GENETICS AND PHYSIOLOGY OF THE XANTHOPHYLLOUS MUTANT OF THE TOMATO

1958 ◽  
Vol 36 (2) ◽  
pp. 251-267 ◽  
Author(s):  
L. Butler ◽  
L. O. Chang
Keyword(s):  
Light Intensity ◽  
Moment Method ◽  
Linear Trend ◽  
Lethal Effect ◽  
Lethal Effects ◽  
Green Is ◽  
Recessive Lethal ◽  
Early Seedling ◽  
Simple Product ◽  
Growing Conditions

Xanthophyllous is a dominant yellow-leafed mutant; the genotype Xa Xa is lethal in either the seed or the very early seedling stage, while the genotype Xa xa is viable but reacts differently to light intensity than does the normal xa xa plant. The 1: 2: 1 ratio is never realized because less than half the lethals appear as seedlings. The 2: 1 ratio is affected by germination so that under good conditions for germination a 2: 1 ratio is obtained, but under poor conditions the ratio may approach 1: 1. Maximum likelihood formulae are given for calculating linkage when one gene is a dominant with recessive lethal effects, and it is shown that the simple product moment method gives similar results for these data. Xa is in linkage group VII (chromosome 10), and its lethal effect disturbs the monogenic ratios of all genes in this group. The following crossover values between these genes and Xa are found: H 44.5%, pe 50%, t 35.5%, tv 31.7%, and ag 46.5%.Under standard growing conditions the pigment concentrations of xanthophyllous contrasted with green is: chlorophyll, 790 instead of 3240 μg./g.; xanthophyll, 54 instead of 211 μg./g.; and carotene, 60 instead of 130 μg./g. Both green and yellow plants, when grown under various intensities and spectral compositions of light, have different responses. Green plants make only limited response to changes in light intensity, whereas Xa xa plants become green and cannot be distinguished from xa xa plants. From 600 to 8000 ft-c. the Xa xa plants show a linear trend of decreasing pigment (increasing yellowness) with increasing light intensity. The hypothesis is advanced that Xa xa plants make as much pigment as do green ones, but a light-dependent reaction breaks down the pigments faster than they are being formed.

scholarly journals HIGH RATES OF OCCURRENCE OF SPONTANEOUS CHROMOSOME ABERRATIONS IN DROSOPHILA MELANOGASTER

Genetics ◽  
1976 ◽  
Vol 83 (2) ◽  
pp. 409-422
Author(s):  
Osamu Yamaguchi ◽  
Ricardo A Cardellino ◽  
Terumi Mukai
Keyword(s):  
Chromosome Aberrations ◽  
Gene Arrangement ◽  
Reciprocal Translocations ◽  
Lethal Effects ◽  
Recessive Lethal ◽  
The Third ◽  
Lethal Mutations ◽  
Pericentric Inversions ◽  
Break Points ◽  
Spontaneous Chromosome

ABSTRACT Spontaneous mutations were accumulated for 40 generations in 140 unrelated second chromosomes with the standard gene arrangement. These were extracted from the same population by using the marked inversion technique, and the following findings were obtained: (1) In 42 out of the 140 chromosome lines, chromosome aberrations were detected by examining the salivary gland chromosomes: 40 paracentric and 15 pericentric inversions, 2 reciprocal translocations between the second and the third chromosomes, and 6 transpositions. (2) In 63 out of the 90 originally lethal-free lines, recessive lethal mutations occurred. (3) There were only 3 lines that acquired chromosome aberrations (inversions) with no lethal effects in the homozygous condition. (4) In a comparison of these results with those of the (CH), (PQ), and (RT) chromosomes in which no chromosome aberrations occurred after accumulating mutations for 22058 chromosome·generations (Yamaguchi and Mukai 1974), it was concluded that some of these 140 chromosomes carried a kind of mutator. (5) The frequency of mutator-carrying chromosome lines was estimated to be 0.66 on the basis of the distribution of the break-points on the chromosome lines and the frequency of lines that acquired neither recessive lethal mutations nor chromosome aberrations. Thus, the average number of breaks per mutator-carrying chromosome was estimated to be about 0.19/generation. On the basis of these estimates, the nature of the mutator factor was discussed.

Bacterial Resistance to Ultrasonic Waves under Pressure at Nonlethal (Manosonication) and Lethal (Manothermosonication) Temperatures

1999 ◽  
Vol 65 (1) ◽  
pp. 297-300 ◽  
Author(s):  
R. Pagán ◽  
P. Mañas ◽  
J. Raso ◽  
S. Condón
Keyword(s):  
Heat Treatment ◽  
Listeria Monocytogenes ◽  
Synergistic Effect ◽  
Aeromonas Hydrophila ◽  
Salmonella Enteritidis ◽  
Bacterial Resistance ◽  
Lethal Effect ◽  
Ultrasonic Waves ◽  
Relative Pressure ◽  
Lethal Effects

ABSTRACT The decimal reduction times of Streptococcus faecium,Listeria monocytogenes, Salmonella enteritidis, and Aeromonas hydrophila corresponding to heat treatment at 62°C were 7.1, 0.34, 0.024, and 0.0096 min, and those corresponding to manosonication treatment (40°C, 200 kPa, 117 μm) were 4.0, 1.5, 0.86, and 0.90 min, respectively. The manosonication decimal reduction times of the four species investigated decreased sixfold when the amplitude was increased from 62 to 150 μm and fivefold when the relative pressure was raised from 0 to 400 kPa. In L. monocytogenes, S. enteritidis, and A. hydrophila, the lethal effect of manothermosonication was the result of the addition of the lethal effects of heat and manosonication, whereas in S. faecium it was a synergistic effect.

RESPONSE OF ONION (Allium cepa) TO OXYFLUORFEN DURING EARLY SEEDLING DEVELOPMENT

1985 ◽  
Vol 65 (2) ◽  
pp. 357-362 ◽  
Author(s):  
W. C. AKEY ◽  
V. SOUZA MACHADO
Keyword(s):  
Allium Cepa ◽  
Dry Weight ◽  
Epicuticular Wax ◽  
Seedling Development ◽  
Allium Cepa L ◽  
Growth Room ◽  
Early Seedling ◽  
Growing Conditions ◽  
Relationship Of ◽  
Early Seedling Development

The response of onion (Allium cepa L.) to postemergence applications of oxyfluorfen during early seedling development was measured in growth room experiments. Tolerance to oxyfluorfen increased more than 70-fold from the late loop to the two fully developed leaf stage. Field and growth room experiments were also conducted to determine the relationship of spray retention and epicuticular wax on the tolerance of onion seedlings to the herbicide. In general, there was a progressive decrease in spray retention and a corresponding increase in epicuticular wax per unit dry weight as plant age increased. Spray retention in the field was approximately twice as great as in the growth room. The amount of epicuticular wax on the leaf surfaces of the onions was about equivalent under the two growing conditions. A significant decrease in epicuticular wax per unit dry weight between the late one-leaf and late two-leaf stages occurred under both field and growth room conditions, while tolerance to the herbicide continued to increase during the same period.Key words: Onions, oxyfluorfen, ED50, spray retention, epicuticular wax

LINKAGE STUDIES IN TRIBOLIUM CASTANEUM. XI. THE MAP POSITION OF CHARCOAL, A PSEUDOALLELE OF BLACK

1978 ◽  
Vol 20 (1) ◽  
pp. 139-145 ◽  
Author(s):  
Eric Brown ◽  
Alexander Sokoloff
Keyword(s):  
Linkage Group ◽  
Tribolium Castaneum ◽  
Reciprocal Cross ◽  
Autosomal Dominant ◽  
Linkage Studies ◽  
Lethal Effects ◽  
Recessive Lethal ◽  
Reciprocal Crosses ◽  
Group Iii ◽  
Significant Difference

Charcoal, (Chr), an autosomal dominant with recessive lethal effects is located in linkage group III in Tribolium castaneum (Herbst). Its map position has been determined in respect to aureate (au), light ocular diaphragm (lod) and black (b). The distances between the various genes vary, depending on the sex of the cross. The Chr ++/+ lod au ♂ × +lod au/+lod au ♀ crosses give the following recombination values: au-lod = 22.19 ±.42%, Chr-lod = 20.03 ±.40% and Chr-au = 41.28 ±.49%. The reciprocal crosses give au-lod 28.08 ±.45%, Chr-lod = 17.67 ±.38% and Chr-au = 44.11 ±.50%. For the larger distances encompassed by the Chr-au region the recombination values in the two sexes were not significantly different. For the shorter distances the recombination values were significantly higher in the males than in the females in the au-lod region. They were not found to be significantly different in the Chr-lod region probably because of difficulty in identifying lod and non-lod beetles in the presence of Chr. Tests of allelism indicate that Chr and black b are pseudoalleles which recombine at a different rate in the two sexes. Chr +/+b ♂ × +b/+b ♀ gave 0.07% recombinants, while the reciprocal cross gave 0.014% recombinants, a significant difference. The data suggest that the order of the genes in this linkage group is Chr - b - lod - au.

scholarly journals HOMOEOSIS IN DROSOPHILA. I. COMPLEMENTATION STUDIES WITH REVERTANTS OF NASOBEMIA

Genetics ◽  
1973 ◽  
Vol 75 (2) ◽  
pp. 279-297
Author(s):  
R E Denell
Keyword(s):  
Drosophila Melanogaster ◽  
Lethal Effect ◽  
Complex Pattern ◽  
Chromosome 3 ◽  
Functional Interaction ◽  
Dominant Mutation ◽  
Recessive Lethal ◽  
Sex Comb

ABSTRACT A number of homoeotic mutants have been localized to the proximal right arm of chromosome 3 of Drosophila melanogaster. These include seven alleles of Antennapedia (Antp), which is associated with a transformation of antennae into legs; Nasobemia (Ns), which causes the same phenotype as Antp but was considered by Gehring (1966) not to be an allele; and three genes causing a transformation of second and third legs into first legs: Extra sex comb (Scx), Polycomb (Pc), and Multiple sex comb (Msc.). The alleles of Antp and Scx share a common recessive lethal effect, and Pc maps 0.2-0.3 units to the left of Scx.—In the present investigation, rearrangements associated with the reversion of Ns suggest that its cytological location is in or just distal to salivary chromosome doublet 84B1-2. Although Ns is viable when homozygous, four of its revertants share a common recessive lethal effect. These revertants fail to complement the recessive lethality of AntpB and Scx. Furthermore, they show a complex pattern of functional interaction with Pc and with Humeral (Hu), a dominant mutation associated with a rearrangement with one breakpoint just distal to 84B1-2. Finally, analysis of a revertant of Msc indicates that Msc is also located very close to 84B1-2. It is concluded that Ns and Scx are alleles of Antp. Pc shows many functional similarities to the Antp locus, but is probably not allelic. Evidence is presented that these dominant homoeotic genes are neomorphic in nature.

scholarly journals Construction and assessment of a low cost NDVI sensor

2019 ◽  
Author(s):  
Rafaella Pironato Amaro ◽  
Luiz Henrique Antunes Rodrigues ◽  
Felipe Ferreira Bocca
Keyword(s):  
Light Intensity ◽  
Monitoring System ◽  
Low Cost ◽  
High Capacity ◽  
Low Correlation ◽  
Growing Conditions ◽  
Cost Components ◽  
Temporal Inconsistency

Given the potential of low cost sensors for agriculture, a monitoring system with low cost components was constructed to evaluate its capacity to detect variations in vegetative vigor in smooth lettuce seedlings under different growing conditions. The results showed temporal inconsistency and low variability in NDVI values. The inconsistency can be attributed mainly to factors such as luminosity and the high capacity of retention of water and nutrients of the substrate. Days with milder light intensity produced potentially better NDVI values. The low variability of NDVI eventually contributed to its low correlation with mass.

scholarly journals Protease-Deficient DegP Suppresses Lethal Effects of a Mutant OmpC Protein by Its Capture

2003 ◽  
Vol 185 (1) ◽  
pp. 148-154 ◽  
Author(s):  
Maria CastilloKeller ◽  
Rajeev Misra
Keyword(s):  
Outer Membrane ◽  
Proteolytic Activity ◽  
Disulfide Bonds ◽  
Outer Membrane Proteins ◽  
Lethal Effect ◽  
Wild Type ◽  
Lethal Effects ◽  
Assembly Pathway ◽  
Negative Effect ◽  
Protease Deficient

ABSTRACT The expression of assembly-defective outer membrane proteins can confer lethality if they are not degraded by envelope proteases. We report here that the expression of a mutant OmpC protein, OmpC2Cys, which forms disulfide bonds in the periplasm due to the presence of two non-native cysteine residues, is lethal in cells lacking the major periplasmic protease, DegP. This lethality is not observed in dsbA strains that have diminished ability to form periplasmic disulfide bonds. Our data show that this OmpC2Cys-mediated lethality in a degP::Kmr dsbA + background can be reversed by a DegP variant, DegPS210A, that is devoid of its proteolytic activity but retains its reported chaperone activity. However, DegPS210A does not reverse the lethal effect of OmpC2Cys by correcting its assembly but rather by capturing misfolded mutant OmpC polypeptides and thus removing them from the assembly pathway. Displacement of OmpC2Cys by DegPS210A also alleviates the negative effect that the mutant OmpC protein has on wild-type OmpF.

Effect of Selection on Whaxy: An Autosomal Dominant Mutation in the Screw- Worm Fly with Recessive Lethal Effects

1965 ◽  
Vol 99 (904) ◽  
pp. 47-57
Author(s):  
Leo E. LaChance ◽  
D. E. Hopkins
Keyword(s):  
Autosomal Dominant ◽  
Dominant Mutation ◽  
Lethal Effects ◽  
Recessive Lethal

scholarly journals The delayed lethal effect of radium on tissue cultures in vitro —Comparison of continuous and spaced radiation

1931 ◽  
Vol 108 (756) ◽  
pp. 190-195 ◽  
Keyword(s):  
Lethal Effect ◽  
Survival Period ◽  
Tissue Cultures ◽  
Lethal Effects ◽  
Continuous Irradiation ◽  
In Vitro Comparison

In a previous paper (Spear, 1930) I have described the delayed lethal effects or radium on tissue cultures in vitro . Two quantities of radium were used in the experiments—100 mg. and 300 mg.—and exposures varied from 3 hours up to 24 hours. It was found that when a delayed lethal effect followed exposure to radium, it occurred sooner in those cultures which had been exposed to the greater intensity of radiation for a shorter time than in those subjected to the lesser intensity for a longer time, the product of milligrams of radium and hours of exposure being constant in a given comparison. The following experiments were made to compare the length of the survival period of cultures exposed to a continuous irradiation known to be lethal, with the survival period following exposure to a spaced radiation of the same intensity.

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