bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECTS OF NONHOMOLOGY ON BACTERIOPHAGE LAMBDA RECOMBINATION
Authors: Lichten Michael , Fox Maurice S 
Published: January 2021

ABSTRACT
When crosses are performed under conditions severely restricting DNA synthesis, the presence of DNA sequence nonhomologies in the lac region of λplac5 limits the parental material contribution to and the yield of phage recombinant in a region bracketed by the nonhomologies. These observations are consistent with the expectation of a role for branch migration in the formation of heteroduplex structures under these conditions. Under conditions permissive for DNA replication, bracketing a region with nonhomologies has an only modest effect on the yield of recombinants within that interval. In addition, recombinants within such a bracketed interval manifest an excess of coincident exchange events in an adjacent region. These observations suggest the possibility that, under conditions permissive for DNA replication, regions of nonhomology can be included in heteroduplex structures.
CHROMOSOMAL LOCATION OF GENES CONTROLLING FLAVONOID PRODUCTION IN HEXAPLOID WHEAT
Authors: Neuman Paula R , Waines J G , Hilu K W , Barnhart D 
Published: January 2021

ABSTRACT
Two-dimensional paper chromatography was performed on methanol extracts of leaves of hexaploid bread wheat, Triticum aestivum L. em. Thell. cultivar Chinese Spring, and of the available nullisomic-tetrasomic compensating lines, the tetrasomic lines and the ditelocentric lines. The chromatograms had 27 spots identified as flavonoids and six representing phenolic acids. Some of the areas were complex and contained more than one compound. Four flavonoids were identified as under the control of gene(s) on chromosome arms 1DS, 4DL, 5AS and 6BS. A phenolic glycoside was concluded to be controlled by a gene(s) on chromosome arm 7BL. Gene(s) on chromosome arm 4DL affected the amount of compounds in two other spots, and gene(s) on chromosome arm 4BS reduced the level of all flavonoid compounds. The individual compounds in some of the complex spots may be under the control of gene(s) on homoeologous chromosomes.
REVERTANTS OF A TRANSCRIPTION TERMINATION MUTANT OF YEAST CONTAIN DIVERSE GENETIC ALTERATIONS
Authors: Kotval Jeroo , Zaret Kenneth S , Consaul Sandra , Sherman Fred 
Published: January 2021

ABSTRACT
Revertants of the cyc1-512 transcription termination mutant of the yeast Saccharomyces cerevisiae were isolated and subjected to a detailed genetic analysis. The cyc1-512 mutation previously was shown to be a 38-base pair deletion that causes only 10% of the normal steady-state levels of CYC1 mRNA and of the CYC1 gene product, iso-1-cytochrome c. Forty-one cyc1-512 revertants were classified by their content of iso-1-cytochrome c and by their genetic properties in meiotic crosses. Many of the revertants contain local genetic changes that either partially or completely restore the level of iso-1-cytochrome c. One revertant was shown to contain an unlinked extragenic suppressor, designated sut1, that causes partial suppression of the transcription termination defect. Four revertants of cyc1-512 contain chromosomal rearrangements with breakpoints that are tightly linked to the CYC1 locus; these include one duplication, one possible inversion, and two reciprocal translocations. Detailed genetic mapping demonstrated that one of the reciprocal translocations is between the right arms of chromosomes X and XII, with a breakpoint mapping 3′ to the CYC1 locus. These results indicate that the defect in transcription termination in cyc1-512 can be restored in a variety of ways, including the translocation of different chromosomal regions to the 3′ end of the CYC1 locus, local changes presumably at or near the original defect, and by mutation at another locus distinct from CYC1.
SELECTION IN PLANT POPULATIONS OF EFFECTIVELY INFINITE SIZE. V. BIALLELIC MODELS OF TRIOECY
Authors: Gregorius H R , Ross M D , Gillet E M 
Published: January 2021

ABSTRACT
A one-locus two-allele model of trioecy (presence of hermaphrodites, males and females in one population) is considered, in order to study the conditions for the persistence of this system. All possible assignments of the three sex types to the three genotypes are considered. This leads to three different modes of inheritance of trioecy, namely (a) females heterozygous, (b) males heterozygous and (c) hermaphrodites heterozygous, where in each mode each of the remaining two sex types is homozygous for one of the alleles. For mode (c) trioecy is always persistent, and the dependence of the sex ratio (for the three sex types) on the ovule and pollen fertilities and on the hermaphrodite selfing rate is specified. For the other two modes, (a) and (b), trioecy is not protected, i.e., it may not persist for any fertilities, viabilities or selfing rates. Thus, in this situation it is important to study the conditions under which the "marginal" systems of sexuality of trioecy, i.e., hermaphroditism, dioecy and gynodioecy in mode (a), and hermaphroditism, dioecy and androdioecy in mode (b), may become established. The results show that each marginal system may evolve from each other via trioecy. The evolution of dioecy is easier in mode (a) than in (b), so that female heterogamety would be expected to occur more often than male heterogamety in the present model. Under some conditions the breeding system obtained in equilibrium populations may depend on the initial genotype frequencies.—The necessity of considering modes of inheritance for sexual polymorphisms is demonstrated by comparing our results with those obtained from an evolutionary stable strategy (ESS) analysis of a purely phenotypic model.
MATERNAL-ZYGOTIC LETHAL INTERACTIONS IN DROSOPHILA MELANOGASTER: ZESTE-WHITE REGION SINGLE-CISTRON MUTATIONS
Authors: Robbins Leonard G 
Published: January 2021

ABSTRACT
Thirty-eight mutations in 13 essential loci in the zeste-white region were tested for interacting maternal and zygotic gene activity. Maternal mutant heterozygosity provided a partial maternal defect and position-effect variegation was used to alter the level of zygotic gene activity. This method yields a minimum estimate of the number of genes for which zygotic development depends upon both gene products stored in the egg and gene products synthesized in the zygote. Lethal interactions were found for one or more alleles at 10 of the 13 loci. The implications of these observations with respect to gene regulation and developmental sequence are considered.
FURTHER EVIDENCE FOR A POLYMORPHISM IN GAMETIC SEGREGATION IN THE TETRAPLOID TREEFROG HYLA VERSICOLOR USING A GLUTAMATE OXALOACETIC TRANSAMINASE LOCUS
Authors: Danzmann Roy G , Bogart James P 
Published: January 2021

ABSTRACT
Intra- and interspecific cross combinations between the tetraploid treefrog Hyla versicolor, and between H. versicolor and the diploid treefrog Hyla chrysoscelis were performed. Progeny phenotypes resulting from these crosses were examined electrophoretically using a polymorphic glutamate oxaloacetic transminase (GOT-1) locus, to determine the mechanism of chromosome segregation in H. versicolor, and to test theoretical expectations for isozyme expression in interspecific (2n × 4n or 4n × 2n) hybrids. In some intraspecific tetraploid crosses progeny phenotypes fit a disomic mode of segregation, whereas in other crosses a tetrasomic mode of segregation was the most probable. Additional crosses produced phenotypic ratios that conformed to either a disomic or tetrasomic mode of segregation. These results suggest that a polymorphism, with respect to segregation of gametes, exists in H. versicolor, resulting from differences in chromosome pairings during meiosis I. This polymorphism in gametic segregation occurred in both sexes. Certain crosses, however, produced phenotypic ratios that did not conform to any chromosome segregation model. Progeny phenotypes observed from most interspecific crosses conformed to expected interspecific isozyme staining intensity models. Symmetrical heterozygotes, representing either a single dose for both alternate alleles or double doses for both alternate alleles, were also observed. Such phenotypes are unexpected in triploid progeny. A null allele was postulated to account for the aberrant segregation ratios and phenotypes observed in certain intra- and interspecific crosses.
USE OF NYSTATIN-RESISTANT MUTATIONS IN PARASEXUAL GENETIC ANALYSIS IN DICTYOSTELIUM DISCOIDEUM
Authors: Kasbekar Durgadas P , Madigan Sanford , Katz Eugene R 
Published: January 2021

ABSTRACT
Nystatin-resistant mutations exhibit extreme sensitivity to 1.3 mm coumarin. The mutations fall into three complementation groups so it is possible to select for nonallelic mutations conferring sensitivity to coumarin by selection on nystatin-containing nutrient agar plates. Complementation between such coumarin-sensitive mutations allows the selection of diploids on coumarin-containing nutrient agar. Two of the nystatin resistance genes, nysB and nysC, have been mapped tentatively to the previously unmarked linkage group V.
GENETIC VARIATION IN PROTEINS: COMPARISON OF ONE-DIMENSIONAL AND TWO-DIMENSIONAL GEL ELECTROPHORESIS
Authors: McLellan Tracy , Ames Giovanna Ferro-Luzzi , Nikaido Kishiko 
Published: January 2021

ABSTRACT
Two proteins with known characteristics on one-dimensional gels were studied by two-dimensional electrophoresis to compare the sensitivities of the two methods in detecting genetic variation. Two-dimensional electrophoresis was found to be less sensitive than several types of one-dimensional gels in distinguishing variants of both proteins. Denaturation of proteins in urea in the two-dimensional method makes it possible to distinguish closely related proteins that differ from each other by units of charge. Many more types of variation in protein sequences can be distinguished on one-dimensional gels in the absence of denaturants. The estimates of heterozygosity based on two-dimensional gels are lower than those based on other methods, at least in part, because of the limited types of sequence differences that can be detected on two-dimensional gels. The application of two-dimensional electrophoresis to the measurement of genetic variation and to the detection of new mutations should be made carefully, in view of the limited sensitivity of the method in finding differences in sequence.
GENETIC EFFECTS OF UV IRRADIATION ON EXCISION-PROFICIENT AND -DEFICIENT YEAST DURING MEIOSIS
Authors: Resnick Michael A , Game John C , Stasiewicz Stanley 
Published: January 2021

ABSTRACT
The lethal and recombinational responses to ultraviolet light irradiation (UV) by excision-proficient (RAD +) and deficient strains (rad1) of Saccharomyces cerevisiae has been examined in cells undergoing meiosis. Cells that exhibit high levels of meiotic synchrony were irradiated either at the beginning or at various times during meiosis and allowed to proceed through meiosis. Based on survival responses, the only excision repair mechanism for UV damage available during meiosis is that controlled by the RAD1 pathway. The presence of pyrimidine dimers at the beginning of meiosis does not prevent cells from undergoing meiosis; however, the spore products exhibit much lower survival than cells from earlier stages of meiosis. The reduced survival is probably due to effects of UV on recombination. Meiotic levels of gene conversion are reduced only two to three times in these experiments; however, intergenic recombination is nearly abolished after a dose of 4 J/m2 to the rad1 strain. Exposure to 25 J/m2 had little effect on the wild-type strain. Since normal meiotic reciprocal recombination is generally considered to involve gene conversion-type intermediates, it appears that unrepaired UV damage dissociates the two processes. These results complement those obtained with the mei-9 mutants of Drosophila which also demonstrate a dissociation between gene conversion and reciprocal recombination. These results are consistent with molecular observations on the UV-irradiated rad1 strain in that there is no excision of pyrimidine dimers or exchange of dimers during meiosis.
EXPRESSION OF MATERNALLY AND EMBRYONICALLY DERIVED HYPOXANTHINE PHOSPHORIBOSYL TRANSFERASE (HPRT) ACTIVITY IN MOUSE EGGS AND EARLY EMBRYOS
Authors: Kratzer Paul G 
Published: January 2021

ABSTRACT
X-chromosome activity in early mouse development has been studied by a gene dosage method that involves measuring the activity level of the X-linked enzyme hypoxanthine phosphoribosyl transferase (HPRT) in single eggs and embryos from XO females and from females heterozygous for In(X)1H, a paracentric inversion of the X chromosome. The HPRT activity in oocytes increased threefold over a 24-hr period beginning after ovulation. Afterward, the activity plateaued in unfertilized eggs but continued to increase for at least 66 hr in presumed OY embryos. Both before and after ovulation, the level of activity in unfertilized eggs from In(X)/X females was twice that from XO females, and the distributions of activity in eggs for both sets of females remained unimodal. Beginning with the two-cell stage, distributions of activity for embryos from In(X)/X females were trimodal, which is evidence for embryonic activity. It is proposed that activation of a maternal mRNA or proenzyme is responsible for the HPRT activity increase in oocytes and early embryos and is supplemented by dosage-dependent activity of the embryonic Hprt gene as early as the two-cell stage.
MAXIMUM LIKELIHOOD ESTIMATION OF THE NUMBER OF NUCLEOTIDE SUBSTITUTIONS FROM RESTRICTION SITES DATA
Authors: Nei Masatoshi , Tajima Fumio 
Published: January 2021

ABSTRACT
A simple method of the maximum likelihood estimation of the number of nucleotide substitutions is presented for the case where restriction sites data from many different restriction enzymes are available. An iteration method, based on nucleotide counting, is also developed. This method is simpler than the maximum likelihood method but gives the same estimate. A formula for computing the variance of a maximum likelihood estimate is also presented.
O-GlcNAcAtlas: A database of experimentally identified O-GlcNAc sites and proteins
Authors: Ma Junfeng , Li Yaoxiang , Hou Chunyan , Wu Ci 
Published: January 2021

Abstract
O-linked β-N-acetylglucosamine (O-GlcNAc) is a post-translational modification (i.e., O-GlcNAcylation) on the serine/threonine residues of proteins. As a unique intracellular monosaccharide modification, protein O-GlcNAcylation plays important roles in almost all biochemical processes examined. Aberrant O-GlcNAcylation underlies the etiologies of a number of chronic diseases. With the tremendous improvement of techniques, thousands of proteins along with their O-GlcNAc sites have been reported. However, until now, there are few databases dedicated to accommodate the rapid accumulation of such information. Thus, O-GlcNAcAtlas is created to integrate all experimentally identified O-GlcNAc sites and proteins. O-GlcNAcAtlas consists of two datasets (Dataset-I and Dataset-II, for unambiguously identified sites and ambiguously identified sites, respectively), representing a total number of 4571 O-GlcNAc modified proteins from all species studied from 1984 to 31 Dec 2019. For each protein, comprehensive information (including species, sample type, gene symbol, modified peptides and/or modification sites, site mapping methods and literature references) is provided. To solve the heterogeneity among the data collected from different sources, the sequence identity of these reported O-GlcNAc peptides are mapped to the UniProtKB protein entries. To our knowledge, O-GlcNAcAtlas is a highly comprehensive and rigorously curated database encapsulating all O-GlcNAc sites and proteins identified in the past 35 years. We expect that O-GlcNAcAtlas will be a useful resource to facilitate O-GlcNAc studies and computational analyses of protein O-GlcNAcylation. The public version of the web interface to the O-GlcNAcAtlas can be found at http://oglcnac.org/.
Sub-Saharan African information potential to unveil adaptations to infectious disease
Authors: Pedro Nicole , Pinto Ricardo J , Cavadas Bruno , Pereira Luisa 
Published: January 2021

Abstract
Sub-Saharan Africa is the most promising region of the world to conduct high-throughput studies to unveil adaptations to infectious diseases due to several reasons, namely, the longest evolving time-depth in the Homo sapiens phylogenetic tree (at least two-third older than any other worldwide region); the continuous burden of infectious diseases (still number one in health/life threat); and the coexistence of populations practising diverse subsistence modes (nomadic or seminomadic hunter-gatherers and agropastoralists, and sedentary agriculturalists, small urban and megacity groups). In this review, we will present the most up-to-date results that shed light on three main hypotheses related with this adaptation. One is the hypothesis of coevolution between host and pathogen, given enough time for the establishment of this highly dynamic relationship. The second hypothesis enunciates that the agricultural transition was responsible for the increase of the infectious disease burden, due to the huge expansion of the sedentary human population and the cohabitation with domesticates as main reservoirs of pathogens. The third hypothesis states that the boosting of our immune system against pathogens by past selection may have resulted in maladaptation of the developed hygienic societies, leading to an increase of allergic, inflammatory and autoimmune disorders. Further work will enlighten the biological mechanisms behind these main adaptations, which can be insightful for translation into diagnosis, prognosis and treatment interventions.
Occupational exposure to respirable crystalline silica and risk of autoimmune rheumatic diseases: a nationwide cohort study
Authors: Boudigaard Signe Hjuler , Schlünssen Vivi , Vestergaard Jesper Medom , Søndergaard Klaus , Torén Kjell , Peters Susan , Kromhout Hans , Kolstad Henrik A 
Published: January 2021

Abstract

Background
Exposure to respirable crystalline silica is suggested to increase the risk of autoimmune rheumatic diseases. We examined the association between respirable crystalline silica exposure and systemic sclerosis, rheumatoid arthritis, systemic lupus erythematosus and small vessel vasculitis.

Methods
In a cohort study of the total Danish working population, we included 1 541 505 male and 1 470 769 female workers followed since entering the labour market 1979–2015. Each worker was annually assigned a level of respirable crystalline silica exposure estimated with a quantitative job exposure matrix. We identified cases of autoimmune rheumatic diseases in a national patient register and examined sex-specific exposure-response relations by cumulative exposure and other exposure metrics.

Results
We identified 4673 male and 12 268 female cases. Adjusted for age and calendar year, men exposed to high levels of respirable crystalline silica compared with non-exposed showed increased incidence rate ratio (IRR) for the four diseases combined of 1.53 [95% confidence interval (CI): 1.39–1.69], for systemic sclerosis of 1.62 (1.08–2.44) and rheumatoid arthritis of 1.57 (1.41–1.75). The overall risk increased with increasing cumulative exposure attained since entering the workforce [IRR: 1.07 (1.05–1.09) per 50 µg/m3-years]. Female workers were less exposed to respirable crystalline silica, but showed comparable risk patterns with overall increased risk with increasing cumulative exposure [IRR: 1.04 (0.99–1.10) per 50 µg/m3-years].

Conclusions
This study shows an exposure-dependent association between occupational exposure to respirable crystalline silica and autoimmune rheumatic diseases and thus suggests causal effects, most evident for systemic sclerosis and rheumatoid arthritis.
Moving toward a sociotechnical systems approach to continuous health information technology design: the path forward for improving electronic health record usability and reducing clinician burnout
Authors: Carayon Pascale , Salwei Megan E 
Published: January 2021

Abstract
Based on our analysis of descriptions provided by four EHR vendors on their EHR usability efforts, we provide three recommendations aimed at improving the usability of health information technology and reducing clinician burnout. First, EHR vendors need to dedicate increased attention to the design of the entire sociotechnical (work) system, including the EHR technology and its usability as well as the interactions of the technology with other system elements. Second, EHR vendors need to deepen and broaden their understanding of the work of clinicians and care teams by using diverse and mixed method. Third, in collaboration with health care organizations, EHR vendors should engage in cycles of continuous design and learning in order to improve the usability of health IT.
Ambulatory physicians’ electronic health record self-efficacy
Authors: Hellems Martha Ann 
Published: January 2021

Abstract
Ambulatory providers were administered an EHR skills self-assessment survey to assess their confidence in learning about and using the electronic health record (EHR). Seventy-one providers participated. Only 35% of respondents felt that they had strong EHR skills, 92% felt confident that they could learn new skills, and 90% felt they could improve with practice. Forty-five percent of faculty physicians felt confident that they could use the EHR in a time-efficient manner and 52% felt could keep up with advances but 16% felt apprehensive about using the EHR. Ninety-four percent of faculty would welcome opportunities to learn more. These results suggest that most providers view using the EHR as a clinical skill they can master with training and practice and that physicians may be engaged by EHR training programs that focus on the use of the EHR as a clinical skill. This work has informed new training programs at our institution.
Spatiotemporal variations in fine-scale habitat use of the world’s second largest population of humpback dolphins
Authors: Liu Mingming , Lin Mingli , Dong Lijun , Zhang Peijun , Li Songhai 
Published: January 2021

AbstractWe assessed habitat use by the population of Indo-Pacific humpback dolphin, Sousa chinensis, in the waters off Zhanjiang, China, by performing boat-based surveys between 2013 and 2018. In total, we gathered 253 sightings of humpback dolphins. To assess habitat use of humpback dolphins within the study area, we measured two spatial metrics at each sighting site: WDT (tide-calibrated water-depth) and DS (distance to the nearest shore). Results showed that dolphins mainly were observed in shallow (WDT: 8.46 ± 5.13 m, mean ± SD) and inshore (DS: 2.17 ± 2.14 km) waters. Their preference of inhabiting shallow waters was more apparent during the wet season (April–September) than during the dry season (October–March); however, they were encountered in waters much closer to shore during the dry season than the wet season. By weighting survey effort, our sighting density maps further confirmed that humpback dolphins changed their habitat use between wet and dry seasons. Such spatiotemporal variations in dolphin habitat use might be associated with spatiotemporal movements of their prey. Our findings provide insights into variations in fine-scale habitat use of inshore apex predators, and also assist to designate proper conservation measures for these vulnerable animals.