bluuebunny/crossref_metadata_2025 huggingface dataset:
Fluorescence coupling to internal modes of 1D photonic crystals characterized by back focal plane imaging
Authors: Choudhury Sharmistha Dutta , Xiang Yifeng , Zhang Douguo , Descrovi Emilano , Badugu Ramachandram , Lakowicz Joseph R
Published: January 2021

The coupling of fluorescence with surface electromagnetic modes, such as surface plasmons on thin metal films or Bloch surface waves (BSWs) on truncated one-dimensional photonic crystals (1DPCs), are presently utilized for many fluorescence-based applications. In addition to the surface wave, 1DPCs also support other electromagnetic modes that are confined within the 1DPC structure. These internal modes (IMs) have not received much attention for fluorescence coupling due to lack of spatial overlap of their electric fields with the surface bound fluorophores. However, our recent studies have indicated that the fluorescence coupling with IMs occurs quite efficiently. This observed internal mode-coupled emission (IMCE) is (similar to BSW-coupled emission) indeed wavelength dependent, directional and S-polarized. In this paper, we have carried out back-focal plane imaging to reveal that the IMs of 1DPCs can couple with surface bound excited dye molecules, with or without a BSW mode presence. Depending on the emission wavelength, the coupling is observed with BSW and IMs or only IMs of the 1DPC structure. The experimental results are well matching with numerical simulations. The occurrence of IMCE regardless of the availability of BSWs removes the dependence on just the surface mode for obtaining coupled emission from 1DPCs. The observation of IMCE is expected to widen the scope of 1DPCs for surface-based fluorescence sensing and assays.
Understanding blue shift of the longitudinal surface plasmon resonance during growth of gold nanorods
Authors: Sahu Aditya K , Das Anwesh , Ghosh Anirudha , Raj Satyabrata
Published: January 2021

We have investigated in detail the growth dynamics of gold nanorods with various aspect ratios in different surrounding environments. Surprisingly, a blue shift in the temporal evolution of colloidal gold nanorods in aqueous medium has been observed during the growth of nanorods by UV–visible absorption spectroscopy. The longitudinal surface plasmon resonance peak evolves as soon as the nanorods start to grow from spheres, and the system undergoes a blue shift in the absorption spectra. Although a red-shift is expected as a natural phenomenon during the growth process of all nano-systems, our blue shift observation is regarded as a consequence of competition between the parameters of growth solution and actual growth of nanorods. The growth of nanorods contributes to the red-shift which is hidden under the dominating contribution of the growth solution responsible for the observed massive blue shift.
Half-space type theorem for translating solitons of the mean curvature flow in Euclidean space
Authors: Kim Daehwan , Pyo Juncheol
Published: January 2021

In this paper, we determine which half-space contains a complete translating soliton of the mean curvature flow and it is related to the well-known half-space theorem for minimal surfaces. We prove that a complete translating soliton does not exist with respect to the velocity

v

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in a closed half-space
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v

{\mathrm {v}}

in a right circular cone
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.
Above-ground biomass references for urban trees from terrestrial laser scanning data
Authors: Kükenbrink Daniel , Gardi Oliver , Morsdorf Felix , Thürig Esther , Schellenberger Andreas , Mathys Lukas
Published: January 2021

Background and Aims

Within extending urban areas, trees serve a multitude of functions (e.g. carbon storage, suppression of air pollution, mitigation of the ‘heat island’ effect, oxygen, shade and recreation). Many of these services are positively correlated with tree size and structure. The quantification of above-ground biomass (AGB) is of especial importance to assess its carbon storage potential. However, quantification of AGB is difficult and the allometries applied are often based on forest trees, which are subject to very different growing conditions, competition and form. In this article we highlight the potential of terrestrial laser scanning (TLS) techniques to extract highly detailed information on urban tree structure and AGB.

Methods

Fifty-five urban trees distributed over seven cities in Switzerland were measured using TLS and traditional forest inventory techniques before they were felled and weighed. Tree structure, volume and AGB from the TLS point clouds were extracted using quantitative structure modelling. TLS-derived AGB estimates were compared with AGB estimates based on forest tree allometries dependent on diameter at breast height only. The correlations of various tree metrics as AGB predictors were assessed.

Key Results

Estimates of AGB derived by TLS showed good performance when compared with destructively harvested references, with an R2 of 0.954 (RMSE = 556 kg) compared with 0.837 (RMSE = 1159 kg) for allometrically derived AGB estimates. A correlation analysis showed that different TLS-derived wood volume estimates as well as trunk diameters and tree crown metrics show high correlation in describing total wood AGB, outperforming tree height.

Conclusions

Wood volume estimates based on TLS show high potential to estimate tree AGB independent of tree species, size and form. This allows us to retrieve highly accurate non-destructive AGB estimates that could be used to establish new allometric equations without the need for extensive destructive harvesting.
Local Infiltration of Tranexamic Acid (TXA) in Liposuction: A Single-Surgeon Outcomes Analysis and Considerations for Minimizing Postoperative Donor Site Ecchymosis
Authors: Weissler Jason M , Banuelos Joseph , Molinar Vanessa E , Tran Nho V
Published: January 2021

Background

Tranexamic acid (TXA) has gained increasing recognition in plastic surgery as a dependable adjunct capable of minimizing blood loss, ecchymosis, and edema. To date, there have been limited data on the utilization of TXA to mitigate liposuction donor site ecchymosis.

Objectives

The authors sought to investigate whether infiltration of TXA into liposuction donor sites safely reduces postoperative ecchymosis.

Methods

A single-surgeon retrospective cohort study was performed to analyze patients undergoing autologous fat transfer for breast reconstruction between 2016 and 2019. Following lipoaspiration, patients in the intervention group received 75 mL of TXA (3 g in NaCl 0.9%) infiltrated into the liposuction donor sites, whereas the historical controls did not. Patient demographics, degree of ecchymosis, surgical complications, and thromboembolic events were examined. A blinded assessment of postoperative photographs of the donor sites was performed.

Results

Overall, 120 autologous fat grafting procedures were reviewed. Sixty patients received TXA, whereas 60 patients did not. Patient demographics and comorbidities were similar among the groups. No difference existed between groups regarding donor site locations, tumescent volume, lipoaspirate volume, or time to postoperative photograph. Ten blinded evaluators completed the assessment. The median bruising score of patients who received TXA was significantly lower than that of patients who did not (1.6/10 vs 2.3/10, P = 0.01). Postoperative complications were similar among the groups. Adverse effects of TXA were not observed.

Conclusions

Patients who received local infiltration of TXA into the liposuction donor sites were found to have less donor site ecchymosis than patients who did not. Further prospective randomized studies are warranted.

Level of Evidence: 4
Feature extraction approaches for biological sequences: a comparative study of mathematical features
Authors: Bonidia Robson P , Sampaio Lucas D H , Domingues Douglas S , Paschoal Alexandre R , Lopes Fabrício M , de Carvalho André C P L F , Sanches Danilo S
Published: January 2021

As consequence of the various genomic sequencing projects, an increasing volume of biological sequence data is being produced. Although machine learning algorithms have been successfully applied to a large number of genomic sequence-related problems, the results are largely affected by the type and number of features extracted. This effect has motivated new algorithms and pipeline proposals, mainly involving feature extraction problems, in which extracting significant discriminatory information from a biological set is challenging. Considering this, our work proposes a new study of feature extraction approaches based on mathematical features (numerical mapping with Fourier, entropy and complex networks). As a case study, we analyze long non-coding RNA sequences. Moreover, we separated this work into three studies. First, we assessed our proposal with the most addressed problem in our review, e.g. lncRNA and mRNA; second, we also validate the mathematical features in different classification problems, to predict the class of lncRNA, e.g. circular RNAs sequences; third, we analyze its robustness in scenarios with imbalanced data. The experimental results demonstrated three main contributions: first, an in-depth study of several mathematical features; second, a new feature extraction pipeline; and third, its high performance and robustness for distinct RNA sequence classification. Availability:https://github.com/Bonidia/FeatureExtraction_BiologicalSequences
MendelVar: gene prioritization at GWAS loci using phenotypic enrichment of Mendelian disease genes
Authors: Sobczyk M K , Gaunt T R , Paternoster L
Published: January 2021

Motivation

Gene prioritization at human GWAS loci is challenging due to linkage-disequilibrium and long-range gene regulatory mechanisms. However, identifying the causal gene is crucial to enable identification of potential drug targets and better understanding of molecular mechanisms. Mapping GWAS traits to known phenotypically relevant Mendelian disease genes near a locus is a promising approach to gene prioritization.

Results

We present MendelVar, a comprehensive tool that integrates knowledge from four databases on Mendelian disease genes with enrichment testing for a range of associated functional annotations such as Human Phenotype Ontology, Disease Ontology and variants from ClinVar. This open web-based platform enables users to strengthen the case for causal importance of phenotypically matched candidate genes at GWAS loci. We demonstrate the use of MendelVar in post-GWAS gene annotation for type 1 diabetes, type 2 diabetes, blood lipids and atopic dermatitis.

Availability and implementation

MendelVar is freely available at https://mendelvar.mrcieu.ac.uk

Supplementary information

Supplementary data are available at Bioinformatics online.
Development and Bio-Analytical Validation of Chromatographic Determination Method of Rufinamide in Presence of its Metabolite in Human Plasma
Authors: Hassib Sonia T , Hashem Hanaa M A , Mahrouse Marianne A , Mostafa Eman A
Published: January 2021

Rufinamide (RF), antiepileptic drug, is biotransformed to inactive metabolite. Frequent plasma monitoring is required for dose adjustment. This work is concerned with the development and validation of a sensitive and selective RP-HPLC method for the quantitative determination of RF in spiked human plasma in the presence of its main metabolite. Lacosamide was selected as internal standard. Preparation of plasma samples involved precipitation of plasma proteins using methanol. Isocratic elution mode was applied and the chromatographic separation was performed on Prontosil CN column (5 μm, 250 × 4.6 mm). Good resolution was achieved using acetonitrile: water (10:90, v/v, adjusted with 0.01 N aqueous solution of o-phosphoric acid to pH = 3) as a mobile phase at a flow rate of 1 mL/min, and UV detection was carried out at 210 nm. Linearity was observed over the concentration range of 0.5–50 μg/mL of RF in plasma. Bio-analytical validation of the developed method was carried out in accordance to the European Medicines Agency guidelines. The accuracy ranged from 95.97 to 114.13%, and the coefficient of variation of the assay intra-day and inter-day precision did not exceed 10%. The samples were stable under the employed experimental conditions. In conclusion, the findings of the present study revealed its usefulness for therapeutic drug monitoring, assessment of drug pharmacokinetics and application for bioequivalence study.
Reciprocal organ interactions during heart failure: a position paper from the ESC Working Group on Myocardial Function
Authors: Ciccarelli Michele , Dawson Dana , Falcao-Pires Inês , Giacca Mauro , Hamdani Nazha , Heymans Stéphane , Hooghiemstra Astrid , Leeuwis Annebet , Hermkens Dorien , Tocchetti Carlo Gabriele , van der Velden Jolanda , Zacchigna Serena , Thum Thomas
Published: January 2021

Heart failure—either with reduced or preserved ejection fraction (HFrEF/HFpEF)—is a clinical syndrome of multifactorial and gender-dependent aetiology, indicating the insufficiency of the heart to pump blood adequately to maintain blood flow to meet the body’s needs. Typical symptoms commonly include shortness of breath, excessive fatigue with impaired exercise capacity, and peripheral oedema, thereby alluding to the fact that heart failure is a syndrome that affects multiple organ systems. Patients suffering from progressed heart failure have a very limited life expectancy, lower than that of numerous cancer types. In this position paper, we provide an overview regarding interactions between the heart and other organ systems, the clinical evidence, underlying mechanisms, potential available or yet-to-establish animal models to study such interactions and finally discuss potential new drug interventions to be developed in the future. Our working group suggests that more experimental research is required to understand the individual molecular mechanisms underlying heart failure and reinforces the urgency for tailored therapeutic interventions that target not only the heart but also other related affected organ systems to effectively treat heart failure as a clinical syndrome that affects and involves multiple organs.
Impairment of Tissue-Resident Mesenchymal Stem Cells in Chronic Ulcerative Colitis and Crohn’s Disease
Authors: Grim Carl , Noble Robert , Uribe Gabriela , Khanipov Kamil , Johnson Paul , Koltun Walter A , Watts Tammara , Fofanov Yuriy , Yochum Gregory S , Powell Don W , Beswick Ellen J , Pinchuk Irina V
Published: January 2021

Background and Aims

Little is known about the presence and function of tissue-resident mesenchymal stem cells [MtSCs] within the gastrointestinal mucosa in health and inflammatory bowel disease [IBD]. The contribution of MtSCs to the generation of inflammatory fibroblasts during IBD is also poorly understood. We hypothesized that IBD-MtSCs are impaired and contribute to the generation of the pathological myofibroblasts in IBD.

Methods

In a cohort of clinically and endoscopically active IBD patients and normal controls, we used quantitative RT-PCR and stem cell differentiation assays, as well as confocal microscopy, to characterize MtSCs.

Results

Expression of two stem cell markers, Oct4 and ALDH1A, was increased in the inflamed IBD colonic mucosa and correlated with an increase of the mesenchymal lineage marker Grem1 in ulcerative colitis [UC], but not Crohn’s disease [CD]. Increased proliferation and aberrant differentiation of Oct4+Grem1+ MtSC-like cells was observed in UC, but not in CD colonic mucosa. In contrast to normal and UC-derived MtSCs, CD-MtSCs lose their clonogenic and most of their differentiation capacities. Our data also suggest that severe damage to these cells in CD may account for the pathological PD-L1low phenotype of CD myofibroblasts. In contrast, aberrant differentiation of MtSCs appears to be involved in the appearance of pathological partially differentiated PD-L1high myofibroblasts within the inflammed colonic mucosa in UC.

Conclusion

Our data show, for the first time, that the progenitor functions of MtSCs are differentially impaired in CD vs UC, providing a scientific rationale for the use of allogeneic MSC therapy in IBD, and particularly in CD.
The role of myocardial innervation imaging in different clinical scenarios: an expert document of the European Association of Cardiovascular Imaging and Cardiovascular Committee of the European Association of Nuclear Medicine
Authors: Gimelli Alessia , Liga Riccardo , Agostini Denis , Bengel Frank M , Ernst Sabine , Hyafil Fabien , Saraste Antti , Scholte Arthur J H A , Verberne Hein J , Verschure Derk O , Slart Riemer H J A
Published: January 2021

Cardiac sympathetic activity plays a key role in supporting cardiac function in both health and disease conditions, and nuclear cardiac imaging has always represented the only way for the non-invasive evaluation of the functional integrity of cardiac sympathetic terminals, mainly through the use of radiopharmaceuticals that are analogues of norepinephrine and, in particular, with the use of 123I-mIBG imaging. This technique demonstrates the presence of cardiac sympathetic dysfunction in different cardiac pathologies, linking the severity of sympathetic nervous system impairment to adverse patient’s prognosis. This article will outline the state-of-the-art of cardiac 123I-mIBG imaging and define the value and clinical applications in the different fields of cardiovascular diseases.
Spreading Uncertainty, Shrinking Birth Rates: A Natural Experiment for Italy
Authors: Comolli Chiara L , Vignoli Daniele
Published: January 2021

Many previous studies have documented the procyclicality of fertility to business cycles or labour market indicators in Western countries. However, part of the recent fertility decline witnessed since the Great Recession has been left unexplained by traditional measures. The present study advances the notion that birth postponement might have accelerated in response to rising uncertainty, which fuelled negative expectations and declining levels of confidence about the future. To provide empirical support for the causal effect of perceived uncertainty on birth rates, we focus on Italy’s sovereign debt crisis of 2011–2012 as a natural experiment. Perceived uncertainty is measured using Google trends for the term ‘spread’—which acted as somewhat of a barometer for the crisis both in the media and everyday conversations—to capture the general public’s degree of concern about the stability of Italian public finances. A regression discontinuity in time identifies the effect of perceived uncertainty on birth rates in Italy as a drop between 1.5% and 5%, depending on model specification.
LABORATORY STUDIES BEARING ON PIGMENT PATTERN POLYMORPHISMS IN WILD POPULATIONS OF RANA PIPIENS
Authors: Merrell David J
Published: January 2021

Data are presented for 2,393 progeny from a number of crosses related to a study in ecological genetics of the Burnsi and Kandiyohi polymorphisms in natural populations of the leopard frog, Rana pipiens. No significant differences in viability were found between wild-type homozygotes (+/+) and Burnsi heterozygotes (B/+) or homozygotes (B/B). Similarly, no difference in viability was found between wild-type (+/+) and Kandiyohi heterozygotes (K/+) and homozygotes (K/K). However, there appears to be slight reduction in viability of the double dominant heterozygote (B/+; K/+) in comparison with (+/+), (B/+), and (K/+) progeny from the same cross.—The Kandiyohi heterozygotes (K/+) appeared to have a more rapid rate of development from fertilization through metamorphosis than wild-type (+/+) or Burnsi (B+/) or Burnsi-Kandiyohi heterozygotes (B+K/+). Since Kandiyohi is associated primarily with the prairie habitat (Merrell 1965), this finding suggests that the adaptive advantage of Kandiyohi lies in the more rapid rate of development of frogs carrying this gene, enabling them to complete metamorphosis before the prairie breeding ponds dry up.—Data are presented from crosses involving dorsal spot number. The results suggest that heredity plays a role in the determination of dorsal spot number but that non-genetic influences are also of considerable importance.—The results of these crosses are discussed with respect to their bearing on the formation of pigment patterns in Rana pipiens. From the available data it is clear that the pigment pattern in Rana pipiens is a complex trait influenced by major gene loci, by modifying genes, and by environmental effects. The relative importance of these factors varies depending on the particular combination of genetic and environmental conditions.
ENZYME VARIABILITY IN THE DROSOPHILA WILLISTONI GROUP. III. AMOUNTS OF VARIABILITY IN THE SUPERSPECIES, D. PAULISTORUM
Authors: Richmond Rollin C
Published: January 2021

The semispecies composing the superspecies, Drosophila paulistorum, have been analyzed for genetic variation at 17 enzyme loci. On the average a population of D. paulistorum is polymorphic for 55–67% of its loci and an average individual is heterozygous at 21% of its loci. The pattern of genetic variability found supports the hypothesis that allozyme variation is maintained in natural populations by some form of balancing selection. Evidence is presented which supports the hypothesis that glucose-metabolizing enzymes are less genetically variable than non-glucose-metabolizing enzymes. The known genetic relationships between the semispecies of D. paulistorum are discussed in the light of the frequencies of alleles at allozyme loci.
ON THE GENETIC CONTROL OF GENES LOCATED IN THE SEX-CHROMOSOME HETEROCHROMATIN OF DROSOPHILA MELANOGASTER
Authors: Sandler L
Published: January 2021

The genetic properties of a recessive autosomal point mutant, "daughterless" (symbol: da), are described. They are: (1) da maps in the euchromatin of 2L at about position 39 on the genetic map and between 27D and 31E on the salivary map; (2) when homozygous in females, da causes the production of unisexual male progenies owing to sex differential zygote mortality in the egg stage; (3) da has no effect on the progeny of mutant males; (4) female zygotes die, while at least some male zygotes survive, irrespective of the number of Y chromosomes or the amount of X-chromosome heterochromatin carried by either the mutant female or her progeny; (5) homozygous da progeny of heterozygous parents also show sex differential survival favoring males indicating a da effect in development as well as in oogenesis, but with the developmental effect much less pronounced; (6) extra heterochromatin from either the X or Y chromosome in either the mother or her progeny can reduce the mortality caused by da in development (and, therefore, conceivably can also reduce the abnormality in oogenesis, although this is obscured by the seventy of the maternal effect.)——From these results, it is suggested that (1) da regulates either the activity of structural genes in the sex chromosome heterochromatin or the activity or stability of their products, and (2) it is a defective product of sex chromosome heterochromatic genes that causes the abnormalities resulting in the observed mortality of heterozygous progeny of homozygous mutant m3thers and of homozygous mutant progeny of heterozygous mothers.——The striking parallels with the properties of the gene, "abnormal oocyte" are noted as is the close linkage between the two loci. The possibility of a special sex-chromosome-heterochromatin-regulator region on chromosome 2 is considered.
INTERACTIONS OF DIFFERENTIATED PRIMARY SEX FACTORS IN CHIRONOMUS TENTANS
Authors: Thompson Peter E , Bowen Jean S
Published: January 2021

Different populations of Chironomus tentans, possibly representing geographically isolated races, have two differentiated genic mechanisms of sex determination involving either a dominant male-determining factor in the left arm of chromosome 1 or a dominant female-determining factor at the right tip of chromosome 1. In crosses between these populations, the male-determining factor is epistatic to the female-determining factor. No evidence of intersexuality has been found in such crosses.
EXTRACHROMOSOMAL ELEMENT DELTA IN DROSOPHILA MELANOGASTER. VII. RELATION TO FERTILITY IN A SECOND-CHROMOSOME LINE
Authors: Minamori Sumio , Ito Kazuko
Published: January 2021

The IDb-45 chromosome line usually carries an appreciable amount of delta b, but it is not susceptible to the killing action of this delta. The fertility of this line was examined when it carried various amounts of delta b. More than one third of the Cy/IDb-45 males and females tested became sterile when they carried cytoplasm of the Cy/Pm stock which is assumed to carry no delta b. The number of progeny is smaller when flies of this line are raised at 25°C than at 28°C at which temperature the multiplication of delta is accelerated. The progeny number was appreciably reduced when the flies were raised at 18°C at which temperature the multiplication of delta is suppressed. This line could not be maintained at that temperature, since both males and females became sterile. Thus, the conclusion may be drawn that the presence of an appreciable amount of delta b is necessary for the gametogenesis of the Cy/IDb-45 flies.
GENETICS OF SOMATIC FUSION IN PHYSARUM POLYCEPHALUM: THE PpII STRAIN
Authors: Collins O'Neil Ray , Haskins Edward F
Published: January 2021

Plasmodial (somatic) fusion in a strain of Physarum polycephalum, a true slime mold, is controlled by four loci, each of which displays simple dominance. Two diploid plasmodia fuse with each other only if they are phenotypically or genotypically identical for all four fusion loci.
THE EFFECT OF ABNORMAL CHROMOSOME 10 ON TRANSPOSITION OF MODULATOR FROM THE R LOCUS IN MAIZE
Authors: Williams Elizabeth , Brink R Alexander
Published: January 2021

Transposition of the non-specific repressor element, Modulator, from the R locus on chromosome 10 in maize, is enhanced by coupling with the K10 segment at a distance of at least 35 map units from R. There is no detectable interaction in the repulsion phase. The K10 effect appears to be relatively greater in the earlier somatic cell generations during ear development. The transposition rate also is affected by the direction of crosses, being somewhat higher on the ears of F1 plants which received the compound mutable R allele from the pollen parent. The significance of the behavior of Modulator and other instability phenomena of higher plants is discussed in relation to chromosome organization.
ISOLATION OF PLAQUE-FORMING, GALACTOSE-TRANSDUCING STRAINS OF PHAGE LAMBDA
Authors: Feiss Michael , Adyha Sankar , Court Donald L
Published: January 2021

Plaque-forming, galactose-transducing lambda strains have been isolated from lysogens in which bacterial genes have been removed from between the galactose operon and the prophage by deletion mutation.—A second class has been isolated starting with a lysogenic strain which carries a deletion of the genes to the right of the galactose operon and part of the prophage. This strain was lysogenized with a second lambda phage to yield a lysogen from which galactose-transducing, plaque-forming phages were obtained. These plaque-forming phages were found to be genetically unstable, due to a duplication of part of the lambda chromosome. The genetic instability of these partial diploid strains is due to homologous genetic recombindation between the two identical copies of the phage DNA comprising the duplication. The galactose operon and the duplication of phage DNA carried by these strains is located between the phage lambda P and Q genes.
NONSENSE MUTATIONS IN THE ADE3 LOCUS OF SACCHAROMYCES CEREVISIAE
Authors: Jones Elizabeth W
Published: January 2021

Fifty seven mutations at the ade3 locus have been crossed to ochre, amber and ochre-amber suppressors. 70% (39/56) of the mutations at this locus are nonsense mutations; 61% (34/56) are ochre mutations and 9% (5/56) are amber mutations. The frequency of nonsense mutations among ade3 alleles recovered is very high and raises the interesting possibility that only polar mutations at this locus are recovered. An hypothesis to explain these genetical findings as well as physiological properties of these mutations is proposed.
A METHOD FOR OBTAINING ANTIBIOTIC-SENSITIVE MUTANTS IN SACCHAROMYCES CEREVISIAE
Authors: Littlewood Barbara S
Published: January 2021

We have isolated a temperature-sensitive mutant of S. cerevisiae which has proven useful for the isolation of antibiotic-sensitive strains.
DIFFERENCES IN SYNAPTIC AFFINITY OF CHROMOSOME ARMS OF DROSOPHILA MELANOGASTER REVEALED BY DIFFERENTIAL SENSITIVITY TO TRANSLOCATION HETEROZYGOSITY1
Authors: Roberts Paul A
Published: January 2021

The chromosome arms of Drosophila melanogaster differ in the degree to which translocation heterozygosity suppresses crossing over both regionally, and as whole arms. We have identified the region of maximum sensitivity to structural heterozygosity in each arm of the long autosomes ⅓ to ½ the length of the arm in from the tip. We interpret the regional differences as further indication that synapsis usually begins distally, but not at the telomeres. We interpret the different sensitivity of arms 3R, 2R, 3L and 2L (ranked in order of increasing sensitivity) as evidence of intrinsic differences in the synaptic affinity of chromosome arms.
TEMPERATURE-SENSITIVE MUTANTS OF ANACYSTIS NIDULANS
Authors: Kaney Anthony R , Dolack Mary P
Published: January 2021

One hundred forty-two temperature-sensitive mutants of Anacystis nidulans were isolated. None are supplementable at the non-permissive temperature, suggesting the possibility that mutations resulting in auxotrophy are lethal in this organism.
NONSENSE MUTATION IN THE REGULATORY GENE ETH2 INVOLVED IN METHIONINE BIOSYNTHESIS IN SACCHAROMYCES CEREVISIAE
Authors: Masselot M , de Robichon-Szulmajster H
Published: January 2021

Ethionine-resistant mutants, mapping at the locus eth2—the product of which is involved in pleiotropic regulation of methionine biosynthesis—have been isolated in a strain carrying five ochre nonsense mutations. Selection for nonsense suppressors in such a strain led to characterization of several allele-specific but gene non-specific suppressors which are active on the recessive heteroallele eth2–2 (resulting in partial recovery of sensitivity toward ethionine) as well as on the five other suppressible alleles. Two of these suppressors are unlinked to the eth2 gene and either dominant or semi-dominant. It is concluded that the mutation eth2–2 resulted in a nonsense codon. Enzyme studies indicate that this mutation results in a complete absence of an active product of gene eth2, in contrast with the effect of a former mutation eth2–1 which was interpreted as leading to a modified product of this gene (Cherest, Surdin-Kerjan and de Robichon-Szulmajster 1971). This conclusion is based on the absence of repressibility of methionine group I enzymes and the observation that in a heteroallelic diploid, eth2–1 expression is not masked by eth2–2. The nonsense suppressors studied lead to at least partial recovery of repressibility of methionine group I enzymes. All these results support the idea that the product of gene ETH2 is an aporepressor protein.
INHERITANCE DURING PARTHENOGENESIS IN DAPHNIA MAGNA
Authors: Hebert P D N , Ward R D
Published: January 2021

Natural populations of Daphnia magna have been found which are polymorphic for electrophoretic variants of supernatant malic dehydrogenase, esterase, and alkaline phosphatase. Using these enzyme variants as genetic markers it has been possible to demonstrate the absence of recombination during parthenogenetic reproduction. Genetic uniformity is expected within parthenogenetic clones derived from a single female.
CHARACTERIZATION OF CHICKEN b-LOCUS (IgG) ALLOTYPES
Authors: David C S
Published: January 2021

Chicken allotypes b1 and b2 are controlled by allelic genes and associated with the IgG class of immunoglobulins. The determinants cannot be detected on either isolated heavy and light polypeptide chains or the enzymatic fragments. The results suggest that either the intact IgG molecule is required for their expression or the conditions normally used for isolation of the subunits destroy or modify the antigenic specificities in chickens.
A MODEL FOR THE GENETICS OF HANDEDNESS
Authors: Levy Jerre , Nagylaki Thomas
Published: January 2021

Experimental data and theoretical work on the inheritance of handedness and cerebral dominance are reviewed. A two-gene, four-allele model, one locus pertaining to left or right hemispheric dominance and the other to contralateral or ipsilateral hand control relative to the dominant hemisphere, is constructed. It is in excellent agreement with all quantitative information regarding this problem. Refinements designed to explain relevant qualitative facts are proposed and discussed.
DIRECT EVIDENCE OF GENIC DIFFERENTIATION BETWEEN SEX RATIO AND STANDARD GENE ARRANGEMENTS OF X CHROMOSOME IN DROSOPHILA PSEUDOOBSCURA
Authors: Prakash Satya , Merritt R B
Published: January 2021

Evidence of strong association of alleles at the Esterase-5 and adult Acid phosphatase-6 loci with the Sex Ratio and the Standard X chromosome arrangements in D. pseudoobscura is presented. There is no differentiation at these two loci, either in the Sex Ratio or the Standard arrangement from two widely separated geographic populations. At the Esterase-5 locus, alleles characteristic of one arrangement are found in low frequencies in the other arrangement. It is concluded, from these and other observations that the differentiation between the Sex Ratio and the Standard arrangement, at these two loci, is a result of natural selection favoring different coadapted gene blocks in these arrangements. The average heterozygosity at these two loci in different karyotypes is in the following order: ST/SR > ST/ST >> SR/SR which agrees very well with the fitness estimates of these karyotypes.
CHANGING POPULATION STRUCTURE THROUGH THE USE OF COMPOUND CHROMOSOMES
Authors: Childress D
Published: January 2021

Theoretical calculations and population cage data are presented to illustrate the use of compound chromosomes to change the genetic structure of insect populations.
TRANSITORY HETEROSIS IN NUMBERS OF BASAL BODIES IN TETRAHYMENA PYRIFORMIS
Authors: Nanney D L , Doerder F P
Published: January 2021

The numbers of kinetosomes in ciliary rows on the ventral surface of cells of Tetrahymena pyriformis, syngen 1, are greater by about 10% in young heterozygotes established by crossing two inbred strains than in either homozygote. The difference, apparent at 20 fissions post-fertilization, is essentially gone by 100 fissions. This observation is consistent with a generalized "allelic exclusion" at all loci completed by perhaps 60 fissions after fertilization.
GENETIC MAP OF THE LACTOSE REPRESSOR GENE (i) OF ESCHERICHIA COLI
Authors: Pfahl Magnus
Published: January 2021

39 tonB i- deletions were used to map 57 independently isolated i gene mutants. Methods selective for i+ recombinants from various types of i mutants are described. i+ recombination frequencies of 6 × 10-6 to 6 × 10-7 can be detected in the different selective systems. Twenty i  s mutations and 12 i  -d mutations map in distinct but different regions of the gene. i  -  sus mutations are scattered over the gene.
SATELLITE DNAs IN THE EMBRYOS OF VARIOUS SPECIES OF THE GENUS DROSOPHILA
Authors: Travaglini E C , Petrovic J , Schultz J
Published: January 2021

A tentative evolutionary pattern has been found for two classes of the multiple satellite DNA's found in the genus Drosophila. The satellite DNA's from five Drosophila species (D. melanogaster, D. simulans, D. nasuta, D. virilis and D. hydei) were analyzed and found to fall into three arbitrary CsCl buoyant density classes: Class I, ρ = 1.661-1.669 g cm-3, DNA molecules composed of primarily dA and dT moieties; Class II, ρ = 1.685 and ρ = 1.692, DNA molecules of low GC content; and Class III, ρ = 1.711, a DNA of high GC composition. The dAT satellite DNA's appear in all the species studied except D. hydei, the species of most recent evolutionary divergence, whereas the heavy satellite appears only in the two species of most recent divergence, D. virilis and D. hydei.
ANALYSIS OF COMPLEX ALLOZYME POLYMORPHISMS IN A BARLEY POPULATION
Authors: Weir B S , Allard R W , Kahler A L
Published: January 2021

Genotypes of 68,230 individuals taken from 10 generations (F4-F6, F14-F17, F24-F26) of an experimental population of barley were determined for four esterase loci. The results show that frequencies of gametic ditypes changed significantly over generations and that striking gametic phase disequilibrium developed within a few generations for each of the six pairwise combinations of loci which were monitored. The complex behavior of these four enzyme loci in the population is attributed to interactions between selection and restriction of recombination resulting from the effects of linkage and/or inbreeding.
INFLUENCE OF BACKGROUND GENOME ON ENZYMATIC CHARACTERISTICS OF YELLOW (Ay/-, Avy/-) MICE
Authors: Wolff George L , Pitot Henry C
Published: January 2021

dentification of the fundamental polypeptide difference between yellow (Ay/-, Avy/-) and non-yellow mice is important for biomedical research because of the influence of the yellow genotype on normal and neoplastic growth and obesity. The complexity of the "yellow mouse syndrome" makes attainment of this objective dependent on the separation of those pleiotropic enzyme differences which are secondary, and depend on the background genome, from those which are primary, and depend primarily on the agouti locus genotype.—Four of nine hepatic enzyme activities assayed simultaneously differed between eight-week-old yellow (Ay/-, Avy/-) and non-yellow (A/-, a/a) male inbred and F1 hybrid mice. Among these four, only cytoplasmic malic enzyme activity was elevated in all yellow mice, as compared with the non-yellow sibs, regardless of background genome. Glucokinase, serine dehydratase, and tyrosine α-ketoglutarate transaminase activities were also changed in yellow mice, but these alterations depended on the background genome.—The ratio of malic enzyme activity to citrate-cleavage enzyme activity, possibly related to the altered fat metabolism of yellow mice, was influenced by background genome as well as by the yellow genotype.—Significant deviations of enzyme activities from mid-parent values among F1 hybrids were associated with particular background genomes; the number of such deviations was larger among yellow mice than among non-yellows and this difference was greater among C3H F1 hybrids than among C57BL/6 F1 hybrids.
GENOTYPE-TEMPERATURE INTERACTION IN DROSOPHILA MELANOGASTER. II. BODY WEIGHT
Authors: Fontdevila Antonio
Published: January 2021

The effect of genotype-temperature interactions on body weight has been studied in a natural population of Drosophila melanogaster using four isogenic strains derived from it, and their hybrid F1 and F2 progenies. Measurements were made at four constant temperatures–25°, 21°, 17° and 13°C—and at a temperature oscillating between 17° and 25°C.—Low, though significant, genotype-temperature interaction exists among the isogenic strains, but not among the F1 nor F2 hybrid progenies. These low interaction values may be due to the fact that all isogenic strains have a common origin and therefore presumably little genic divergence exists among them. F1 and F2 hybrid progenies generally exhibit higher homeostasis than the isogenic strains, although one isogenic line has better homeostasis than the majority of the hybrids.—There is no evidence of heterosis and some evidence of dominance. These results are consistent with the hypothesis that body weight is regulated mainly by additive genetic factors and is subject to stabilizing selection.
PRE-MEIOTIC DNA SYNTHESIS AND RECOMBINATION IN CHLAMYDOMONAS REINHARDI
Authors: Chiu S M , Hastings P J
Published: January 2021

The time of the pre-meiotic S-period was determined by 32P incorporation in synchronously germinating zygospores of Chlamydomonas reinhardi at six and one-half to seven hours after the beginning of germination. Phenethyl alcohol treatment caused death of zygospores at a period one hour before the S-period, and also during meiotic prophase. Recombination between arg-1 and arg-2 was increased by treatment with phenethyl alcohol or mitomycin C at a time between the first sensitive period to phenethyl alcohol and the S-period. Actinomycin D caused an increase in recombination at the time of this sensitive period. FUdR, nalidixic acid and hydroxurea all cause a decrease in recombination when applied during S-period, and have no effect earlier. These results are explained by postulating (1) that the units of delayed premeiotic replication are whole replicons, and (2) that the amount of recombination is proportional to the number of replicons in which synthesis is delayed. It is suggested that the control of DNA replication controls the distribution of recombination events.
REGULATION OF RIBOSOMAL RNA GENE MULTIPLICITY IN DROSOPHILA MELANOGASTER
Authors: Tartof Kenneth D
Published: January 2021

The ribosomal RNA (rRNA) genes of Drosophila melanogaster can undergo a disproportionate replication of their number. This occurs when the cluster of rRNA genes (rDNA) of one chromosome is maintained with a homologous chromosome that is completely or partially deficient in its rDNA. Under appropriate genetic conditions, it appears that disproportionate rDNA replication can be generated at the level of both somatic and germ line cells. In the latter case, mutants partially deficient for rDNA can increase their rRNA gene number to the wild type level and transmit this new genotype to successive generations.
A NOTE ON THE MATERNAL EFFECT MUTANTS DAUGHTERLESS AND ABNORMAL OOCYTE IN DROSOPHILA MELANOGASTER
Authors: Mange Arthur P , Sandler L
Published: January 2021

Two deficiencies for, and a dominant enhancer of, the second chromosome maternal effect mutant, "daughterless" (da), were induced with X-irradiation. Their properties were studied with respect to both da and the linked maternal effect mutant, "abnormal oocyte" (abo), with the following conclusions. (1) The most probable map positions of da and abo are: J–½–da–2½–abo, where J is a dominant marker located at 41 on the standard map. (2) The da locus is in bands 31CD-F on the polytene chromosome map; abo is to the right of 32A. (3) Because homozygous da individuals survive while individuals carrying da and a deficiency for da are lethal, it is concluded that da is hypomorphic. (4) From a weak da-like maternal effect in heterozygous da females induced by an "Enhancer of da," we have confirmed a previous report that (a) the amount of sex chromosome heterochromatin contributed by the father can influence the severity of the da maternal effect, and (b) the sex chromosome heterochromatin which influences the da effect is different from that which influences the abo effect. (5) The possibility that da and abo are in a special region of chromosome 2 concerned with the regulation of sex chromosome heterochromatin is strengthened by the observation that the Enhancer of da appears to rescue abnormal eggs produced by homozygous abo mothers. (6) The Enhancer of da is a translocation between chromosomes 2 and 3 with the second chromosome breakpoint in the basal heterochromatin; because the enhancing effect maps in this region of chromosome 2, it is possible that autosomal, as well as sex chromosomal, heterochromatin interacts with da and abo.
RADIATION GENETICS IN MICROORGANISMS AND EVOLUTIONARY CONSIDERATIONS
Authors: Kondo Sohei
Published: January 2021

Recent knowledge of UV-resistance mechanisms in microorganisms is reviewed in perspective, with emphasis on E. coli. Dark-repair genes are classified into "excision" and "tolerance" (ability to produce a normal copy of DNA from damaged DNA). The phenotype of DNA repair is rather common among the microorganisms compared, and yet their molecular mechanisms are not universal. In contrast, DNA photoreactivation is the simplest and the most general among these three repair systems. It is proposed that DNA repair mechanisms evolved in the order: photoreactivation, excision repair, and tolerance repair. The UV protective capacity and light-inducible RNA photoreactivation possessed by some plant viruses are interpreted to be the result of solar UV selection during a rather recent era of evolution.
CYTOGENETICS OF CHROMOSOME PAIRING IN WHEAT
Authors: Riley Ralph
Published: January 2021

Meiotic chromosome pairing in Triticum aestivum is controlled by genetic systems promoting and reducing pairing. The pairing of homoeologous chromosomes is prevented principally by the activity of a single locus (Ph) distally located on the long arm of chromosome 5B. In certain hybrids, supernumerary chromosomes (B chromosomes) from Aegilops species can compensate for the absence of chromosome 5B preventing or reducing homoeologous pairing. Temperature-dependent variants and colchicine sensitivity have been used to show that there are at least two stages in the G1 of meiosis at which the occurrence of meiotic pairing is determined. Wheat may differ from lily in the detailed organization of meiosis.
CHROMOSOME SEGREGATION MECHANISMS
Authors: Nicklas R Bruce
Published: January 2021

Most aspects of chromosome distribution to the daughter cells in meiosis and mitosis are now understood, at the cellular level. The most striking evidence that the proposed explanation is valid is that it correctly predicts the outcome of experiments on living cells in which the experimenter (1) can determine the distribution of any chosen chromosome to a chosen daughter cell, (2) can induce a mal-orientation, and (3) can stabilize a mal-orientation, causing non-disjunction of a chosen bivalent. Recent reviews of chromosome distribution mechanisms are also considered, in an attempt to clarify the remaining unsolved problems.