bluuebunny/crossref_metadata_2025 huggingface dataset:
Control of Meiotic Drive of B Chromosomes in the Mealybug, Pseudococcus affinis (obscurus)
Authors: Nur Uzi , Brett Betty Lou H
Published: January 2021

Isofemale lines of Pseudococcus affinis (Maskell) differ in their ability to maintain B chromosomes (Bs) due to the presence of genotypes that affect the rate of transmission (k) of the Bs. The nature of these genotypes was analyzed by comparing ks of males carrying the same B and the same paternal genome (which is heterochromatic), but differing in their maternal genome. In males from line L-60, which maintained the B at a frequency of over 4.0 Bs per individual, the mean k varied between 0.7 and 0.95 in different experiments. Over the same period, the mean k of males with a maternal genome from one of two lines in which the B was rapidly lost (L-119), increased from 0.5 to 0.9, and that of the other line (L-230) decreased gradually from 0.6 to less than 0.1. The ks appear not to be correlated with the geographical or parental origin of the B. The observed changes in k are attributed at least in part to changes in the frequency of genotypes (alleles) which can drastically reduce the transmission of the B and, when present in high frequency, can lead to its rapid loss. The frequency distribution of the ks of sons of F1 females from the cross L-230 x L-60 suggests that the two lines differ at two unlinked loci with additive effects on k. The genome of L-119 also caused the B to undergo nondisjunction in about 10% of the primary spermatocytes. A comparison between the ks of the males tested and those of males from a natural population suggests that in that population the B is "parasitic" and that the frequency of transmission-reducing genotypes is low.
Recalibration of the Pseudomonas aeruginosa Strain PAO Chromosome Map in Time Units Using High-Frequency-of-Recombination Donors
Authors: O'Hoy Kim , Krishnapillai Viji
Published: January 2021

High-frequency-of-recombination donors of P. aeruginosa strain PAO were generated using a temperature-sensitive, replication mutant of the IncP-1 plasmid R68, loaded with the transposon Tn2521. Fourteen donors so isolated mobilized the chromosome in a polarized manner from a number of different transfer origins. The donors were used to construct a time of entry map of the entire chromosome and this was achieved by determining the time of entry of 32 randomly dispersed markers in crosses using nalidixic acid to interrupt chromosome transfer. Analysis of the time of entry data enabled the recalibration of the chromosome map to 75 min.
Temperature-Sensitive Lethal Pseudorevertants of ste Mutations in Saccharomyces cerevisiae
Authors: Katz Margaret E , Ferguson Jill , Reed Steven I
Published: January 2021

A procedure was devised to isolate mutations that could restore conjugational competence to temperature sensitive ste mutants and simultaneously confer temperature-sensitive lethal growth phenotypes. Three such mutations, falling into two complementation groups, were identified on the basis of suppression of ste5 alleles. These same mutations were later shown to be capable of suppressing ste4 and ste7 alleles. Five mutations in a single complementation group were isolated as suppressors of ste2 alleles. None of the mutations described in this study conferred a homogeneous cell cycle arrest phenotype, and all were shown to define complementation groups distinct from those previously identified in studies of cell division cycle (cdc) mutations. In no instance did pseudoreversion appear to be achieved by mutational G1 arrest of ste mutant cells. Instead, it is proposed that the mutations restore conjugation by reestablishing the normal pheromone response.
Three Genes Are Required for trans-Activation of Ty Transcription in Yeast
Authors: Winston Fred , Dollard Catherine , Malone Elizabeth A , Clare Jeffrey , Kapakos James G , Farabaugh Philip , Minehart Patricia L
Published: January 2021

Mutations in the SPT3 gene were isolated as one class of suppressors of Ty and solo δ insertion mutations in Saccharomyces cerevisiae. Previous work has shown that null mutations in SPT3 abolish the normal Ty δ-δ transcript; instead, a transcript that initiates 800 bases farther downstream is made, suggesting that SPT3 is required for transcription initiation in δ sequences. We have selected for new spt mutations and have screened for those with the unique suppression pattern of spt3 mutations with respect to two insertion mutations. Our selection and screen has identified two additional genes, SPT7 and SPT8, that are also required for transcription initiation in δ sequences. We show that mutations in SPT7 or SPT8 result in the same alteration of Ty transcription as do mutations in SPT3. In addition, mutations in all three genes cause a sporulation defect. By assay of a Ty-lacZ fusion we have shown that spt3, spt7 and spt8 mutations reduce transcription from a δ sequence by 10-25-fold. Finally, we show that SPT3 mRNA levels are unaffected in either spt7 or spt8 mutants, suggesting that these two genes do not regulate transcription of SPT3.
The Constitutive, Glucose-Repression-Insensitive Mutation of the Yeast MAL4 Locus Is an Alteration of the MAL43 Gene
Authors: Charron Maureen J , Michels Corinne A
Published: January 2021

Mutations resulting in constitutive production of maltase have been identified at each of the five MAL loci of Saccharomyces yeasts. Here we examine a dominant constitutive, glucose-repression-insensitive allele of the MAL4 locus (MAL4-C). Our results demonstrate that MAL4-C is an alteration in the MAL43 gene, which encodes the positive regulator of the MAL structural genes, and that its product is trans-acting. The MAL43 gene from the MAL4-C strain was cloned and integrated into a series of nonfermenting strains lacking a functional regulatory gene but carrying copies of the maltose permease and maltase structural genes. Expression of the maltase structural gene was both constitutive and insensitive to glucose repression in these transformants. The MAL4-C allele also results in constitutive expression of the unlinked MAL12 gene (encoding maltase) in this strain. In addition, the cloned MAL43 gene was shown to be dominant to the wild-type MAL63 gene. We also show that most of the glucose repression insensitivity of strains carrying the MAL4-C allele results from alteration of MAL43.
X-4 Translocations and Meiotic Drive in Drosophila melanogaster Males: Role of Sex Chromosome Pairing
Authors: McKee Bruce
Published: January 2021

Males carrying certain X-4 translocations exhibit strongly skewed sperm recovery ratios. The XP4D half of the translocation disjoins regularly from the Y chromosome and the 4PXD half disjoins regularly from the normal 4. Yet the smaller member of each bivalent is recovered in excess of its pairing partner, apparently due to differential gametic lethality. Chromosome recovery probabilities are multiplicative; the viability of each genotype is the product of the recovery probability of its component chromosomes. Meiotic drive can also be caused by deficiency for X heterochromatin. In(1)sc4Lsc8R males show the same size dependent chromosome recoveries and multiplicative recovery probabilities found in T(1;4)BS males. Meiotic drive in In(1)sc4Lsc8R males has been shown to be due to X-Y pairing failure. Although pairing is regular in the T(X;4) males, the striking phenotypic parallels suggest a common explanation. The experiments described below show that the two phenomena are, in fact, one and the same. X-4 translocations are shown to have the same effect on recovery of independently assorting chromosomes as does In(1)sc4Lsc8R. Addition of pairing sites to the 4PXD half of the translocation eliminates drive. A common explanation—failure of the distal euchromatic portion of the X chromosome to participate in X:Y meiotic pairing—is suggested as the cause for drive. The effect of X chromosome breakpoint on X-4 translocation induced meiotic drive is investigated. It is found that translocations with breakpoints distal to 13C on the salivary map do not cause drive while translocations broken proximal to 13C cause drive. The level of drive is related to the position of the breakpoint—the more proximal the breakpoint the greater the drive.
enhancer of seizure: A New Genetic Locus in Drosophila melanogaster Defined by Interactions With Temperature-Sensitive Paralytic Mutations
Authors: Kasbekar Durgadas P , Nelson James C , Hall Linda M
Published: January 2021

Mutations in the enhancer of seizure (e(sei)) locus have been isolated on the basis of their ability to cause temperature-induced paralysis of alleles at the seizure (sei) locus at temperatures at which these mutations ordinarily do not paralyze. This enhancer is specific to the seizure locus and is without effect on other temperature-sensitive paralytic mutants including para, nap, tip-E and shi. This suggests that the enhancer responds specifically to the mechanism of paralysis mediated by the seizure mutations. The e(sei) is a recessive mutation which maps to 39.0 on the left arm of chromosome 3. Deficiency mapping has placed it at 69A4-B5 on the salivary gland polytene chromosome map. When a new enhancer allele was isolated following P-M hybrid dysgenesis, there was a concomitant P-element insertion at 69B. In the absence of seizure mutations, the enhancer mutation causes non-temperature dependent hyperactivity when agitated and interferes with the climbing response. Electrophysiological studies examined the effects of increasing temperature on electrical activity in the adult giant fiber/flight muscle system. Neuronal hyperactivity was seen in both e(sei) and sei single mutant homozygotes, but not in wild type. The hyperactivity was more severe in the sei;e(sei) double mutants. The correlation between the physiological effects and the mutant behavior suggests that both sei and e(sei) cause membrane excitability defects. Since previous work has shown that seizure mutants affect [3H]saxitoxin binding to the voltage-sensitive sodium channel, e(sei) may code for a gene product which interacts with this channel.
Genetic Analysis of Delta, a Neurogenic Gene of Drosophila melanogaster
Authors: Vässin Harald , Campos-Ortega Jose A
Published: January 2021

We report here the results of a genetic analysis of the gene Delta (Dl) of Drosophila melanogaster. Dl has been mapped to the band 92A2, on the basis of two pieces of evidence: (1) this band is the common breakpoint of several chromosomal aberrations associated with Dl mutations and (2) recombination mapping of alleles of five different lethal complementation groups that are uncovered by Df(3R)DlFX3 (breakpoints at 91F11; 92A3). Dl was found to map most distally of all five complementation groups. The analysis of a large number of Dl alleles demonstrates the considerable genetic and functional complexity of Dl. Three types of Dl alleles are distinguishable. Most alleles behave as amorphic or hypomorphic recessive embryonic lethal alleles, which in addition cause various defects in heterozygosity over the wild-type allele. The defects are due to haplo-insufficient expression of the locus and can be suppressed by a duplication of the wild-type allele. The second class is comprised of three alleles with antimorphic expression. The phenotype of these alleles can only be reduced, rather than suppressed, by a duplication of the wild-type allele. The third group is comprised of three visible, predominantly hypomorphic alleles with an antimorphic component of phenotypic expression. The pattern of interallelic complementation is complex. On the one hand, there is a group of hypomorphic, fully penetrant embryonic lethal alleles which complement each other. On the other hand, most alleles, including all amorphic alleles, are viable over the visible ones; alleles of antimorphic expression, however, are lethal over visible alleles. These results are compatible with a rather complex genetic organization of the Dl locus.
Identification of Sites Influencing the Folding and Subunit Assembly of the P22 Tailspike Polypeptide Chain Using Nonsense Mutations
Authors: Fane Bentley , King Jonathan
Published: January 2021

Amber mutations have been isolated and mapped to more than 60 sites in gene 9 of P22 encoding the thermostable phage tailspike protein. Gene 9 is the locus of over 30 sites of temperature sensitive folding (tsf) mutations, which affect intermediates in the chain folding and subunit association pathway. The phenotypes of the amber missense proteins produced on tRNA suppressor hosts inserting serine, glutamine, tryosine and leucine have been determined at different temperatures. Thirty-three of the sites are tolerant, producing functional proteins with any of the four amino acids inserted at the sites, independent of temperature. Tolerant sites are concentrated at the N-terminal end of the protein indicating that this region is not critical for conformation or function. Sixteen of the sites yield temperature sensitive missense proteins on at least one nonsense suppressing host. Most of the sites with ts phenotypes map to the central region of the gene which is also the region where most of the tsf mutations map. Mutations at 15 of the sites have a lethal phenotype on at least one tRNA suppressor host. For nine out of ten sites tested with at least one lethal phenotype, the primary defect was in the folding or subunit association of the missense polypeptide chain. This analysis of the tailspike missense proteins distinguishes three classes of amino acid sites in the polypeptide chain; residues whose side chains contribute little to folding, subunit assembly or function; residues critical for maintaining the folding and subunit assembly pathway at the high end of the temperature range of phage growth; and residues critical over the entire temperature range of growth.
Extended Region of Nodulation Genes in Rhizobium meliloti 1021. II. Nucleotide Sequence, Transcription Start Sites and Protein Products
Authors: Fisher Robert F , Swanson Jean A , Mulligan John T , Long Sharon R
Published: January 2021

We have established the DNA sequence and analyzed the transcription and translation products of a series of putative nodulation (nod) genes in Rhizobium meliloti strain 1021. Four loci have been designated nodF, nodE, nodG and nodH. The correlation of transposon insertion positions with phenotypes and open reading frames was confirmed by sequencing the insertion junctions of the transposons. The protein products of these nod genes were visualized by in vitro expression of cloned DNA segments in a R. meliloti transcription-translation system. In addition, the sequence for nodG was substantiated by creating translational fusions in all three reading frames at several points in the sequence; the resulting fusions were expressed in vitro in both E. coli and R. meliloti transcription-translation systems. A DNA segment bearing several open reading frames downstream of nodG corresponds to the putative nod gene mutated in strain nod-216. The transcription start sites of nodF and nodH were mapped by primer extension of RNA from cells induced with the plant flavone, luteolin. Initiation of transcription occurs approximately 25 bp downstream from the conserved sequence designated the "nod box," suggesting that this conserved sequence acts as an upstream regulator of inducible nod gene expression. Its distance from the transcription start site is more suggestive of an activator binding site rather than an RNA polymerase binding site.
Some Features of Base Pair Mismatch and Heterology Repair in Escherichia coli
Authors: Raposa Susan , Fox Maurice S
Published: January 2021

We have used artificially constructed heteroallelic heteroduplex molecules of bacteriophage lambda DNA to transfect Escherichia coli, and E. coli mutants deficient in various functions involved in the adenine methylation-directed mismatch repair system, MutL, MutS, MutH, and UvrD (MutU). Analysis of the allele content of single infective centers shows that this repair system often acts on several mismatches, separated by as many as 2000 bp, on one of the strands of a heteroduplex molecule. When the methyl-directed mismatch repair system is disabled by mutH or uvrD mutations, localized mismatch repair becomes prominent. This prominent localized repair that can result in separation of very closely linked markers requires the functions MutL and MutS, is independent of adenine methylation, and appears to reflect another mechanism of mismatch repair. Heterology-containing heteroduplex molecules with a deletion in one strand often escape processing. However, when the heterology includes the stem and loop structure of a transposon, Tn10, the transposon is lost.
Selective Recombination System in Bombyx mori. I. Chromosome Specificity of the Modification Effect
Authors: Ebinuma Hiroyasu
Published: January 2021

The effect of modifiers on recombination frequency between Ze and lem loci on chromosome 3 to elucidate the chromosome specificity of modification and the distribution of modifiers using Bombyx mori lines selected for high (H) and low (L) recombination rates between the pS and Y loci in chromosome 2 was investigated. By crossing to the Z (Ze lem/++) line, the recombination rate between the pS and Y loci in chromosome 2 was decreased from 28.18 to 23.33 in the H line and was increased from 4.92 to 16.05 in the L line. On the other hand, the recombination rate between the Ze and lem loci in chromosome 3 was increased from 16.21 to 20.21 in the Z line by crossing to the H line, but also increased to 19.02 by crossing to the L line. The significant correlation observed between the transformed recombination rates of chromosomes 2 and 3 in the (Z × L) × L backcross indicated that there were common factors modifying recombination frequency in chromosomes 2 and 3 or different factors linked to the same chromosomes. In the family of L × [(Z × L) × L] backcross, the distribution of transformed recombination rates indicated that there were several factors in the remaining chromosomes which were modifying recombination frequency in chromosome 2 but not in chromosome 3. It was also indicated that these factors were linked to different chromosomes than are the factors modifying recombination frequency in chromosome 3. In order to interpret these results, one genetic system model controlling recombination that consists of general and local recombination modifiers was proposed. The evolution of dynamic genetic systems that would effectively reduce recombinational load without reducing the advantage of recombination was discussed.
Somatic Effects of P Element Activity in Drosophila melanogaster: Pupal Lethality
Authors: Engels William R , Benz Wendy K , Preston Christine R , Graham Patricia L , Phillis Randall W , Robertson Hugh M
Published: January 2021

Nonautonomous P elements normally excise and transpose only when a source of transposase is supplied, and only in the germline. The germline specificity depends on one of the introns of the transposase gene which is not spliced in somatic cells. To study the effects of somatic P activity, a modified P element (Δ2-3) lacking this intron was used as a source of transposase. Nonautonomous P elements from a strain called Birmingham, when mobilized in somatic cells by Δ2-3, were found to cause lethality, although neither component was lethal by itself. The three major Birmingham chromosomes acted approximately independently in producing the lethal effect. This lethality showed a strong dependence on temperature. Although temperature sensitivity was limited to larval stages, the actual deaths occurred at the pupal stage. Survivors, which could be recovered by decreasing the temperature or by reducing the proportion of the Birmingham genome present, often showed multiple developmental anomalies and reduced longevity reminiscent of the effects of cell death from radiation damage. Although the genetic damage occurred in dividing imaginal disc cells, the phenotypic manifestations—death and abnormalities—are not observed until later. The survivors also showed gonadal dysgenic (GD) sterility, a well-known characteristic of P-M hybrid dysgenesis. To explain these findings, we suggest that pupal lethality and GD sterility are both caused by massive chromosome breakage in larval cells, resulting from excision and transposition of genomic P elements acting as substrate for the transposase.
The differential contribution by individual enzymes of glycolysis and protein catabolism to the relationship between heterozygosity and growth rate in the coot clam, Mulinia lateralis.
Authors: Koehn R K , Diehl W J , Scott T M
Published: January 2021

The locus-specific effects of heterozygosity upon individual growth rate were determined for 15 polymorphic enzymes among 1906 individuals from a single cohort sample of the marine bivalve Mulinia lateralis. Two measures of individual growth rate (total wet weight and shell length) were made at collection and after a period of growth in the laboratory. The correlation between heterozygosity and growth rate was independently determined for each locus using multiple linear regression, thereby providing a rank of individual locus effects; these differed significantly. The four estimated rankings of relative locus effects (initial length, initial weight, length added in the laboratory, and added weight) were not statistically different. That is, a locus with a large effect of heterozygosity on growth rate in nature had a similarly large effect on laboratory growth rate. The effect of a locus was not related to heterozygosity per se; some highly heterozygous loci had no detectable correlation with growth rate. The data contained two pairs of relatively tightly linked loci; in both cases one locus of a pair had significant effects on growth rate, while the other had no effect. Loci with large and significant correlations with growth rate synthesize enzymes which function in protein catabolism or glycolysis; heterozygosity in enzymes of the pentose shunt, redox balance, or other miscellaneous metabolic roles was not correlated with growth rate. Since the metabolic basis for the correlation is known to derive from individual differences in net energy status, particularly energetic costs of whole-body protein turnover, these data indicate that phenotypic effects (e.g., variation in growth rate) are determined by heterozygosity at the studied genes, not other linked loci.
DNA sequence determinants of lambda repressor binding in vivo.
Authors: Benson N , Sugiono P , Youderian P
Published: January 2021

The critical operator determinants for lambda repressor recognition have been defined by analyzing the binding of wild-type repressor to a set of mutant operators in vivo. Base pair substitutions at six positions within the lambda operator half-site impair binding severely, and define these base pairs as critical for operator function. One mutant operator binds repressor better than the consensus operator, and is a superoperator. The model proposed by M. Lewis in 1983 for the binding of lambda repressor to its operator accurately predicts the observed operator requirements for binding in vivo, with several minor exceptions. The order of affinities of the six natural lambda operators has also been determined.
Mapping of Escherichia coli chromosomal Tn5 and F insertions by pulsed field gel electrophoresis.
Authors: Smith C L , Kolodner R D
Published: January 2021

A low resolution Not I physical map of Escherichia coli was recently constructed. In this report we demonstrated that this map can be used to map Tn5 and F insertions physically. The transposon, Tn5, contains Not I recognition sequences in its IS50 sequences. F plasmid contains an unmapped Not I site. Hence, the location of Tn5 and F in the chromosome can be mapped by identifying the location of the introduced Not I sites using pulsed field gel electrophoresis. The physical mapping of genetically mapped Tn5 insertions confirm the previously constructed Not I map and helps align the E. coli physical and genetic maps. The use of Tn5 can assist the construction of both physical and genetic maps for microorganisms lacking such maps. Variations on this approach will facilitate physical mapping with a wide variety of organisms, enzymes, and genetic elements.
Meiotic disjunction of homologs in Saccharomyces cerevisiae is directed by pairing and recombination of the chromosome arms but not by pairing of the centromeres.
Authors: Surosky R T , Tye B K
Published: January 2021

We explored the behavior of meiotic chromosomes in Saccharomyces cerevisiae by examining the effects of chromosomal rearrangements on the pattern of disjunction and recombination of chromosome III during meiosis. The segregation of deletion chromosomes lacking part or all (telocentric) of one arm was analyzed in the presence of one or two copies of a normal chromosome III. In strains containing one normal and any one deletion chromosome, the two chromosomes disjoined in most meioses. In strains with one normal chromosome and both a left and right arm telocentric chromosome, the two telocentrics preferentially disjoined from the normal chromosome. Homology on one arm was sufficient to direct chromosome disjunction, and two chromosomes could be directed to disjoin from a third. In strains containing one deletion chromosome and two normal chromosomes, the two normal chromosomes preferentially disjoined, but in 4-7% of the tetrads the normal chromosomes cosegregated, disjoining from the deletion chromosome. Recombination between the two normal chromosomes or between the deletion chromosome and a normal chromosome increased the probability that these chromosomes would disjoin, although cosegregation of recombinants was observed. Finally, we observed that a derivative of chromosome III in which the centromeric region was deleted and CEN5 was integrated at another site on the chromosome disjoined from a normal chromosome III with fidelity. These studies demonstrate that it is not pairing of the centromeres, but pairing and recombination along the arms of the homologs, that directs meiotic chromosome segregation.
Hybrid DNA extension and reciprocal exchanges: alternative issues of an early intermediate during meiotic recombination?
Authors: Langin T , Haedens V , Rossignol J L
Published: January 2021

Large heterologies in gene b2 strongly increase the frequencies of reciprocal exchanges on their left border, towards the high conversion end. In a previous study, we observed that heterozygous point mutations located in the high conversion end (region F) stimulate the reciprocal exchanges instigated by the large heterology 138. We have defined some properties of this stimulation. The effect does not depend on the nature of the large heterology used. It is effective only with point mutations located on the left side of the large heterology. It does not depend on the number of heterozygosities accumulated in region F. It is not specific on the location of point mutations in region F: it decreases from region F (left end) to region E (middle part of b2). It is correlated with the mismatch correction efficiencies of the point mutations used. It is not observed in the absence of a large heterology. Point mutation heterozygosities which stimulate reciprocal exchanges also decrease the frequency of HDNA formation in gene b2. We propose a model in which reciprocal exchanges on the one hand and hybrid DNA formation on the other hand correspond to alternative processings of a common recombination intermediate.
Spontaneous Activation of Quiescent Uq Transposable Elements during Endosperm Development in Zea Mays.
Authors: Pan Y B , Peterson P A
Published: January 2021

This study addresses the question of the activation of quiescent transposable elements in maize breeding lines. The a-ruq reporter allele of the Uq transposable element system expresses Uq activity (spots or sectors of spots in otherwise colorless aleurone tissue) when exposed to various genotypes of assorted maize inbred lines lacking any active Uq element. This activation of quiescent Uq elements occurs randomly during the growth of the endosperm. It is concluded that there are components in the genome that enhance the rare activation of quiescent Uq elements. Further, it seems that this activation occurs in the absence of any stress-inducing treatment, but that normal growth conditions provide sufficient stimulus for such activation.
Domains for protein-protein interactions at the N and C termini of the large subunit of bacteriophage lambda terminase.
Authors: Wu W F , Christiansen S , Feiss M
Published: January 2021

The large subunit of phage lambda terminase, gpA, the gene product of the phage A gene, interacts with the small subunit, gpNul, to form functional terminase. Terminase binds to lambda DNA at cosB to form a binary complex. The terminase:DNA complex binds a prohead to form a ternary complex. Ternary complex formation involves an interaction of the prohead with gpA. The amino terminus of gpA contains a functional domain for interaction with gpNul, and the carboxy-terminal 38 amino acids of gpA contain a functional domain for prohead binding. This information about the structure of gpA was obtained through the use of hybrid phages resulting from recombination between lambda and the related phage 21. lambda and 21 encode terminases that are analogous in structural organization and have ca. 60% sequence identity. In spite of these similarities, lambda and 21 terminases differ in specificity for DNA binding, subunit assembly, and prohead binding. A lambda-21 hybrid phage produces a terminase in which one of the subunits is chimeric and had recombinant specificities. In the work reported here; a new hybrid, lambda-21 hybrid 67, is characterized. lambda-21 hybrid 67 is the result of a crossover between lambda and 21 in the large subunit genes, such that the DNA from the left chromosome end is from 21, including cosB phi 21, the 1 gene, and the first 48 codons for the 2 gene. The rest of the hybrid 67 chromosome is lambda DNA, including 593 codons of the A gene. The chimeric gp2/A of hybrid 67 binds gp1 to form functional terminase.(ABSTRACT TRUNCATED AT 250 WORDS)
Characterization of the AdhSL regulatory mutation in Drosophila melanogaster.
Authors: Schott D R , East P D , Paigen K
Published: January 2021

We describe the characterization of a previously reported control mutation, AdhSL, in the alcohol dehydrogenase gene of Drosophila melanogaster, which results in decreased production of ADH molecules and subsequently lower ADH activity in adults. We find that the regulatory element modifies ADH mRNA levels and acts cis on both ADH protein and mRNA. It is not promoter specific but is developmentally specific to the adult stage. The AdhSL allele carries a 4.5-kb insert approximately 3 kb 5' to the distal promoter. This new insertion may be responsible for the regulatory phenotype of AdhSL.
Pseudo-random mating populations. In celebration of the 80th anniversary of the Hardy-Weinberg law.
Authors: Li C C
Published: January 2021

That random mating leads to Hardy-Weinberg distribution of genotypes is well known. This report is to show that, if the deviations from random mating are of a certain pattern, the offspring generation will also be in Hardy-Weinberg proportions. This brings out the fact that random mating is a sufficient condition, not a necessary one, for the attainment of the Hardy-Weinberg proportions. Such nonrandom-mating populations are tentatively said to be pseudo-random mating. Pseudo-random-mating populations exist for both autosomal and sex-linked systems with two or multiple alleles. This report covers the basic case of a two-allele autosomal locus in detail, but the possible extension to two loci and cytonuclear systems have also been mentioned in discussion.
Linkage disequilibrium in human ribosomal genes: implications for multigene family evolution.
Authors: Seperack P , Slatkin M , Arnheim N
Published: January 2021

Members of the rDNA multigene family within a species do not evolve independently, rather, they evolve together in a concerted fashion. Between species, however, each multigene family does evolve independently indicating that mechanisms exist which will amplify and fix new mutations both within populations and within species. In order to evaluate the possible mechanisms by which mutation, amplification and fixation occur we have determined the level of linkage disequilibrium between two polymorphic sites in human ribosomal genes in five racial groups and among individuals within two of these groups. The marked linkage disequilibrium we observe within individuals suggests that sister chromatid exchanges are much more important than homologous or nonhomologous recombination events in the concerted evolution of the rDNA family and further that recent models of molecular drive may not apply to the evolution of the rDNA multigene family.
Genetic divergence in mandible form in relation to molecular divergence in inbred mouse strains.
Authors: Atchley W R , Newman S , Cowley D E
Published: January 2021

Genetic divergence in the form of the mandible is examined in ten inbred strains of mice. Several univariate and multivariate genetic distance estimates are given for the morphological data and these estimates are compared to measures of genealogical and molecular divergence. Highly significant divergence occurs among the ten strains in all 11 mandible traits considered individually and simultaneously. Genealogical relationship among strains is highly correlated with genetic divergence in single locus molecular traits. However, the concordance between genealogical relationship and multivariate genetic divergence in morphology is much more complex. Whether there is a significant correlation between morphological divergence and genealogy depends upon the method of analysis and the particular genetic distance statistic being employed.
On the theory of partially inbreeding finite populations. II. Partial sib mating.
Authors: Pollak E
Published: January 2021

It is assumed that a population has M males in every generation, each of which is permanently mated with c-1 females, and that a proportion beta of matings are between males and their full sisters or half-sisters. Recurrence equations are derived for the inbreeding coefficient of one random individual, coefficients of kinship of random pairs of mates and probabilities of allelic identity when the infinite alleles model holds. If Ft is the inbreeding coefficient at time t and M is large, (1-Ft)/(1-Ft-1)----1-1/(2Ne) as t increases. The effective population number Ne = aM/[1 + (2a-1)FIS], where FIS is the inbreeding coefficient at equilibrium when M is infinite and the constant a depends upon the conditional probabilities of matings between full sibs and the two possible types of half-sibs. When there are M permanent couples, an approximation to the probability that an allele A survives if it is originally present in one AA heterozygote is proportional to FISs1 + (1-FIS)s2, where s1 and s2 are the selective advantages of AA and AA in comparison with AA. The paper concludes with a comparison between the results when there is partial selfing, partial full sib mating (c = 2) and partial sib mating when c is large.
Molecular structure and transformation of the glucose dehydrogenase gene in Drosophila melanogaster.
Authors: Whetten R , Organ E , Krasney P , Cox-Foster D , Cavener D
Published: January 2021

We have precisely mapped and sequenced the three 5' exons of the Drosophila melanogaster Gld gene and have identified the start sites for transcription and translation. The first exon is composed of 335 nucleotides and does not contain any putative translation start codons. The second exon is separated from the first exon by 8 kb and contains the Gld translation start codon. The inferred amino acid sequence of the amino terminus contains two unusual features: three tandem repeats of serine-alanine, and a relatively high density of cysteine residues. P element-mediated transformation experiments demonstrated that a 17.5-kb genomic fragment contains the functional and regulatory components of the Gld gene.
Investigating the interaction of terbinafine with xanthenes dye for its feasible determination applying the resonance Rayleigh scattering technique
Authors: Abdel-Lateef Mohamed A. , Derayea Sayed M. , El-Deen Deena A. M. Nour , Almahri Albandary , Oraby Mohamed
Published: January 2021

Terbinafine hydrochloride is a potent antifungal drug indicated for oral and topical treatment of mycoses. A resonance Rayleigh scattering (RRS) method was developed for the determination of terbinafine hydrochloride through a feasible complexation reaction with erythrosine B. In a weakly acidic medium (acetate buffer, pH 5.0), terbinafine hydrochloride can react with erythrosine B through the electrostatic attraction and virtue of hydrophobic force to form an ion-association complex. The reaction resulted in the appearance of a new RRS peak at 369 nm. The RRS peak was increased by increasing the concentration of terbinafine hydrochloride in the linear range of 0.1–1.5 µg ml
−1
. All the reaction conditions (erythrosine B concentration, buffer volume, diluting solvent and pH) were optimized. The detection limit was 0.029 µg ml
−1
while the quantitation limit was 0.089 µg ml
−1
. The suggested method after its validation was successfully applied for the determination of terbinafine hydrochloride in different pharmaceutical formulations (tablets and cream) with sufficient recovery.
Capturing the complexity of topologically associating domains through multi-feature optimization
Authors: Sauerwald Natalie , Kingsford Carl
Published: January 2021

The three-dimensional structure of human chromosomes is tied to gene regulation and replication timing, but there is still a lack of consensus on the computational and biological definitions for chromosomal substructures such as topologically associating domains (TADs). TADs are described and identified by various computational properties leading to different TAD sets with varying compatibility with biological properties such as boundary occupancy of structural proteins. We unify many of these computational and biological targets into one algorithmic framework that jointly maximizes several computational TAD definitions and optimizes TAD selection for a quantifiable biological property. Using this framework, we explore the variability of TAD sets optimized for six different desirable properties of TAD sets: high occupancy of CTCF, RAD21, and H3K36me3 at boundaries, reproducibility between replicates, high intra- vs inter-TAD difference in contact frequencies, and many CTCF binding sites at boundaries. The compatibility of these biological targets varies by cell type, and our results suggest that these properties are better reflected as subpopulations or families of TADs rather than a singular TAD set fitting all TAD definitions and properties. We explore the properties that produce similar TAD sets (reproducibility and inter- vs intra-TAD difference, for example) and those that lead to very different TADs (such as CTCF binding sites and inter- vs intra-TAD contact frequency difference).
Disorder is a critical component of lipoprotein sorting in Gram-negative bacteria
Authors: El Rayes Jessica , Szewczyk Joanna , Deghelt Michael , Matagne André , Iorga Bogdan I. , Cho Seung-Hyun , Collet Jean-François
Published: January 2021

Gram-negative bacteria express structurally diverse lipoproteins in their envelope. Here we found that approximately half of lipoproteins destined to theEscherichia coliouter membrane display an intrinsically disordered linker at their N-terminus. Intrinsically disordered regions are common in proteins, but establishing their importancein vivohas remained challenging. Here, as we sought to unravel how lipoproteins mature, we discovered that unstructured linkers are required for optimal trafficking by the Lol lipoprotein sorting system: linker deletion re-routes three unrelated lipoproteins to the inner membrane. Focusing on the stress sensor RcsF, we found that replacing the linker with an artificial peptide restored normal outer membrane targeting only when the peptide was of similar length and disordered. Overall, this study reveals the role played by intrinsic disorder in lipoprotein sorting, providing mechanistic insight into the biogenesis of these proteins and suggesting that evolution can select for intrinsic disorder that supports protein function.
Context as knowledge
Authors: Huvenes Torfinn Thomesen , Stokke Andreas
Published: January 2021

It has been argued that common ground information is unsuited to the role that contexts play in the theory of indexical and demonstrative reference. This paper explores an alternative view that identifies shared information with what is common knowledge among the participants. We argue this view of shared information avoids the problems for the common ground approach concerning reference while preserving its advantages in accounting for communication.
Neuromyelitis optica spectrum disorder in Asia: Epidemiology and risk factors
Authors: Hor Jyh Yung , Wong Chee Keong , Ew Ju Vern , Idris Syafiq , Tan Hui Jieh , Wong Daniel Yi Jie
Published: January 2021

In Asia, prior to the discovery of aquaporin 4 (AQP4) antibody, many cases of neuromyelitis optica spectrum disorder (NMOSD) were misdiagnosed as multiple sclerosis (MS) or the so‐called opticospinal multiple sclerosis (OSMS). The AQP4 antibody discovery was an important milestone in the field of NMOSD, leading to correct diagnosis and reclassification of NMOSD cases, and the subsequent appropriate therapy. This is especially pertinent in Asia where the prevalence of MS is generally much lower than the Caucasian populations. East Asians have a higher NMOSD prevalence rate (~4/100 000) than Caucasians (~1‐1.5/100 000) and other Asian racial groups (Austronesians: 1.2‐1.5/100 000; South Asians: ~1/100 000; Arabs: ~1‐1.5/100 000). Myelin oligodendrocyte glycoprotein (MOG) antibody‐associated disease (MOGAD) comprises cases of AQP4‐antibody‐negative NMOSD, optic neuritis, myelitis, and certain unique phenotypes such as cases with acute disseminated encephalomyelitis (ADEM)‐like presentation, and cerebral cortical encephalitis. MOGAD appears not too uncommon among Japanese, Chinese, Sri Lankans and Indians, but data in different Asian populations and geographical locations are needed. There exist some differences in clinical features of NMOSD and MOGAD between Asians and other populations. As for risk factors, genetic studies have identified certain HLA associations with NMOSD among Asians that were different from other populations. North‐South latitudinal gradient as seen in MS was not observed in NMOSD in Japan and China. Seasonal variation and preceding infection are among some risk factors worth further investigations. Population‐based MOGAD study in Asia, and further genetic and environmental studies are useful to further inform the epidemiology and potential pathogenetic mechanism of this unique neuroinflammatory disease.
The development of past and future life stories in adolescence: Overall emotional tone, coherence and life script events
Authors: Ramsgaard Stine B. , Bohn Annette
Published: January 2021

Research has shown that identity in adolescence takes the shape of a coherent life story that integrates the past with the present self and provides meaning and purpose in the person’s life. One stable feature of narrative identity identified in adults is emotional tone. Here, the development of emotional tone in life stories was investigated across childhood and adolescence. A total of 142 adolescents aged 10 to 14 years wrote about their past weekend, their past and future life stories and generated a cultural life script. Across age groups, adolescents told past life stories that were overall mixed (both positive and negative) or moderately positive in emotional tone, and future life stories that were positive or highly positive. In relation to life story development, we replicated findings on age‐related development of life story coherence in both past and future life stories in 10–14‐year‐olds. Lastly, the study highlights the link between life story coherence and cultural life script abilities. Cultural life script typicality was linked to life story coherence for both past and future life stories and across all age groups, and a majority of events mentioned in future life stories overlapped with cultural life script events.
A new species of Geogamasus Lee (Mesostigmata: Ologamasidae), with morphological details on species of the genus

Authors: Barros Avyla R. A. , De Azevedo Emiliano B. , Silva Edmilson S. , De Moraes Gilberto J. , Castilho Raphael C.
Published: January 2021

Geogamasus lasaroi Barros, Azevedo & Castilho sp. nov. is described based on the morphology of adult females collected from soil-litter of a well preserved fragment of the natural vegetation of the Caatinga biome, in Alagoas state, northeastern Brazil. In addition, key information on the morphology of the world Geogamasus species is presented in a tabular format.
Rare earth doped CaWO4 and CaMoO4 thin films for white light emission
Authors: Kaur Puneet , Khanna Atul , Kaur Jatinder , Kumar Rinku , Chandra Ramesh
Published: January 2021

Crystalline thin films of Eu, Dy, and Er-doped CaWO4 and CaMoO4 of thicknesses 100–150 nm were synthesized by pulsed laser deposition on fused silica substrates. The atomic force and scanning electron microscopy studies confirm uniform and dense surface morphology of the samples. Tetragonal CaWO4 films show preferred growth of crystallites of (112) orientation. CaMoO4 shows texturing of crystallites of (004) orientation, while (112) crystallites are favored upon doping with rare earth ions. CaWO4 has a higher optical bandgap (5.0–5.2 eV) than CaMoO4 (3.6–4.4 eV), and both materials show blue light emission with stronger luminescence in molybdate samples. Eu doped CaWO4 and CaMoO4 produce red light emission, while Er-doped samples emit green light. The samples 1 mol.% Dy2O3–CaWO4 and 2 mol.% Eu2O3–5 mol.% Dy2O3–CaWO4 exhibit white light emission properties.
Adiponectin receptor 1 variants contribute to hypertrophic cardiomyopathy that can be reversed by rapamycin
Authors: Dhandapany Perundurai S. , Kang Soojeong , Kashyap Deepak K. , Rajagopal Raksha , Sundaresan Nagalingam R. , Singh Rajvir , Thangaraj Kumarasamy , Jayaprakash Shilpa , Manjunath Cholenahally N. , Shenthar Jayaprakash , Lebeche Djamel
Published: January 2021

Gene variants in adiponectin receptor 1 cause pathological enlarged hearts.
Heating events in the nascent solar system recorded by rare earth element isotopic fractionation in refractory inclusions
Authors: Hu J. Y. , Dauphas N. , Tissot F. L. H. , Yokochi R. , Ireland T. J. , Zhang Z. , Davis A. M. , Ciesla F. J. , Grossman L. , Charlier B. L. A. , Roskosz M. , Alp E. E. , Hu M. Y. , Zhao J.
Published: January 2021

The compositions of the first solar system solids were shaped by nonequilibrium condensation and evaporation.
Ultrabright Au@Cu
14
nanoclusters: 71.3% phosphorescence quantum yield in non-degassed solution at room temperature
Authors: Song Yongbo , Li Yingwei , Zhou Meng , Liu Xuan , Li Hao , Wang He , Shen Yuhua , Zhu Manzhou , Jin Rongchao
Published: January 2021

Single-gold-atom doping into a copper nanocluster lights up phosphorescence via triplet-state engineering.
Tb
3+
-doped fluorescent glass for biology
Authors: Okamoto Kazuki , Ebina Teppei , Fujii Naoki , Konishi Kuniaki , Sato Yu , Kashima Tetsuhiko , Nakano Risako , Hioki Hiroyuki , Takeuchi Haruki , Yumoto Junji , Matsuzaki Masanori , Ikegaya Yuji
Published: January 2021

Tb
3+
-doped glass emits GFP-like fluorescence and is versatile for various biological research purposes.
Gene expression signatures of target tissues in type 1 diabetes, lupus erythematosus, multiple sclerosis, and rheumatoid arthritis
Authors: Szymczak F. , Colli M. L. , Mamula M. J. , Evans-Molina C. , Eizirik D. L.
Published: January 2021

Target tissues of four autoimmune diseases show similar gene expression signatures emphasizing a dialog immune cell-target tissue.