A Subantarctic rare gastropod reveals a new type of spawn among heterobranchs

2020 ◽  
Vol 190 (2) ◽  
pp. 508-517
Author(s):  
Javier Di Luca ◽  
Pablo E Penchaszadeh ◽  
Guido Pastorino
Keyword(s):  
Developmental Stages ◽  
Average Diameter ◽  
Additional Source ◽  
Capsule Wall ◽  
Egg Capsules ◽  
Adaptive Value ◽  
New Type ◽  
Taxonomic Implications ◽  
Level Identification

Abstract Spawn and specimens of Toledonia biplicata comb. nov. were collected from Burdwood Bank during March 2013. Species-level identification was derived from radular, shell and spawn characters. A low number of eggs laid per spawn (one to three), absence of an external gelatinous mass and a considerably thickened capsule wall (~50 µm) constitute a unique combination of spawn characters among heterobranchs. Egg capsules are ovoid in shape and measure 600–763 × 450–656 µm. They are filled with albuminous liquid, allowing complete intracapsular development of a single embryo. The developmental stages recognized are uncleaved eggs (153 µm in average diameter), veliger stages (279–378 µm in maximal length) and prehatchling juveniles (442–609 µm). Toledonia biplicata increases its volume 40-fold during its intracapsular development, whereas other comparable cephalaspids increase ≤ 4-fold. The role of the capsule wall as protection and an additional source of food is discussed. The adaptive value of these characters in relationship to the environmental conditions of the Magellanic region is discussed. A comparison with the spawn of other cephalaspids, nudibranchs and pleurobranchids is conducted, and the taxonomic implications are discussed. This is the first description of the spawn and developmental stages of a representative of the genus Toledonia.

scholarly journals Crayfish hemocytes develop along the granular cell lineage

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fang Li ◽  
Zaichao Zheng ◽  
Hongyu Li ◽  
Rongrong Fu ◽  
Limei Xu ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Cell Lineage ◽  
Granular Cell ◽  
Marker Genes ◽  
Hematopoietic Tissue ◽  
Differentiated Cells ◽  
Stage Of Development ◽  
Almost All ◽  
Relationship Of

AbstractDespite the central role of hemocytes in crustacean immunity, the process of hemocyte differentiation and maturation remains unclear. In some decapods, it has been proposed that the two main types of hemocytes, granular cells (GCs) and semigranular cells (SGCs), differentiate along separate lineages. However, our current findings challenge this model. By tracking newly produced hemocytes and transplanted cells, we demonstrate that almost all the circulating hemocytes of crayfish belong to the GC lineage. SGCs and GCs may represent hemocytes of different developmental stages rather than two types of fully differentiated cells. Hemocyte precursors produced by progenitor cells differentiate in the hematopoietic tissue (HPT) for 3 ~ 4 days. Immature hemocytes are released from HPT in the form of SGCs and take 1 ~ 3 months to mature in the circulation. GCs represent the terminal stage of development. They can survive for as long as 2 months. The changes in the expression pattern of marker genes during GC differentiation support our conclusions. Further analysis of hemocyte phagocytosis indicates the existence of functionally different subpopulations. These findings may reshape our understanding of crustacean hematopoiesis and may lead to reconsideration of the roles and relationship of circulating hemocytes.

Toward a theory on workplaces for smart workers

Facilities ◽  
2019 ◽  
Vol 38 (3/4) ◽  
pp. 298-315
Author(s):  
Luisa Errichiello ◽  
Tommasina Pianese
Keyword(s):  
Web Sites ◽  
Participant Observation ◽  
Secondary Data ◽  
Primary Data ◽  
Innovative Design ◽  
Content Type ◽  
New Type ◽  
Smart Working ◽  
Research Propositions

Purpose The purpose of this paper is to identify the main features of smart work centers (SWCs) and show how these innovative offices would support the implementation of smart working and related changes in workspaces (“bricks”), technologies (“bytes”) and organizational practices (“behaviors”). Design/methodology/approach In this study, scientific literature is combined with white papers and business reports and visits to 14 workplaces, including offices designed as SWCs, co-working spaces, one telecenter, one accelerator and one fab lab. Primary data were collected through interviews with managers and users and non-participant observation, whereas secondary data included web-sites, brochures, presentations, press releases and official documents. Findings The authors developed research propositions about how the design of spaces and the availability of technology within SWCs would support the “bricks” and “bytes” levers of smart working. More importantly, the authors assumed that this new type of workplace would sustain changes in employees’ behaviors and managers’ practices, thus helping to overcome several challenges traditionally associated with remote working. Research limitations/implications The exploratory nature of the research only provides preliminary information about the role of SWCs within smart working programs. Additional qualitative and quantitative empirical investigation is required. Practical implications This study provides valuable knowledge about how the design of corporate offices can be leveraged to sustain the implementation of smart working. Originality/value This study advances knowledge on workplaces by focusing on an innovative design of traditional offices (SWC). It also lays the foundations for future investigation aimed at testing the developed propositions.

scholarly journals Epigenetic transgenerational inheritance, Gametogenesis and Germline Development

2021 ◽  
Author(s):  
Millissia Ben Maamar ◽  
Eric E Nilsson ◽  
Michael K Skinner
Keyword(s):  
Developmental Biology ◽  
Environmental Factors ◽  
Biological System ◽  
Developmental Stages ◽  
Primordial Germ Cell ◽  
Cell Types ◽  
Transgenerational Inheritance ◽  
Germline Development ◽  
Current Review

Abstract One of the most important developing cell types in any biological system is the gamete (sperm and egg). The transmission of phenotypes and optimally adapted physiology to subsequent generations is in large part controlled by gametogenesis. In contrast to genetics, the environment actively regulates epigenetics to impact the physiology and phenotype of cellular and biological systems. The integration of epigenetics and genetics is critical for all developmental biology systems at the cellular and organism level. The current review is focused on the role of epigenetics during gametogenesis for both the spermatogenesis system in the male and oogenesis system in the female. The developmental stages from the initial primordial germ cell through gametogenesis to the mature sperm and egg are presented. How environmental factors can influence the epigenetics of gametogenesis to impact the epigenetic transgenerational inheritance of phenotypic and physiological change in subsequent generations is reviewed.

The Entrepreneurial University: Evidence of the Changing Role of Universities in Modern Russia

2014 ◽  
Vol 28 (4) ◽  
pp. 271-280 ◽  
Author(s):  
Dina Williams ◽  
Alexey Kluev
Keyword(s):  
Entrepreneurial University ◽  
Primary Data ◽  
Strategy Development ◽  
Infrastructure Development ◽  
Innovation Development ◽  
Policy Makers ◽  
Managerial Competencies ◽  
New Type ◽  
Changing Role

This paper examines the evolution of the entrepreneurial function of Russia's leading universities: the study is based on a conceptualization of a university's entrepreneurial development pathway developed by the OECD in 2009. The data on entrepreneurship development were collected in 2012 through a survey of technology transfer and innovation development managers of 18 National Research Universities. The primary data were complemented by desktop analysis of the strategy development documents of the universities surveyed. The results suggest that in the period studied, 2008–2012, a new type of university, the entrepreneurial university, has emerged in Russia. However, these entrepreneurial universities are facing serious challenges in the implementation of an entrepreneurial, innovation-oriented mission due to the lack of managerial competencies and inadequate infrastructure development. The paper has significant theoretical and practical implications in shedding light on the development of the entrepreneurial university in Russia, where the process is still in its infancy. The authors depict a trajectory of entrepreneurial transformation in and barriers to this process that, it is argued, university executives and policy makers should take into consideration.

Improving Juvenile Justice for Females: A Statewide Assessment in California

2002 ◽  
Vol 48 (4) ◽  
pp. 526-552 ◽  
Author(s):  
Barbara Bloom ◽  
Barbara Owen ◽  
Elizabeth Piper Deschenes ◽  
Jill Rosenbaum
Keyword(s):  
Developmental Stages ◽  
State Agencies ◽  
Specific Policy ◽  
Statewide Assessment ◽  
Female Adolescence ◽  
Staffing And Training ◽  
Substance Abuse Education ◽  
Gender Specific ◽  
And Training

This article reports findings from a survey of officials from various California state agencies and a series of interviews and focus groups with female youth and professionals serving this population. The study examined types of services provided, program barriers, and facilitation of change. The findings were used to make gender-specific policy and program recommendations. The authors found that meeting the needs of girls and young women requires specialized staffing and training, particularly in terms of relationship and communication skills, gender differences in delinquency, substance abuse education, the role of abuse, developmental stages of female adolescence, and available programs and appropriate placements and limitations. Effective programming for girls and women should be shaped by and tailored to their real-world situations and problems. In order to do this, a theoretical approach to treatment that is gender-sensitive and that addresses the realities of girls' lives must be developed.

scholarly journals Characterization of the Drosophila protein arginine methyltransferases DART1 and DART4

2004 ◽  
Vol 379 (2) ◽  
pp. 283-289 ◽  
Author(s):  
Marie-Chloé BOULANGER ◽  
Tina Branscombe MIRANDA ◽  
Steven CLARKE ◽  
Marco di FRUSCIO ◽  
Beat SUTER ◽  
...  
Keyword(s):  
Rna Binding ◽  
Developmental Stages ◽  
Rna Binding Proteins ◽  
Genetic System ◽  
Arginine Methylation ◽  
Type I ◽  
Protein Arginine Methyltransferases ◽  
Arginine Residues ◽  
Drosophila Protein

The role of arginine methylation in Drosophila melanogaster is unknown. We identified a family of nine PRMTs (protein arginine methyltransferases) by sequence homology with mammalian arginine methyltransferases, which we have named DART1 to DART9 (Drosophilaarginine methyltransferases 1–9). In keeping with the mammalian PRMT nomenclature, DART1, DART4, DART5 and DART7 are the putative homologues of PRMT1, PRMT4, PRMT5 and PRMT7. Other DART family members have a closer resemblance to PRMT1, but do not have identifiable homologues. All nine genes are expressed in Drosophila at various developmental stages. DART1 and DART4 have arginine methyltransferase activity towards substrates, including histones and RNA-binding proteins. Amino acid analysis of the methylated arginine residues confirmed that both DART1 and DART4 catalyse the formation of asymmetrical dimethylated arginine residues and they are type I arginine methyltransferases. The presence of PRMTs in D. melanogaster suggest that flies are a suitable genetic system to study arginine methylation.

scholarly journals Epigenetic Changes in the Regulation of Nicotiana tabacum Response to Cucumber Mosaic Virus Infection and Symptom Recovery through Single-Base Resolution Methylomes

Viruses ◽  
2018 ◽  
Vol 10 (8) ◽  
pp. 402 ◽  
Author(s):  
Chenguang Wang ◽  
Chaonan Wang ◽  
Wenjie Xu ◽  
Jingze Zou ◽  
Yanhong Qiu ◽  
...  
Keyword(s):  
Immune Response ◽  
Nicotiana Tabacum ◽  
Viral Infection ◽  
Cucumber Mosaic Virus ◽  
Mosaic Virus ◽  
Developmental Stages ◽  
Reduced Representation ◽  
Reduced Representation Bisulfite Sequencing ◽  
Symptom Recovery

Plants have evolved multiple mechanisms to respond to viral infection. These responses have been studied in detail at the level of host immune response and antiviral RNA silencing (RNAi). However, the possibility of epigenetic reprogramming has not been thoroughly investigated. Here, we identified the role of DNA methylation during viral infection and performed reduced representation bisulfite sequencing (RRBS) on tissues of Cucumber mosaic virus (CMV)-infected Nicotiana tabacum at various developmental stages. Differential methylated regions are enriched with CHH sequence contexts, 80% of which are located on the gene body to regulate gene expression in a temporal style. The methylated genes depressed by methyltransferase inhibition largely overlapped with methylated genes in response to viral invasion. Activation in the argonaute protein and depression in methyl donor synthase revealed the important role of dynamic methylation changes in modulating viral clearance and resistance signaling. Methylation-expression relationships were found to be required for the immune response and cellular components are necessary for the proper defense response to infection and symptom recovery.

Some Origins of Nationalism in East Africa

1968 ◽  
Vol 9 (1) ◽  
pp. 119-146 ◽  
Author(s):  
J. M. Lonsdale
Keyword(s):  
Central Government ◽  
Colonial Period ◽  
Political Activity ◽  
Colonial Rule ◽  
Face To Face ◽  
National Movements ◽  
New Type ◽  
First Time ◽  
Official Recognition

This paper attempts to provide a frame of reference for evaluating the role of ordinary rural Africans in national movements, in the belief that scholarly preoccupation with élites will only partially illumine the mainsprings of nationalism. Kenya has been taken as the main field of enquiry, with contrasts and comparisons drawn from Uganda and Tanganyika. The processes of social change are discussed with a view to establishing that by the end of the colonial period one can talk of peasants rather than tribesmen in some of the more progressive areas. This change entailed a decline in the leadership functions of tribal chiefs who were also the official agents of colonial rule, but did not necessarily mean the firm establishment of a new type of rural leadership. The central part of the paper is taken up with an account of the competition between these older and newer leaderships, for official recognition rather than a mass following. A popular following was one of the conditions for such recognition, but neither really achieved this prior to 1945 except in Kikuyuland, and there the newer leaders did not want official recognition. After 1945 the newer leadership, comprising especially traders and officials of marketing co-operatives, seems everywhere to have won a properly representative position, due mainly to the enforced agrarian changes which brought the peasant face to face with the central government, perhaps for the first time. This confrontation, together with the experience of failure in earlier and more local political activity, resulted in a national revolution coalescing from below, co-ordinated rather than instigated by the educated élite.

The encapsular developmental sequence of the mesogastropod Turritella communis (Gastropoda: Turritellidae)

1992 ◽  
Vol 72 (4) ◽  
pp. 783-805 ◽  
Author(s):  
J. J. Kennedy ◽  
B. F. Keegan
Keyword(s):  
Germinal Vesicle ◽  
Average Diameter ◽  
Meiotic Maturation ◽  
Developmental Sequence ◽  
Early Cleavage ◽  
Mantle Tissue ◽  
Cell Stage ◽  
Egg Capsules ◽  
Eupyrene Sperm ◽  
The Right

The development of the lecithotrophic encapsulated larva of the internally-fertilizing, sublittoral gastropod Turritella communis Risso 1826 was documented using scanning electron microscopy and light microscopy. Encapsulated development was completed in 12 days at 15°C in the laboratory. Spawning occurred above ~10°C. Spawn masses consisted of numerous gelatinous egg capsules, each of which contained ~28 eggs, encased in albumen and fertilizing sperm. The eggs had an average diameter of 139 μm. Fertilization was accomplished by unpaired eupyrene sperm and occurred at the germinal vesicle stage. The developmental sequence followed the typical gastropod pattern, but was unique in a number of respects. Polar lobes were produced during meiotic maturation and early cleavage, with an especially large lobe occurring in association with the first cleavage, which was unequal. The blastula developed into a dorso-ventrally flattened placula at the 70-cell stage. Gastrulation occurred through invagination and epiboly acting together, and was uniquely accompanied by the development of ectodermal microvilli measuring ~ 1 μm in length. Extra-embryonic albumen began to be depleted after the development of the microvilli. It is proposed that the ciliated telotrochal cells gave rise to the pair of statocysts. Torsion was additionally observed to be facilitated by the growth of pre-mantle tissue on the right side and retardation of growth on the left side.

Collective in exile: Utilizing terror management theory to understand women’s wailing performance

2017 ◽  
Vol 54 (4) ◽  
pp. 523-539 ◽  
Author(s):  
Tova Gamliel
Keyword(s):  
Death Anxiety ◽  
Terror Management Theory ◽  
Mortality Salience ◽  
Terror Management ◽  
Research Literature ◽  
Community Context ◽  
Management Theory ◽  
Adaptive Value ◽  
Traditional Performance

Although women’s wailing at death rites in various cultures typically amplifies mortality salience, this ritual phenomenon is absent in the research literature on terror management theory (TMT). This study explored Yemenite-Jewish wailing in Israel as an example of how a traditional performance manages death anxiety in a community context. Observations of wailing events and interviews with Yemenite-Jewish wailers and mourners in Israel were analyzed to understand respondents’ perceptions of the experience of wailing as well as the anxiety-oriented psychotherapeutic expertise involved. The findings are discussed to propose an alternative outlook on the intersubjective adaptive value of death anxiety. After describing TMT’s view on the role of culture in coping with death anxiety, I consider the extent to which Yemenite-Jewish wailing is consistent with the premises of TMT.

Sign in / Sign up

Export Citation Format

Share Document