorta only between the ventral regions of two adjacent somites, and migrate dorsally to assume one of three ISV cell fates. Most dorsal is a T-shaped cell, based in the DLAV and branching ventrally; the second constitutes a connecting cell; and the third an inverted T-shaped cell, based in the aorta and branching dorsally. The ISV remains between somites during its ventral course, but changes to run mid-somite dorsally. This suggests that the pattern of ISV growth ventrally and dorsally is guided by different cues. We have also performed an ENU mutagenesis screen of 750 mutagenized genomes and identified one mutation, obd that disrupts this pattern. In obd mutant embryos, ISVs sprout precociously at abnormal sites and migrate anomalously in the vicinity of ventral somite. The dorsal extent of the ISV is less perturbed. Precocious sprouting can be inhibited in a VEGF morphant, but the anomalous site of origin of obd ISVs remains. In mosaic embryos, obd somite causes adjacent wild-type endothelial cells to assume the anomalous ISV pattern of obd embryos. Thus, the launching position of the new sprout and its initial trajectory are directed by inhibitory signals from ventral somites. Zebrafish ISVs are a tractable system for defining the origins and fates of vessels, and for dissecting elements that govern patterns of vessel growth.

scholarly journals Determination of the Factor V Leiden Single-Nucleotide Polymorphism in a Commercial Clinical Laboratory by Use of NanoChip Microelectronic Array Technology

2002 ◽  
Vol 48 (9) ◽  
pp. 1406-1411 ◽  
Author(s):  
Jess G Evans ◽  
Cindy Lee-Tataseo
Keyword(s):  
Clinical Laboratory ◽  
Factor V Leiden ◽  
Factor V ◽  
Third Wave ◽  
Wild Type ◽  
Wave Analysis ◽  
Nucleotide Polymorphism ◽  
Single Nucleotide ◽  
The Third ◽  
Array Technology

Abstract Background: Methods for analysis of the single-nucleotide polymorphism (SNP) known as factor V Leiden (FVL) are described. The technique provides rapid, highly accurate detection of the point mutation that encodes for replacement of arginine-506 with glutamine. After formal assay qualification, 758 clinical samples that had previously been analyzed by the InvaderTM Monoplex Assay were tested as research samples in a commercial clinical laboratory. Methods: Primers specific for factor V (FV) were prepared, and PCR was performed. Samples were analyzed using the NanoChip® Molecular Biology Workstation with fluorescently labeled reporters for wild-type and SNP sequences. Results: Of the 635 samples classified by the Third WaveTM assay as FV wild type, 10 were identified as heterozygous FVL by the NanoChip technique. Similarly, of the 114 putative heterozygous samples, 4 were wild type, and of the 9 reported homozygous samples, 6 were homozygous, 2 were heterozygous, and 1 was FV wild type by the NanoChip assay. All 17 results that were discordant with the Third Wave analysis were confirmed by DNA sequencing to be correctly classified by the NanoChip technology. The Nanochip system was 100% accurate in characterizing wild-type, heterozygous, and homozygous samples compared with accuracies of 99.2%, 90.2%, and 100% for the comparable Third Wave analysis. Conclusions: The NanoChip microelectronic chip array technology is an accurate and convenient method for FVL screening of research samples in a clinical laboratory environment.

scholarly journals Interaction of PomB with the Third Transmembrane Segment of PomA in the Na+-Driven Polar Flagellum of Vibrio alginolyticus

2004 ◽  
Vol 186 (16) ◽  
pp. 5281-5291 ◽  
Author(s):  
Toshiharu Yakushi ◽  
Shingo Maki ◽  
Michio Homma
Keyword(s):  
Marine Bacterium ◽  
Vibrio Alginolyticus ◽  
Wild Type ◽  
Transmembrane Segment ◽  
Mutant Proteins ◽  
Transmembrane Segments ◽  
The Third ◽  
Close Proximity ◽  
Flagellar Rotation ◽  
Lines Of Evidence

ABSTRACT The marine bacterium Vibrio alginolyticus has four motor components, PomA, PomB, MotX, and MotY, responsible for its Na+-driven flagellar rotation. PomA and PomB are integral inner membrane proteins having four and one transmembrane segments (TMs), respectively, which are thought to form an ion channel complex. First, site-directed Cys mutagenesis was systematically performed from Asp-24 to Glu-41 of PomB, and the resulting mutant proteins were examined for susceptibility to a sulfhydryl reagent. Secondly, the Cys substitutions at the periplasmic boundaries of the PomB TM (Ser-38) and PomA TMs (Gly-23, Ser-34, Asp-170, and Ala-178) were combined. Cross-linked products were detected for the combination of PomB-S38C and PomA-D170C mutant proteins. The Cys substitutions in the periplasmic boundaries of PomA TM3 (from Met-169 to Asp-171) and the PomB TM (from Leu-37 to Ser-40) were combined to construct a series of double mutants. Most double mutations reduced the motility, whereas each single Cys substitution slightly affected it. Although the motility of the strain carrying PomA-D170C and PomB-S38C was significantly inhibited, it was recovered by reducing reagent. The strain with this combination showed a lower affinity for Na+ than the wild-type combination. PomA-D148C and PomB-P16C, which are located at the cytoplasmic boundaries of PomA TM3 and the PomB TM, also formed the cross-linked product. From these lines of evidence, we infer that TM3 of PomA and the TM of PomB are in close proximity over their entire length and that cooperation between these two TMs is required for coupling of Na+ conduction to flagellar rotation.

scholarly journals At Least Five Major Genes Are Involved in the Avirulence of an Eleusine Isolate of Pyricularia oryzae on Common Wheat

2020 ◽  
Vol 110 (2) ◽  
pp. 465-471 ◽  
Author(s):  
Soichiro Asuke ◽  
Shuko Nishimi ◽  
Yukio Tosa
Keyword(s):  
Molecular Markers ◽  
Common Wheat ◽  
Finger Millet ◽  
Segregation Ratio ◽  
Pyricularia Oryzae ◽  
Complementation Test ◽  
Wheat Cultivars ◽  
Avirulence Genes ◽  
The Third ◽  
Genetic Mechanisms

Pyricularia oryzae is composed of pathotypes that show host specificity at the plant genus level. To elucidate the genetic mechanisms of the incompatibility between the Eleusine pathotype (pathogenic on finger millet) and common wheat, an Eleusine isolate (MZ5-1-6) was crossed with a Triticum isolate (Br48) pathogenic on wheat, and resulting F1 cultures were sprayed onto common wheat cultivars Hope, Norin 4 (N4), and Chinese Spring (CS). On Hope, avirulent and virulent cultures segregated in a 3:1 ratio, suggesting that two avirulence genes are involved. They were tentatively designated as eA1 and eA2. On N4 and CS, the segregation ratio was not significantly deviated from the 7:1, 15:1, or 31:1 ratios, suggesting that three or more genes are involved. A comparative analysis of the segregation patterns suggested that two of these genes were eA1 and eA2. A complementation test indicated that the third gene (tentatively designated as eA3) was the Ao9 type of the PWT3 gene controlling the avirulence of Avena and Lolium isolates on wheat. The fourth gene (tentatively designated as eA4) was detected by backcrossing 200R72, an F1 culture lacking eA1, eA2, and eA3, with Br48. Comparative analyses of phenotypes and the presence and/or absence of molecular markers in the F1 population revealed that some cultures were avirulent on N4/CS in spite of lacking eA1, eA2, eA3, and eA4, indicating the presence of the fifth gene (tentatively designated as eA5). Taken together, we conclude that at least five avirulence genes are involved in the incompatibility between MZ5-1-6 and N4/CS.

scholarly journals Studies in Mice Deficient for the Autoimmune Regulator (Aire) and Transgenic for the Thyrotropin Receptor Reveal a Role for Aire in Tolerance for Thyroid Autoantigens

Endocrinology ◽  
2009 ◽  
Vol 150 (6) ◽  
pp. 2948-2956 ◽  
Author(s):  
Alexander V. Misharin ◽  
Yuji Nagayama ◽  
Holly A. Aliesky ◽  
Basil Rapoport ◽  
Sandra M. McLachlan
Keyword(s):  
Hashimoto’S Thyroiditis ◽  
Hashimoto's Thyroiditis ◽  
Thyroid Peroxidase ◽  
Graves Disease ◽  
Binding Motif ◽  
Wild Type ◽  
Autoimmune Regulator ◽  
The Third ◽  
A Subunit ◽  
Thyroid Autoantigens

The autoimmune regulator (Aire) mediates central tolerance for many autoantigens, and autoimmunity occurs spontaneously in Aire-deficient humans and mice. Using a mouse model of Graves’ disease, we investigated the role of Aire in tolerance to the TSH receptor (TSHR) in Aire-deficient and wild-type mice (hyperthyroid-susceptible BALB/c background). Mice were immunized three times with TSHR A-subunit expressing adenovirus. The lack of Aire did not influence T-cell responses to TSHR protein or TSHR peptides. However, antibody levels were higher in Aire-deficient than wild-type mice after the second (but not the third) immunization. After the third immunization, hyperthyroidism persisted in a higher proportion of Aire-deficient than wild-type mice. Aire-deficient mice were crossed with transgenic strains expressing high or low-intrathyroidal levels of human TSHR A subunits. In the low-expressor transgenics, Aire deficiency had the same effect on the pattern of the TSHR antibody response to immunization as in nontransgenics, although the amplitude of the response was lower in the transgenics. High-expressor A-subunit transgenics were unresponsive to immunization. We examined intrathymic expression of murine TSHR, thyroglobulin, and thyroid peroxidase (TPO), the latter two being the dominant autoantigens in Hashimoto’s thyroiditis (particularly TPO). Expression of the TSHR and thyroglobulin were reduced in the absence of Aire. Dramatically, thymic expression of TPO was nearly abolished. In contrast, the human A-subunit transgene, lacking a potential Aire-binding motif, was unaffected. Our findings provide insight into how varying intrathymic autoantigen expression may modulate thyroid autoimmunity and suggest that Aire deficiency may contribute more to developing Hashimoto’s thyroiditis than Graves’ disease.

scholarly journals Genetic studies on flagellum mutants of Chlamydomonas reinhardii

1972 ◽  
Vol 19 (2) ◽  
pp. 157-164 ◽  
Author(s):  
Anne McVittie
Keyword(s):  
Linkage Group ◽  
Wild Type ◽  
Linkage Groups ◽  
Genetic Studies ◽  
Chlamydomonas Reinhardii ◽  
The Third ◽  
Group Ii

SUMMARYEight newly isolated 9 + 0 mutants each mapped at one of the four previously known loci. Short flagellum mutants were at three loci, two of which (pf7 and pf8) were closely linked; the third, pf21, was unlinked to these two and mapped on linkage group II. The long flagellum mutants lf1 and lf2 were on linkage groups II and XII respectively. Mutants pf8A and lf1 were both recessive to wild-type. There was no evidence for non-Mendelian flagellum mutants.

scholarly journals Baseline Sensitivity of Natural Population and Resistance of Mutants in Phytophthora capsici to Zoxamide

2011 ◽  
Vol 101 (9) ◽  
pp. 1104-1111 ◽  
Author(s):  
Yang Bi ◽  
Xiaolan Cui ◽  
Xiaohong Lu ◽  
Meng Cai ◽  
Xili Liu ◽  
...  
Keyword(s):  
Ultraviolet Irradiation ◽  
Mycelial Growth ◽  
Laboratory Experiments ◽  
Phytophthora Capsici ◽  
Cross Resistance ◽  
Wild Type ◽  
Baseline Sensitivity ◽  
Mycelial Culture ◽  
Resistance Selection ◽  
Resistant Mutants

Laboratory experiments were conducted to determine the baseline sensitivity of Phytophthora capsici and its risk for developing resistance to zoxamide. In total, 158 P. capsici isolates were collected from China. All 158 isolates were sensitive to zoxamide, with effective concentrations for 50% inhibition of mycelial growth of 0.023 to 0.383 μg/ml and a mean of 0.114 μg/ml, which showed a skewed unimodal distribution. Zoxamide-resistant mutants of P. capsici were obtained by either treating mycelial culture and zoospores with ultraviolet irradiation or adapting a culture on zoxamide-amended plates. The frequency of resistance selection averaged 1.8 × 10–7. Resistant isolates were also derived by selfing or crossing two sexually compatible isolates, resulting in a mean selection frequency of 0.47. The resistance factor (RF) for zoxamide was 25 to 100 in P. capsici mutants. Through 10 culture transfers, the mutants maintained high levels of RF (between 14 and 134) and had almost equal fitness as their wild-type parents in mycelial growth, sporulation, and virulence. There was no cross resistance between zoxamide and either flumorph, metalaxyl, azoxystrobin, or etridiazole. Based on the results above, P. capsici can develop resistance to zoxamide, and the risk is predicted to be moderate in nature.

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