bluuebunny/crossref_metadata_2025_split huggingface dataset:
A CIS-DOMINANT MUTATION IN ASPERGILLUS NIDULANS AFFECTING THE EXPRESSION OF THE amdS GENE IN THE PRESENCE OF MUTATIONS IN THE UNLINKED GENE, amdA
Authors: Hynes Michael J 
Published: January 2021

ABSTRACT
A mutant producing very high levels of the acetamidase enzyme encoded by the amdS gene has been isolated in a strain containing the amdA7 mutation, which itself causes high levels of this enzyme. Genetic analysis has shown that this mutation, designated amdI66, is adjacent to the amdS gene and is cis-dominant in its effect. The amdI66 mutation has little effect on amdS expression when present in strains not containing the amdA7 mutation. Two other amdA mutations investigated also interact with the amdI66 mutation to result in high acetamidase levels. No interaction between amdI66 and any of the other putative regulatory genes affecting amdS expression has been observed. The amdI66 mutation has been located by fine structure mapping at the extreme end of the controlling region, which has previously been defined by genetic mapping (Hynes 1979). Analysis of this region has been extended by mapping new mutations resulting in loss of amdS expression. One of these defines the most extreme site capable of mutation to loss of gene function found so far.
NATURALLY OCCURRING ENZYME ACTIVITY VARIATION IN DROSOPHILA MELANOGASTER. II. RELATIONSHIPS AMONG ENZYMES
Authors: Wilton A N , Laurie-Ahlberg C C , Emigh T H , Curtsinger J W 
Published: January 2021

ABSTRACT
This report describes an investigation of the specificities of the genetic effects, caused by whole chromosome substitution, on the activities of 23 enzymes in Drosophila melanogaster. Two types of correlation estimates are examined, the product-moment correlation over the chromosome substitution line means and the corresponding correlation of line effects, which is a standardized covariance component estimate. The two types of correlations give very similar results. Although there is ample evidence for specific line effects on individual enzyme activities, there are extensive intercorrelations among many of the enzymes for both second- and third-chromosome substitution lines. The pattern of correlations with respect to the metabolic functions or other properties of the enzymes is difficult to visualize by inspection of the correlation matrix, so a multivariate graphical technique, the biplot (Gabriel 1971), was employed to obtain a two-dimensional view of relationships among the enzyme activities. The second and third chromosome lines show similar patterns. Four of the five mitochondrial enzymes form one highly intercorrelated group whereas another highly intercorrelated group contains several cytosolic enzymes. Within the cytosolic group, particularly high correlations are observed between enzymes that have glucose 6-phosphate as a substrate or product and between enzymes that are NADP-dependent. Although the pattern of intercorrelations is not clearly explicable in terms of metabolic relationships among the enzymes, there is some tendency for enzymes that catalyze sequential reactions or share a substrate or product to have correlated activity levels.
THE EXPERIMENTAL ASSESSMENT OF FITNESS IN DROSOPHILA. I. COMPARATIVE MEASURES OF COMPETITIVE REPRODUCTIVE SUCCESS
Authors: Haymer David S , Hartl Daniel L 
Published: January 2021

ABSTRACT
Strains of D. melanogaster, representing a range of genetic diversity, were systematically subjected to each of several techniques that have been devised to assess total or net fitness. All of these techniques operationally define fitness in terms of reproductive success under competitive conditions. For the set of strains tested, an excellent correlation was obtained between the competitive indices produced by two single-generation intraspecific competitions, despite fundamental differences in the strains used as competitive standards. The results of two interspecific tests were also correlated, but the intraspecific vs. interspecific test result comparisons ranged from highly significant to nonsignificant correlations. For the fitness estimates, the overall variances produced by the intraspecific tests were greater than those obtained in the interspecific competitions. No significant correlations were found between the results of a long-term (multi-generation) competitive assessment of fitness and any of the single-generation tests. Therefore, although all of these tests refer to a net parameter called "fitness", they are clearly not all measuring the same thing. Differences in the competitive interactions operative in each technique are suggested to account for these results.
MEIOTIC CHROMOSOME BEHAVIOR INFLUENCED BY MUTATION-ALTERED DISJUNCTION IN DROSOPHILA MELANOGASTER FEMALES
Authors: O′Tousa Joseph 
Published: January 2021

ABSTRACT
The effects of a female-specific meiotic mutation, altered disjunction (ald: 361), are described. Although ald females show normal levels of meiotic exchange, sex- and 4th-chromosome nondisjunction occurs at an elevated level. A large proportion of the nondisjunction events is the result of nonhomologous disjunction of the sex and 4th chromosomes. These nonhomologous disjunction events, and probably all nondisjunction events occurring in ald females, are the result of two anomalies in chromosome behavior: (1) X chromosomes derived from exchange tetrads undergo nonhomologous disjunction and (2) the 4th chromosomes nonhomologously disjoin from larger chromosomes. There is at best a marginal effect of ald on the meiotic behavior of chromosomes 2 or 3. The results suggest that the ald + gene product acts to prevent the participation of exchange X chromosomes and all 4th chromosomes in nonhomologous disjunction events. The possible role of ald + in current models of the disjunction process is considered.
VARIATION IN AMYLASE HAPLOTYPES AMONG CONGENIC LINES OF THE HOUSE MOUSE
Authors: Nielsen J Tonnes 
Published: January 2021

ABSTRACT
Pancreatic amylase in the mouse displays considerable quantitative genetic variation. Agar gel electrophoresis reveals that homozygous animals have either one form of the enzyme, type A, or two forms, type AB. Only few animals have been found that contradict this statement, namely among Mus musculus castaneus from Thailand, which has a single-banded B type. Double-banded homozygous specimens of various origins have different relative proportions of the two isoenzymes. By measuring the A:B ratios in such animals, a number of distinct haplotypes or amylase complexes, determining ratios ranging from 61% A:39% B to 12% A:88% B, have been recognized. These complexes differ also with respect to the total amount of amylase produced. If the reference stock C3H/As is given the value 1, then other haplotypes have values ranging from 1.0 to 0.27. Nineteen amylase haplotypes have been established in congenic lines on a C3H/As background. Some of these lines contain at least four active pancreatic amylase structural genes and breeding experiments have demonstrated that the genetic elements regulating total amylase production and relative proportions of the isoenzymes are located within the amylase complex, cis-acting, and very closely linked to the structural genes.
DUMPY MUTATIONS FOLLOWING X-IRRADIATION OF DROSOPHILA MELANOGASTER MATURE SPERM IN OXYGEN OR IN NITROGEN
Authors: Miyamoto Tomio 
Published: January 2021

ABSTRACT
A comparison was made of the oxygen enhancement pattern among the different kinds of dumpy mutations (olv, ov, ol, lv, o and v types), yellow mutations on the scute-8 chromosome, white, miniature and forked mutations, and the marker losses in the doubly marked Y chromosome [BS Y sc 8 (y +)], all of which were induced by X rays in mature sperm of Drosophila melanogaster. The results indicate that (1) an essential difference does not exist in the oxygen enhancement pattern between the different kinds of dumpy mutations, except for the ov exceptions. For these exceptions, relatively high enhancement by oxygen is elucidated; (2) a similarity exists in the oxygen enhancement pattern among the different kinds of dumpy mutations (except for the ov exceptions), yellow, miniature and forked mutations, and BS and y + marker losses; and (3) the oxygen enhancement pattern elucidated for the ov exceptions is similar to that for the white mutations. These findings suggest that the nature of the different kinds of dumpy mutations is not different from one another, except for the ov exceptions, and that except for these ov exceptions and the white mutations, there seems to be some kind of similarity in the nature of mutation among the different kinds of mutations studied.
GENETIC RECOMBINATION AT THE BUFF SPORE COLOR LOCUS IN SORDARIA BREVICOLLIS. II. ANALYSIS OF FLANKING MARKER BEHAVIOR IN CROSSES BETWEEN BUFF MUTANTS
Authors: Sang Helen , Whitehouse Harold L K 
Published: January 2021

ABSTRACT
Aberrant asci containing one or more wild-type spores were selected from crosses between pairs of alleles of the buff locus in the presence of closely linked flanking markers. Data were obtained relating to the site of aberrant segregation and the position of any associated crossover giving recombination of flanking markers. Aberrant segregation at a proximal site within the buff gene may be associated with a crossover proximal to the site of aberrant segregation or, with equal frequency, with a crossover distal to the site of the second mutant present in the cross. Similarly, segregation at a distal site may be associated with a crossover distal to the site or, with lower frequency, with a crossover proximal to the site of the proximal mutant present in the cross. Crossovers between the alleles were rare. This evidence for the relationship between hybrid DNA and crossing over is discussed in terms of current models for the mechanism of recombination.
ACTIVITY OF PLASMID REPLICONS IN CAULOBACTER CRESCENTUS: RP4 AND ColE1
Authors: O'Neill Edward A , Berlinberg Craig , Bender Robert A 
Published: January 2021

ABSTRACT
The RP4 replicon was detected as covalently-closed circular DNA in Caulobacter crescentus strains into which it had been transferred from Escherichia coli. RP4-mediated transfer of ColE1-associated markers into C. crescentus occurred, but only as the result of transposon-mediated events. Both transposition of a ColE1-associated marker onto RP4 and cointegration of ColE1 with RP4 were observed. Chimeric plasmids containing both a ColE1 and an RP4 origin of replication were stably maintained in C. crescentus, but similar plasmids lacking the RP4 origin of replication were not stably maintained in C. crescentus. Thus we show that the ColE1 replicon cannot be maintained in C. crescentus unless it is covalently linked to another replicon, such as RK2, that can be maintained.
RELATIONS BETWEEN FACTORS CONTROLLING CROSSING OVER AND MUTABILITY IN MALES OF DROSOPHILA ANANASSAE
Authors: Hinton Claude W 
Published: January 2021

ABSTRACT
Several stocks, selected because they carried previously identified factors governing either crossing over in males or mutability, were examined to determine whether the effects of these factors are restricted to one or the other process. Neither of two dominant enhancers of male crossing over had detectable effects on Minute mutation frequencies among progenies of assayed F1 males. Genetically equivalent F1 males monitored for crossing over showed no unequivocal effect of either of three mutators (two dominant and one extrachromosomal) or of a suppressor of mutability. However, one combination of a dominant crossover enhancer with a dominant mutator showed synergistic increases in both crossover and Minute frequencies, and the possibility exists that a single extrachromosomally transmitted element suppresses both male crossing over and mutability. This suppressor element (or elements) had been previously diagnosed in the pc stock which, in this study, was discovered to have also a dominant enhancer of male crossing over and a dominant mutator occupying separable loci in the third chromosome. The pc enhancer of male crossing over differs from the dominant enhancer in another stock with respect to the regional distribution of crossovers, and the pc mutator is distinguished from another 3-linked mutator by its preferential induction of mutations at the Delta locus.
EVIDENCE FOR BALANCING SELECTION AT HLA
Authors: Hedrick Philip W , Thomson Glenys 
Published: January 2021

ABSTRACT
HLA data from the A and B loci for 22 populations were compared with the neutrality expectations from Ewens' sampling theory. In 25 of 44 cases, there was significantly less homozygosity than expected. Although a number of factors can affect homozygosity in this manner, upon close examination only symmetrical balancing selection appears to be consistent with these data.
BALANCING SELECTION, INVERSION POLYMORPHISM AND ADAPTATION IN DDT-RESISTANT POPULATIONS OF DROSOPHILA MELANOGASTER
Authors: Barnes Phillip T 
Published: January 2021

ABSTRACT
The modes of selection important in maintaining an inversion-allozyme polymorphism in two laboratory populations of Drosophila melanogaster were examined. The populations, 731R and J2, are highly resistant to DDT. The polymorphism involves the Standard and In(3R)P chromosomal arrangements in very strong linkage association with the AO 1 and AO 4 allozymes, respectively, of the aldehyde oxidase locus—The mean fertilities of the three karyotypes were not significantly different in 731R, but, in J2, In/In was significantly inferior to St/St and St/In. Egg-to-adult viability tests indicated very strong heterozygote advantage at all frequency combinations of the karyotypes in both populations when DDT was present. When DDT was excluded, the viabilities varied over the frequency combinations but were not inversely correlated with karyotype frequency, as predicted by balancing frequency-dependent selection. Discrete, multiple-generation experiments showed a rapid increase in heterozygote frequency to about 80% in both populations when DDT was present. Without DDT, 731R showed apparent directional selection favoring St, whereas J2 showed persistence of the polymorphism, although with extensive fluctuation.—Thus, the inversion-allozyme polymorphism is directly involved in the adaptation to a specific environmental component, DDT, and the selective advantage of the heterozygotes is the important balancing force. Balancing frequency-dependent selection was not observed, which suggests the hypothesis that this form of selection may not be involved in adaptation to novel environmental conditions.
GENETICS OF YEAST GLUCOKINASE
Authors: Maitra P K , Lobo Zita 
Published: January 2021

ABSTRACT
Mutants of Saccharomyces cerevisiae lacking glucokinase (EC 2.7.1.2) have no discernible phenotypic difference from the wild-type strain; in a hexokinaseless background, however, they are unable to grow on any sugar except galactose. Reversion studies with glucokinase mutants indicate that the yeast S. cerevisiae has no other enzyme for phosphorylating glucose except the two hexokinases, P1 and P2, and glucokinase. Spontaneous revertants of hxk1 hxk2 glk1 strains collected on glucose regain any one of these three enzymes. The majority of glucokinase revertants synthesize species of enzyme activity that are kinetically or otherwise indistinguishable from the wild-type enzyme. In a few cases the reverted enzyme is very perceptibly altered in properties with a Km for glucose two orders of magnitude higher than that of the enzyme from the wild-type parent. These recessive, noncomplementing mutants, thus, define a single structural gene GLK1 of glucokinase. Yeast diploids lacking all of the three enzymes for glucose phosphorylation fail to sporulate. Heterozygosity of either of the hexokinase genes HXK1 or HXK2, but not GLK1, restores sporulation. The location of GLK1 on chromosome III was indicated by loss of this chromosome when hexokinaseless diploids heterozygous for glk1 were selected for resistance to 2-deoxyglucose; the homologue of chromosome III carrying GLK1, the mating-type allele and other nutritional markers on this chromosome was lost. Meiotic mapping of glucokinase executed with heterozygosity of one of the hexokinases indicated that the gene GLK1 defining the structure of glucokinase protein is located on the left arm of chromosome III 24 cM to the left of his4 in the order: leu2—his4—glk1.—Only two of 206 independent glucokinase mutants are nonsense ochre, both of which map at one end of the gene. In hxk1 only one of 130 isolates is a nonsense mutation, whereas in hxk2 none has been found among 220 independent mutants. These results raise the possibility that the protein products of these genes have some other essential function.—An earlier mapping result for hxk2 has been corrected. The new location is on the left arm of chromosome VII, 17 cM distal to ade5 in the order: lys5—ade5—hxk2.
ANALYSES OF THE AGE OF GENES AND THE FIRST ARRIVAL TIMES IN A FINITE POPULATION
Authors: Maruyama Takeo , Fuerst Paul A 
Published: January 2021

ABSTRACT
The age of a mutant gene is studied using the infinite allele model in which every mutant is new and selectively neutral. Based on a time reversal theory of Markov processes, we develop a method of mathematical analysis that is considerably simpler for calculating the various statistics of the age than previous methods. Formulas for the mean and variance and for the distribution of age are presented together with some examples of relevance to cases in natural populations.—Theoretical studies of the first arrival time of an allele to a specified frequency, given an initially monomorphic condition of the locus, are presented. It is shown that, beginning with an allele that has frequency p = 1 or an allele with frequency p = 1/2N, there is an initial lag phase in which there is virtually no chance of an allele with a specified intermediate frequency appearing in the population. The distribution of the first arrival time is also presented. The distribution shows several characteristics that are not immediately obvious from a consideration of only the mean and variance of first arrival time. Especially noteworthy is the existence of a very long tail to the distribution. We have also studied the distribution of the age of an allele in the population. Again, the distribution of this measure is shown to be more informative for several questions than are the mean and variance alone.
Expanded Supercooling Capacity With No Cryoprotectant Accumulation Underlies Cold Tolerance of the European Grapevine Moth
Authors: Masoudmagham Ashraf , Izadi Hamzeh , Mohammadzadeh Mojgan 
Published: January 2021

AbstractThe European grapevine moth, Lobesia botrana (Denis et Schiffermuller), is a serious invasive pest that causes significant losses to the flowers and fruits of grapes in most of the world. This multivoltine pest passes the winter as the third-generation diapausing pupa. The current study was designed to compare nondiapausing (first and second generations) and diapausing pupae (third generation) and to investigate the relationship among cold tolerance, the supercooling point (SCP), and diapause development of the third-generation diapausing pupae. The lethal temperatures (LTs) for the three generations were determined using 24-h exposure at subzero temperatures. The mean SCP of the pupae was estimated at approx. −22.6°C, the lowest level of which (−23.7°C) was recorded in the well-developed diapausing pupae in February. The highest level of cold tolerance was also recorded in February. There were no significant differences among the temperatures required to kill 30, 50, and 90% of the pupae. The temperatures significantly decreased from October onward and reached the lowest levels in February during which the lowest SCP and the highest cold tolerance were observed in the diapausing pupae. No significant differences were found in the cryoprotectant levels, among the diapausing and nondiapausing pupae, and the diapause development. The highest activity of cAMP-dependent protein kinase (AMPK) was recorded in the late diapause in February. The findings suggested a relationship among SCP depression, cold tolerance enhancement, and diapause development. A bimodal cold-tolerance strategy (freeze-intolerant and freeze-tolerant) was found to be a feature of the pupae.
UGT76B1, a promiscuous hub of small molecule-based immune signaling, glucosylates N-hydroxypipecolic acid, and balances plant immunity
Authors: Bauer Sibylle , Mekonnen Dereje W , Hartmann Michael , Yildiz Ipek , Janowski Robert , Lange Birgit , Geist Birgit , Zeier Jürgen , Schäffner Anton R 
Published: January 2021

AbstractGlucosylation modulates the biological activity of small molecules and frequently leads to their inactivation. The Arabidopsis thaliana glucosyltransferase UGT76B1 is involved in conjugating the stress hormone salicylic acid (SA) as well as isoleucic acid (ILA). Here, we show that UGT76B1 also glucosylates N-hydroxypipecolic acid (NHP), which is synthesized by FLAVIN-DEPENDENT MONOOXYGENASE 1 (FMO1) and activates systemic acquired resistance (SAR). Upon pathogen attack, Arabidopsis leaves generate two distinct NHP hexose conjugates, NHP-O-β-glucoside and NHP glucose ester, whereupon only NHP-O-β-glucoside formation requires a functional SA pathway. The ugt76b1 mutants specifically fail to generate the NHP-O-β-glucoside, and recombinant UGT76B1 synthesizes NHP-O-β-glucoside in vitro in competition with SA and ILA. The loss of UGT76B1 elevates the endogenous levels of NHP, SA, and ILA and establishes a constitutive SAR-like immune status. Introgression of the fmo1 mutant lacking NHP biosynthesis into the ugt76b1 background abolishes this SAR-like resistance. Moreover, overexpression of UGT76B1 in Arabidopsis shifts the NHP and SA pools toward O-β-glucoside formation and abrogates pathogen-induced SAR. Our results further indicate that NHP-triggered immunity is SA-dependent and relies on UGT76B1 as a common metabolic hub. Thereby, UGT76B1-mediated glucosylation controls the levels of active NHP, SA, and ILA in concert to balance the plant immune status.
Neuromodulatory Effect of Transcranial Direct Current Stimulation on Resting-State EEG Activity in Internet Gaming Disorder: A Randomized, Double-Blind, Sham-Controlled Parallel Group Trial
Authors: Lee Ji-Yoon , Jang Joon Hwan , Choi A Ruem , Chung Sun Ju , Kim Bomi , Park Minkyung , Oh Sohee , Jung Myung Hun , Choi Jung-Seok 
Published: January 2021

Abstract
Transcranial direct current stimulation (tDCS) has been used as an adjunct therapy for psychiatric disorders; however, little is known about the underlying neurophysiological effects of tDCS in Internet gaming disorder (IGD). We investigated the effects of tDCS on cortical activity using resting-state electroencephalography (EEG) in patients with IGD. This randomized, double-blind, sham-controlled parallel group study of tDCS (ClinicalTrials.gov NCT03347643) included 31 IGD patients. Participants received 10 sessions (2 sessions per day for 5 consecutive days) of active repetitive tDCS (2 mA for 20 min per session) or sham stimulation. Anode/cathode electrodes were placed over the left and right dorsolateral prefrontal cortex, respectively. In total, 26 participants (active group n = 14; sham group n = 12) completed the trial. Resting-state EEG spectral activity (absolute power) and functional connectivity (coherence) were used to assess the effects of tDCS on cortical activity before stimulation and 1 month after the intervention. Active stimulation of tDCS suppressed increase of intra-hemispheric beta coherence after 1 month, which was observed in the sham group. The 1-month follow-up assessment revealed that absolute gamma power in the left parietal region was decreased in the active group relative to the sham group. Our findings suggest that repetitive tDCS stabilizes fast-wave activity in IGD.