7,166 research outputs found
Time-course analysis of nuclear events during conjugation in the marine ciliate Euplotes vannus and comparison with other ciliates (Protozoa, Ciliophora)
No full textCiliates represent a morphologically and genetically distinct group of single-celled eukaryotes that segregate germline and somatic functions into two types of nuclei and exhibit complex cytogenetic events during the sexual process of conjugation, which is under the control of the so-called ‘mating type systems’. Studying conjugation in ciliates may provide insight lead to major advances into our understanding of the origins and evolution of sex and fertilization. In the present work, we studied in detail the sexual process of conjugation using the model species Euplotes vannus, and compared these nuclear events with those occurring in other ciliates. Our results indicate that in E. vannus: 1) conjugation requires about 75 hours to complete: the longest step is the development of the new macronucleus (ca. 64h), followed by the nuclear division of meiosis I (5h); the mitotic divisions usually take only 2h; 2) there are three prezygotic divisions (mitosis and meiosis I and II), and two of the eight resulting nuclei become pronuclei; 3) after the exchange and fusion of the pronuclei, two postzygotic divisions occur; two of the four products differentiate into the new micronucleus and macronucleus, respectively, and the parental macronucleus degenerates completely; 4) comparison of the nuclear events during conjugation in different ciliates reveals that there are generally three prezygotic divisions while the number of postzygotic divisions is highly variable. These results can serve as reference to investigate the mating type system operating in this species and to analyze genes involved in the different steps of the sexual process
Conjugation in Euplotes raikovi (Protista, Ciliophora): New Insights into Nuclear Events and Macronuclear Development from Micronucleate and Amicronucleate Cells
No full textCiliates form a distinct group of single‐celled eukaryotes that host two types of nuclei (micro and macronucleus) in the same cytoplasm and have a special sexual process known as conjugation, which involves mitosis, meiosis, fertilization, nuclear differentiation, and development. Due to their high species diversity, ciliates have evolved different patterns of nuclear events during conjugation. In the present study, we investigate these events in detail in the marine species Euplotes raikovi. Our results indicate that: (i) conjugation lasts for about 50 hours, the longest stage being the development of the new macronucleus (ca. 36 hours); (ii) there are three prezygotic micronuclear divisions (mitosis and meiosis I and II) and two postzygotic synkaryon divisions; and (iii) a fragment of the parental macronucleus fuses with the new developing macronucleus. In addition, we describe for the first time conjugation in amicronucleate E. raikovi cells. When two amicronucleate cells mate, they separate after about 4 hours without evident nuclear changes; when one amicronucleate cell mates with a micronucleate cell, the micronucleus undergoes regular prezygotic divisions to form migratory and stationary pronuclei, but the two pronuclei fuse in the same cell. In the amicronucleate cell, the parental macronucleus breaks into fragments, which are then recovered to form a new functional macronucleus. These results add new information on the process of conjugation in both micronucleate and amicronucleate Euplotes cells
Characterization of the macronuclear and micronuclear pheromone genes of Euplotes raikovi reveals the origin of the mating type genetic diversity
No full textCiliates produce diffusible, cell-type-specific pheromones to regulate growth and mating. In Euplotes, these signaling molecules belong to species-specific families of disulfide-rich and structurally homologous proteins. Pheromones are co-dominantly expressed by genes in the somatic macronucleus (MAC), whereas their allelic diversity originates from the mating type locus in the germline micronucleus (MIC). During MAC development in sexual process, the MIC-derived diversity of specific alleles is rearranged via macronucleus-destined sequences (MDSs) assembly. While many MAC pheromones are well characterized, their MIC precursors and rearrangement process remain unknown. Here, we identified two MAC pheromone genes (mac-er-13/14) of E. raikovi, and two MIC regions (19 kb in total) containing 10 MDSs that assemble into mac-er-13. These MDSs are separated by internal eliminated sequences (234-3345 bp). The shortest MDSs (9-36 bp) encode the secreted region of pheromone, while longer MDSs (44-419 bp) encode other regions. Considering that the secreted regions show a higher sequence variation and the shorter MDSs have higher probability of alternative processing or imprecise assembly, we hypothesize that the high sequence variability of the macronuclear pheromone genes, which underlies the large number of mating types in E. raikovi, may result from alternative processing or imprecise assembly of these short MDSs
A Conversation with Xianghong Feng, Author of Tourism and Prosperity in Miao Land
No full textIn this installment of Lexington Books\u27 Anthropology of Tourism: Heritage, Mobility and Society Author Conversations, series editor Michael A. Di Giovine talks to anthropologist Xianghong Feng, author of the book, Tourism and Prosperity in Miao Land: Power and Inequality in Rural China. With rich ethnographic detail, Feng focuses on the intersection of tourism development, power and inequality in the southern interior of China. Capital-intensive, elite-driven tourism has reshaped the social and cultural patterns of the ethnic Miao. Although tourism is often touted as able to empower women, lower classes, and minorities, Feng shows that often it reinforces the very power structures that it attempts to equalize
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No full textThis is a curious book. The verso of the title-page says simply "Reprinted from the 1953 edition." From all I can learn, that is true, but that original was printed not by the University Press of the Pacific but by the Foreign Languages Press in Beijing. Indeed, it seems as though this book is a photocopy reprint of that original, and so even the page references in my comment on that book still apply here. These fables are often directly admonitory and/or of a highly political slant. Thus the author writes of skylarks "Poets like these are the true friends of the people" (6). The best of the fables, I believe, are "The Snake and the Rabbit" (42) and "The Original Rat" (61), which may also have the best illustration. Among the most overtly political are those on the imperialist weasel munching a duckling (27) and the imperialist snake against the collective bees (29). Other good fables include "The Hunter and His Wife" (12), "The Lion and the Setting Sun" (15), "The Lion and the Lamb" (34), "The Fox and the Rabbits' Farm" (39), "The Cow and Her Rope" (53), "The Curious Crow" (44), and "The Cow and Her Calf" (54). There is a T of C at the front after the highly political "Publisher's Note." 7½" x 9¼".Feng Hsueh-feng, translated by Gladys Yan
A translation comparison of stray birds between Zheng Zhenduo’s version and Feng Tang’s version : from the perspective of manipulation theory
No full textThis paper employed Lefevere’s Manipulation Theory to explain respectively how
three main factors of Manipulation Theory, namely patronage, ideology and poetics
controlled Zheng Zhenduo’s and Feng Tang’s translation activity of Tagore’s Stray
Birds. And then the paper will analyze their translation strategies by comparing
certain poems in Stray Birds. However, author of this paper did not aim to reconfirm
Lefevere’s Manipulation Theory, but under his theoretical framework, tried to
interpret translation phenomenon from an extra-linguistic perspective.
Through analysis and comparison, the importance of three core elements was
different in those two versions. For Zheng Zhenduo, three main elements shared equal
impacts on his translation. His individual ideology and poetics conformed to
prevailing ideology and poetics in those days, and his patronage also exerted a
positive influence, therefore his Stray Birds received favorable reviews.
In Feng Tang’s case, individual poetics played the most important role. Although his
poetics reflected literary trends to some extent, but that is still not the mainstream in
today’s literary market. The translator’s subjectivity in Feng’s version was clearly
stronger than Zheng’s. For the purpose of literary innovation and commercial interests,
patronage did not manipulate Feng’s translation too much. As a result, Feng Tang’s
Stray Birds was forced to stop sales.
Key words: Zheng Zhenduo; Feng Tang; Stray Birds; Manipulation TheoryMaster of Art
Fables: Feng Hsueh-feng
No full textOnce this book arrived, I thought it a repeat of something I already have. Closer inspection shows that I have a softbound second edition of 1955, while this is the first edition of 1953. Apparently the order of fables changed significantly in the second edition, though there are fifty-one fables here as there. As I mention there, the fables are often directly admonitory and/or of a highly political slant. Thus the author writes of skylarks ”Poets like these are the true friends of the people” (6). The best of the fables, I believe, are ”The Snake and the Rabbit (42) and ”The Original Rat” (61), which may also have the best illustration. Among the most overtly political are those on the imperialist weasel munching a duckling (27) and the imperialist snake against the collective bees (29). Other good fables include ”The Hunter and His Wife” (12), ”The Lion and the Setting Sun” (15), ”The Lion and the Lamb” (34), ”The Fox and the Rabbits' Farm” (39), ”The Cow and Her Rope” (53), ”The Curious Crow” (44), and ”The Cow and Her Calf” (54). There is a T of C at the front.This is a hardbound book (hard cover)Original language: chiStated first editionFeng Hsueh-Feng, translated by Gladys Yan
Timing and characteristics of nuclear events during conjugation and genomic exclusion in Paramecium multimicronucleatum
No full textCiliated protists are ideal material for studying the origin and evolution of sex, because of their nuclear dimorphism (containing both germline micronucleus and somatic macronucleus in the same cytoplasm), special sexual processes (conjugation and autogamy), and high diversity of mating-type systems. However, the study of sexual process is limited to only a few species, due to the difficulties in inducing or observing conjugation. In the present study, we investigate the conjugation process in Paramecium multimicronucleatum: (1) of the three prezygotic divisions, all micronuclei undergo the first two divisions (meiosis I, II), while a variable number of nuclei undergo the third division (mitosis); (2) the synkaryon divides three times after fertilization, giving rise to eight products that differentiate into four macronuclear anlagen and four micronuclei; (3) cells restore the vegetative stage after two successive cell fissions during which the macronuclear anlagen are distributed into daughter cells without division, while micronuclei divide mitotically; (4) the parental macronucleus begins to fragment following the first meiotic division and finally degenerates completely; (5) the entire process takes about 110 h, of which about 85 h are required for macronuclear development. In addition, we describe for the first time the process of genomic exclusion occurring between amicronucleate and micronucleate cells of P. multimicronucleatum, during which the micronucleate cell contributes a pronucleus to the amicronucleate cell, resulting in both exconjugants being homozygotes. These results provide new insights into the diversity of sexual processes and lay an important cytological basis for future in-depth studies of mating systems in ciliates
To comply or not to comply: understanding the discretion in reporting public float and SEC regulations
No full textThis paper documents how firms exercise discretion in defining affiliates and reporting public float in response to SEC regulations. I find that firms with higher expected compliance costs under Section 404 of the Sarbanes-Oxley Act (SOX) of 2002 tend to classify more shares as affiliated and report lower public float. In contrast, firms issuing seasoned equity are less likely to underreport public float, possibly due to favorable regulatory treatment for large issuers. These incentives are weakened when future regulatory changes render float less important.Peer reviewe
[[alternative]]A Study of The Effects of the Traditional concept of Feng-Shui To the modern Engineering Behavior.
No full text[[abstract]]This research discusses about Feng-Shui and its effect to interior design. The study focuses on the related concepts and attitude toward general people. The researcher applies several analyses, including average, standard deviation, and variance analysis to the answers retrieved from subjects participating in the survey of "Relevant Attitude toward Feng-Shui and Engineering Behavior."
The analyses are proceeded in both the overall and separated layers' prospect. The results are as following:
1. To general people, there is no difference between gender and the degree of being influenced by the concept of Feng-Shui.
2. To general people, the cognitive attitude toward Feng-Shui develops when they age.
3. The higher education general people get, the more cognitive attitude toward Feng-Shui they have.
4. The concept of Feng-Shui shows no relevant difference among the Catholics, the Christians, or atheists while it relevantly influences people who believe in the folk religion, Taoism, or Buddhism.
5. People who ask Feng-Shui are relevantly influenced by the concept of Feng-Shui.
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