scholarly journals RECOMBINATION IN THE VICINITY OF INSERTIONS OF TRANSPOSON Tn5 IN MYXOCOCCUS XANTHUS

Genetics ◽  
1983 ◽  
Vol 105 (2) ◽  
pp. 281-291
Author(s):  
Erica Sodergren ◽  
Yvonne Cheng ◽  
Leon Avery ◽  
Dale Kaiser
Keyword(s):  
Genetic Recombination ◽  
Recombination Frequency ◽  
Myxococcus Xanthus ◽  
Physical Distance ◽  
The Other ◽  
Restriction Map ◽  
Transposon Tn5 ◽  
Good Correspondence ◽  
Reciprocal Crosses ◽  
Two Measures

ABSTRACT To test genetic recombination in the vicinity of insertions of the transposon Tn5, crosses were performed by transduction between M. xanthus strains carrying different insertions of Tn5. One member of each pair carried resistance to kanamycin (Tn5-Km); the other carried resistance to tetracycline (Tn5-Tc). The distance between each pair of Tn5 insertions was also measured by restriction mapping. The physical distance corresponding to each recombination frequency was calculated from the transductional linkage and compared with distance on the restriction map. A good correspondence between the two measures of distance was obtained for a pair of Tn5 insertions near the cglB locus and for another pair near the mgl locus. Correspondence between the two measurements of distance, the observed allelic behavior of Tn5-Km and Tn5-Tc at the same locus and the finding of the same frequencies of recombinants in reciprocal crosses implied that recombination in the vicinity of Tn5 was normal.

scholarly journals GENETIC CONTROL OF MEIOSIS IN RICE, ORYZA SATIVA L. III. EFFECT OF DS GENES ON GENETIC RECOMBINATION

Genetics ◽  
1984 ◽  
Vol 108 (3) ◽  
pp. 697-706
Author(s):  
Kunio Kitada ◽  
Takeshi Omura
Keyword(s):  
Oryza Sativa ◽  
Chiasma Frequency ◽  
Genetic Recombination ◽  
Recombination Frequency ◽  
Oryza Sativa L ◽  
The Other ◽  
Crossing Over ◽  
Homozygous Condition ◽  
Synaptonemal Complexes ◽  
The Mean

ABSTRACT The recombination frequency as influenced by five independent recessive ds genes was measured on three segments of different chromosomes of rice, Oryza sativa L. Each ds gene in the homozygous condition resulted in an almost equally reduced recombination frequency in the three segments. When the mean reduction in recombination frequency was related to the reduction of chiasma frequency, the five ds genes were divided into two types: in one type the reduction of chiasma frequency almost corresponded to the mean reduction of recombination frequency, and in the other the chiasma frequency was greatly reduced in comparison with the mean reduction of recombination frequency. Three of the five ds genes were found to belong to the former group. In both types, normal synaptonemal complexes were observed in pachytene cells homozygous for ds genes. This finding suggests that ds genes do not affect the formation of synaptonemal complexes which are regarded as the prerequisite structure for crossing over.

scholarly journals act Operon Control of Developmental Gene Expression in Myxococcus xanthus

2002 ◽  
Vol 184 (4) ◽  
pp. 1172-1179 ◽  
Author(s):  
Thomas M. A. Gronewold ◽  
Dale Kaiser
Keyword(s):  
Fruiting Body ◽  
Myxococcus Xanthus ◽  
The Other ◽  
Loss Of Function ◽  
Wild Type ◽  
Developmental Gene ◽  
Developmental Gene Expression ◽  
Mutant Strains ◽  
Genes Encoding ◽  
Signal Production

ABSTRACT Cell-bound C-signal guides the building of a fruiting body and triggers the differentiation of myxospores. Earlier work has shown that transcription of the csgA gene, which encodes the C-signal, is directed by four genes of the act operon. To see how expression of the genes encoding components of the aggregation and sporulation processes depends on C-signaling, mutants with loss-of-function mutations in each of the act genes were investigated. These mutations were found to have no effect on genes that are normally expressed up to 3 h into development and are C-signal independent. Neither the time of first expression nor the rate of expression increase was changed in actA, actB, actC, or actD mutant strains. Also, there was no effect on A-signal production, which normally starts before 3 h. By contrast, the null act mutants have striking defects in C-signal production. These mutations changed the expression of four gene reporters that are related to aggregation and sporulation and are expressed at 6 h or later in development. The actA and actB null mutations substantially decreased the expression of all these reporters. The other act null mutations caused either premature expression to wild-type levels (actC) or delayed expression (actD), which ultimately rose to wild-type levels. The pattern of effects on these reporters shows how the C-signal differentially regulates the steps that together build a fruiting body and differentiate spores within it.

GENETIC RECOMBINATION IN SEXUAL CROSSES OF PHYCOMYCES

Genetics ◽  
1975 ◽  
Vol 80 (3) ◽  
pp. 445-462
Author(s):  
A P Eslava ◽  
M I Alvarez ◽  
Patricia V Burke ◽  
M Delbrück
Keyword(s):  
Mating Type ◽  
Genetic Recombination ◽  
Recombination Frequency ◽  
Intragenic Recombination ◽  
Phycomyces Blakesleeanus ◽  
Sexual Crosses ◽  
Color Marker ◽  
Three Factor

ABSTRACT Sexual crosses between strains of Phycomyces blakesleeanus, involving three auxotrophic and one color marker and yielding a high proportion of zygospore germination, are described. Samples of 20-40 germ spores from 311 individual fertile germ sporangia originating from five two-factor and three three-factor crosses were characterized. The results show: (1) absence of any contribution of apogamic nuclei to the progeny, (2) confirmation of Burgeff's conjecture that the germ spores of any germ sporangium in most cases derive from one meiosis. In a cross involving two allelic markers the analysis of 175 pooled germ sporangia suggests an intragenic recombination frequency of 0.6%. All other factor combinations tested are unlinked. The bulk of the germ spores are homokaryotic. However, a small portion (4%) are heterokaryotic with respect to mating type.

scholarly journals Comparison of Behavioral and Physiological Measures of the Status of the Cochlear Nonlinearity

2021 ◽  
Vol 25 ◽  
pp. 233121652110161
Author(s):  
Michal Fereczkowski ◽  
Torsten Dau ◽  
Ewen N. MacDonald
Keyword(s):  
Otoacoustic Emissions ◽  
Hearing Impaired ◽  
Good Correspondence ◽  
Cochlear Nonlinearity ◽  
Temporal Masking ◽  
The Status ◽  
Peripheral Compression ◽  
Two Measures ◽  
Peripheral Nonlinearity ◽  
Fitting In

While an audiogram is a useful method of characterizing hearing loss, it has been suggested that including a complementary, suprathreshold measure, for example, a measure of the status of the cochlear active mechanism, could lead to improved diagnostics and improved hearing-aid fitting in individual listeners. While several behavioral and physiological methods have been proposed to measure the cochlear-nonlinearity characteristics, evidence of a good correspondence between them is lacking, at least in the case of hearing-impaired listeners. If this lack of correspondence is due to, for example, limited reliability of one of such measures, it might be a reason for limited evidence of the benefit of measuring peripheral compression. The aim of this study was to investigate the relation between measures of the peripheral-nonlinearity status estimated using two psychoacoustical methods (based on the notched-noise and temporal-masking curve methods) and otoacoustic emissions, on a large sample of hearing-impaired listeners. While the relation between the estimates from the notched-noise and the otoacoustic emissions experiments was found to be stronger than predicted by the audiogram alone, the relations between the two measures and the temporal-masking based measure did not show the same pattern, that is, the variance shared by any of the two measures with the temporal-masking curve-based measure was also shared with the audiogram.

Genetic Recombination in Coprinus

1970 ◽  
Vol 6 (3) ◽  
pp. 669-678
Author(s):  
B. C. LU
Keyword(s):  
Fruiting Body ◽  
Temperature Effects ◽  
Cold Shock ◽  
Genetic Recombination ◽  
Recombination Frequency ◽  
Temperature Treatment ◽  
Sensitive Period ◽  
Crossing Over ◽  
Synaptinemal Complex ◽  
Before And After

The frequency of genetic recombination in Coprinus lagopus may be modified by heat and cold shock. By removal of samples from a fruiting body before and after temperature treatment, it is possible to study the ultrastructure of chromosomes at the time recombination frequency (between den+ x +me-1) can be modified. The sensitive period for temperature effects and, therefore, probably the time of crossing over, commences with the formation of the synaptinemal complex (S.C.) and ends with its disappearance, i.e. during the entire existence of the S.C. It is concluded that recombination is an event subsequent to the formation of the S.C. and is independent of the process of its formation. It is suggested that the event takes place at the synaptic centre.

scholarly journals An outside view: What do observers say about others’ races and Hispanic origins?

2017 ◽  
Author(s):  
Sonya Rastogi ◽  
CAROLYN LIEBLER ◽  
James Noon
Keyword(s):  
American Indians ◽  
Alaska Native ◽  
Pacific Islander ◽  
The Other ◽  
People Of Color ◽  
Hispanic Origin ◽  
Census 2000 ◽  
Two Measures ◽  
Data Source ◽  
Observer Identification

Outsiders’ views of a person’s race or Hispanic origin can impact how she sees herself, how she reports her race and Hispanic origins, and her social and economic experiences. The way outsiders describe non-strangers in terms of their race and Hispanic origin may reveal popular assumptions about which race/Hispanic categories are salient for Americans, which kinds of people are seen as multiracial, and the types of cues people use when identifying another person’s race. We study patterns of observer identification using a unique, large, linked data source with two measures of a person’s race and Hispanic origin. One measure (from Census 2000 or the 2010 Census) was provided by a household respondent and the other (from the other census year) was provided by a census proxy reporter (e.g., a neighbor) who responded on behalf of a non-responsive household. We ask: Does an outsider’s report of a person’s race and Hispanic origin match a household report? We find that in about 90% of our 3.7 million (nonrepresentative) cases, proxy reports of a person’s race and Hispanic origin match responses given by the household in a different census year. Match rates are high for the largest groups: non-Hispanic whites, blacks, and Asians and for Hispanics, though proxies are not very able to replicate the race responses of Hispanics. Matches are much less common for people in smaller groups (American Indian/Alaska Native, Pacific Islander, Some Other Race, and multiracial). We also ask: What predicts a matched response and what predicts a particular unmatched response? We find evidence of the persistence of hypodescent for blacks and hyperdescent for American Indians. Biracial Asian-whites and Pacific Islander-whites are more often seen by others as non-Hispanic white than as people of color. Proxy reporters tend to identify children as multiple race and elders as single race, whether they are or not. The race/Hispanic composition of the tract is more powerfully predictive of a particular unmatched response than are tract-level measures of socioeconomic status; unmatched responses are often consistent with the race/Hispanic characteristics of the neighborhood.

The Relationship between Death Anxiety and Mental Health/Distress

1991 ◽  
Vol 22 (1) ◽  
pp. 13-24 ◽  
Author(s):  
William White ◽  
Paul J. Handal
Keyword(s):  
Mental Health ◽  
Death Anxiety ◽  
The Other ◽  
Health Distress ◽  
High Death ◽  
Two Measures ◽  
Methodological Problems ◽  
Mental Health Distress ◽  
The Relationship ◽  
Interpretation Of Results

This study systematically examined the relationship between death anxiety and mental health/distress and controlled for methodological problems present in the literature. Specifically, two measures of death anxiety were used-both had recommended cut-off scores for high death anxiety. Both positive and negative aspects of adjustment were assessed, and a valid clinically meaningful cut-off score for distress was employed. Results revealed high death-anxious females were statistically and clinically more distressed and were significantly less satisfied with life than low death-anxious females. Similar results were obtained for males on one death-anxiety measure; a similar trend was found on the other measure. Discussion focuses on the interpretation of results.

Research on the Optimization of the Offset and the Power Consumption for a DP Assisted Mooring System

2013 ◽  
Author(s):  
Hongchao Wang ◽  
Lei Wang ◽  
Hanlin Liu
Keyword(s):  
Power Consumption ◽  
The Other ◽  
Engineering Practice ◽  
Dynamic Positioning ◽  
Positioning System ◽  
Mooring System ◽  
Mooring Lines ◽  
Positioning Accuracy ◽  
Dynamic Positioning System ◽  
Two Measures

DP assisted mooring system is a new positioning system including mooring system and dynamic positioning system. In this paper, two measures are proposed to reduce the offset and the power consumption of a generic semi-submersible platform which is equipped with a DP assisted mooring system during operation. One is to tighten the windward mooring lines and slacken the leeward mooring lines, the other is to reduce or cancel the forbidden angles of the thrusters adjacent to the failed thrusters. Given that the two measures can both reduce the offset and the power consumption of the semi-submersible unit, it is suggested to combine the two measures together to obtain better positioning accuracy. This paper is helpful to engineering practice.

Effects of Posthypnotic Suggestion on Perceived Egocentric Distance

Perception ◽  
1980 ◽  
Vol 9 (5) ◽  
pp. 561-568 ◽  
Author(s):  
Peter J MacCracken ◽  
Walter C Gogel ◽  
Gerald S Blum
Keyword(s):  
Indirect Method ◽  
Cognitive Biases ◽  
Direct Method ◽  
Verbal Report ◽  
Physical Distance ◽  
The Other ◽  
Egocentric Distance ◽  
Indirect Measures ◽  
Experimental Trials ◽  
Posthypnotic Suggestion

The effects of posthypnotic suggestion on the perception of egocentric distance were evaluated by two methods, one direct and the other indirect. The direct method was the verbal report of the perceived distance of the stimulus. The indirect method used a measure based on apparent concomitant motion of the stimulus with a lateral movement of the head. The indirect method, unlike the direct method, has been shown to be insensitive to cognitive biases. Two highly trained hypnotic observers received posthypnotic suggestions to see a point of light at approximately 2, 4, or 6 ft (61, 122, or 183 cm) from themselves. For each suggested distance the light was physically at 2, 4, or 6 ft. As a control, trials were completed using these same physical distances without the posthypnotic suggestions. Nine experimental trials, one for each combination of suggested distance and physical distance, constituted a trial set. One observer completed three sets, and the other completed two sets. It was found that the posthypnotic suggestions affected the direct but not the indirect measures of the perceived distances of the light.

scholarly journals Non-mendelian female sterility in Drosophila melanogaster: variations of chromosomal contamination when caused by chromosomes of various inducer efficiencies

1978 ◽  
Vol 32 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Alain Pélisson
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Recombination ◽  
Laboratory Strain ◽  
The Other ◽  
Female Sterility ◽  
Genetic Element ◽  
Specific Kind ◽  
Classical Genetic ◽  
Apparent Change

SUMMARYA quite specific kind of sterile F1 female, called SF females, arises only when females of strains denoted reactive are crossed with males of the other class (inducer). It was previously shown that this sterility results from a nucleocytoplasmic interaction between the maternal reactive cytoplasm and a factor, called I, which may be born by any one of the paternal chromosomes. In SF females, but not in their brothers, a varying proportion of reactive chromosomes are able to acquire irreversibly the I factor, independently of any classical genetic recombination with the inducer chromosome(s). During this process, called chromosomal contamination, the contaminating chromosome(s) do not undergo any apparent change. The present paper deals with the efficiency of both original inducer and contaminated chromosomes to yield a more or less intense SF sterility. The Otanu inducer laboratory strain contains at least two types of X chromosomes (called strong and weak) which differ genetically with respect to their inducer efficiency. Reactive third chromosomes were contaminated by these strong or weak X chromosomes and their inducer efficiencies compared. Results show that they are on average stronger when they have been contaminated by strong X chromosomes than when contaminated by weak ones. Such a correlation favours the hypothesis that chromosomal contamination is due to the insertion of some genetic element(s) into reactive chromosomes.

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