A new conception of the shoot of higher plants

According to the classical model, the “shoot” consists only of the categories “caulome” (“stem” sensu lato) and “phyllome” (“leaf” sensu lato), (and “root” in cases of “adventitious” root formation). If lateral shoots are present, their position is axillary. Consequently, caulome as well as phyllome are inserted on the caulome and only on the caulome. This classical model of the shoot has two disadvantages of great consequence: (1) Intermediate organs cannot be accepted as such, but have to be interpreted (i.e. categorized) as either caulome or phyllome (or root) by distortion of the actual similarity. (2) Certain positional changes of organs cannot be accepted as such, but have to be “explained” by congenital fusion. The new conception of the shoot will have the advantages of the classical model but not its disadvantages. Hence, the shoot may consist of the following parts: (main and lateral) shoot, caulome, phyllome, root, emergence, and structures intermediate between (i.e. partially homologous to) any of the preceding. Thus, the five categories of the classical model, namely “shoot”, “caulome”, “phyllome”, “root” and “emergence” are no longer mutually exclusive; they may merge into each other due to an actual or potential continuum. Intermediate organs are therefore accepted as such; for example, an organ may be characterized as an intermediate form between a caulome and a phyllome. Besides intermediate forms, all changes in position are accepted as such. Hence, the following positional relations are possible: caulome and phyllome may be inserted on the caulome, caulome and phyllome may be inserted on the phyllome; roots may be inserted on caulome or phyllome; intermediate forms may be inserted on the caulome, phyllome, or other intermediate forms. Consequences of the new conception for morphological research are pointed out, especially for homologization, evolutionary considerations, and the direction in which research progresses.     

Issues in stem cell plasticity

Experimental biology and medicine work with stem cells more than twenty years. The method discovered for in vitro culture of human embryonal stem cells acquired at abortions or from?surplus” embryos left from in vitro fertilization, evoked immediately ideas on the posibility to aim development and differentiation of these cells at regeneration of damaged tissues. Recently, several surprising observations proved that even tissue‐specific (multipotent) stem cells are capable, under suitable conditions of producing a while spectrum of cell types, regardless, whether these tissues are derived from the same germ layer or not. This ability is frequently called stem cell plasticity but other authors also use different names ‐?non‐orthodox differentiation” or?transdifferentiation”. In this paper we wish to raise several important questions and problems related to this theme. Let us remind some of them: Is it possible to force cells of one‐type tissue to lool and act as cells of another tissue? Are these changes netural? Could these trans‐formations be used to treat diseases? What about the bioethic issue? However, the most serious task “still remains to be soloved ‐ how to detect, harvestand culture stem cells for therapy of certain diseases”.     

Mouse ES cells maintained in different pluripotency-promoting conditions differ in their neural differentiation propensity

Prior to differentiation, embryonic stem (ES) cells in culture are maintained in a so-called “undifferentiated” state, allowing derivation of multiple downstream cell lineages when induced in a directed manner, which in turn grants these cells their “pluripotent” state. The current work is based on a simple observation that the initial culture condition for maintaining mouse ES cells in an “undifferentiated” state does impact on the differentiation propensity of these cells, in this case to a neuronal fate. We point out the importance in judging the “pluripotency” of a given stem cell culture, as this clearly demonstrated that the “undifferentiated” state of these cells is not necessarily a “pluripotent” state, even for a widely used mouse ES cell line. We partly attribute this difference in the initial value of ES cells to the naïve-to-primed status of pluripotency, which in turn may affect early events of the differentiation in vitro.     

Beyond reified categories: multidimensional identifications among ‘black’ and ‘Indian’ groups in Columbia and Mexico

Analyses of multicultural state-dictated social categories are often governed by those same categories, even while they deconstruct them. Nonetheless, these categories are often used in public spheres such as national imaginary or ethno-political activism. Taking a different point of departure, that of representations rather than the categories themselves, the aim of our paper is to understand the modes of classification that are relevant among four populations in Colombia and Mexico who would, a priori, be categorized as ‘black’ or ‘Indian’. The daily reality of these groups indicates other possible internal, sometimes even intersecting, kinds of categorizations, which, far from naturalizing the ‘Indian’ and ‘black’ categories, in fact reveal place-based social identifications. These identifications seem closer to the everyday lives and practices of the people in question, and underscore the local conceptions of their presence and agency in a given spot.     

Anthropomorphic effigy vessels from Chupicuaro,Mexico*

The subjectivity of the anthropologist is grounded in the historical and ideological worlds in which he is positioned. The author finds the basis of his comparison of Australian and Sinhalese Buddhist nationalisms in the Australian cultural context, which leads him to a particular construction of the Sinhalese “otherness”. The Australian egalitarian nationalism and the Sinhalese Buddhist hierarchical nationalism are traced as ideologies through a range of practises, showing differing relationships between nation and state. Both nationalisms, the author argues, are to be understood as equally “modern” .     

Mapping of spatiotemporal distribution of Tibraca limbativentris Stal (Hem.: Pentatomidae) in flooded rice crop in Southern Brazil

The rice stem bug, Tibraca limbativentris Stal (Hem.: Pentatomidae), is one of the main insect pests in Brazilian rice crops. Knowledge of its spatiotemporal distribution can support the development of an effective sampling system and improve IPM strategies. This study aimed to map the spatiotemporal distribution of rice stem bug in flooded rice crop in Southern Brazil. Flooded rice crop was scouted for two seasons to estimate insect densities. Four occurrence categories were observed: no insect, only adults, only nymphs, and both phases. The relationship between phenological stages and insect categories was established. Interpolation (mapping) of occurrence categories of T. limbativentris was performed by multiquadric equations. In two seasons during the rice cycle, the results indicate that rice stem bug “adults” were the most abundant category until the mid-vegetative phase of the rice; “nymphs” were the most abundant from the end of vegetative phase; “adults + nymphs” occurred from the beginning of reproductive phase; there were no rice stem bugs in more than 66% of the area, as they were most concentrated near the edge of the crop. The information presented here provides further knowledge about T. limbativentris spatiotemporal dynamics that can be applied to improve IPM strategies, such as developing sampling plans and localized control measures at the edge of rice fields.     

“Making coin” and the networker: Masculine self‐making in the Australian professional managerial class

In this article I unpack the labour of “networking” to understand the changes in sociality and worker identity that have occurred in the Australian professional managerial class workforce under post‐Fordism. Drawing on fieldwork undertaken at the interface of the pubic service and private consultancy firms in Canberra, I break from dominant readings of intimacy in post‐Fordism which preference either a downwards imposition of “ways of being” from capital to worker, or a reactive self‐regulation in line with objective external structures. Networking, I argue, is as much about being recognised as patron as it is about any tangible economic benefits. The intimate relations and self‐fashioning of networking constitute attempts to embody particular classed, sexualised, gendered fantasies of the figure of “the networker” in post‐Fordist Australian business culture. This interpretation does not necessitate overlooking the tangible results of networking, and I discuss too, how masculine fantasy structures the topography of workplaces.     

Clonal sublines of rat neurotumor RT4 and cell differentiation: II. A conversion coupling of tumorigenicity and a glial property

RT4 is a neurotumor induced by ethylnitrosourea injection of a newborn BDIX rat. We demonstrated previously that heterogeneity in early cultures of RT4 tumor cells can be regularly reproduced in cultures of clonal stem cells (cell type conversion). Our previous studies included morphology, differentiation of neural properties, and chromosome number of “tumor-derived” and “stem cell-derived” differentiated cells. In this paper, these two sets of differentiated cells were examined further for three additional parameters, all of which are related to malignancy. The stem cell (AC) and one type of differentiated cell (D) cause tumors when subcutaneously injected into syngeneic animals, while the other two types (B and E) do not. The amounts of a 250,000 molecular weight cell surface protein, which is probably equivalent to LETS protein (large external transformation-sensitive protein) of hamster and mouse, and the levels of plasminogen activator were examined as possible markers of malignancy. As anticipated, nontumorigenic cells generally have a large amount of the 250,000 molecular weight cell surface protein and are low in plasminogen activator activities, whereas the reverse is true for tumorigenic cells. This supports the idea that B and E cells are nontumorigenic revertants. The cell type conversion phenomenon of RT4 neurotumor and the differentiation of mouse teratoma and myeloid leukemic cells share a number of similarities, but differ in that differentiated RT4 cells can propagate in vitro even after loss of tumorigenicity. The concomitant expression of tumorigenicity and the S100 protein production of the D cell, or of nontumorigenicity and B and E cell differentiation upon the conversion of the stem cell, may suggest a regulational coupling between the tumorigenicity and the expression of a glial protein (S100 protein) in D cells.     

Possible demonstration of multipotential nature of embryonic neural retina by clonal cell culture.

The possible multipotential nature of the neural retina of early chick embryos was examined by the technique of clonal cell culture. Cultures were prepared from cells dissociated from freshly excised neural retinas of 3.5-day-old chick embryos or from cells harvested from primary highdensity cultures. The following four colony types were obtained: colonies differentiating into “lentoid bodies”; colonies with pigment cells; colonies with both “lentoid bodies” and pigment cells; and colonies comprised entirely of unidentifiable cells. Neuronal differentiation occurred frequently in the early stages of culture (up to about 10 days). In some of these neuronal colonies, “lentoid bodies” and, rarely, both “lentoid bodies” and pigment cells differentiated after a further culture period of up to 30 days. Secondary colonies established from primary colonies after 9–10 days demonstrated that these original colonies fell into four different categories: those giving rise to secondary colonies containing only “lentoid bodies,” those giving rise to pigmented colonies only, those developing both lentoid and pigmented colonies, and finally those which gave rise to secondary colonies of all three types, lentoid, pigmented, and mixed colonies. When primary pigmented colonies were recloned at about 30 days after inoculation, the differentiated pigment cells transdifferentiated into lens. Whether multispecific colonies were really of clonal origin or not is discussed. The possible presence of a multipotent progenitor cell able to give rise to multispecific clones in the neural retina of 3.5-day-old chick embryos is suggested. A sequence of differentiation starting from multipotent neural retinal cells to be terminated with lens through the differentiation of neuronal and pigment cells is hypothetically proposed.     

Participation of women medical Physicists in European scientific events: The European experience

PurposeThough the number of women scientists is increasing over the years, studies show that they are still under-represented in leadership roles. The purpose of this work is to establish the percentage of women Medical Physicists (wMPs) that have participated in European scientific events and evaluate it as an indication of the current position of women in the field of Medical Physics in Europe and to propose possible ways to encourage their participation.Materials and MethodsData regarding the participants in European scientific events of Medical Physics were collected. The participants were divided into categories according to the program of the events and their gender was identified. The percentage of wMPs in each category was evaluated.ResultsThe participation of wMPs attending courses is greater than 50%. The categories with the greatest participation are “Organizing Committees”, “Chairpersons-Moderators” and “Oral Presentations”. The categories with the lower participation of wMPs are “Scientific Committee”, “Symposiums” and “Invited Speakers”. None of wMPs were represented as “Course Directors”.ConclusionsThe attendance of wMPs in courses is slightly greater than average. However, wMPs do not have an equally important recognition in special invited roles in conferences. They are still under-represented in “Scientific Committees”, “Invited Speakers”, “Symposiums” and “Course directors”. wMPs should be encouraged to participate even more actively in European conferences and the organizing committees should invite more wMPs in special roles. More studies concerning the status of female MPs in each country separately should be encouraged as they will help in understanding the position of wMPS in Europe.     

Reprogramming cell fates: reconciling rarity with robustness

The stunning possibility of “reprogramming” differentiated somatic cells to express a pluripotent stem cell phenotype (iPS, induced pluripotent stem cell) and the “ground state” character of pluripotency reveal fundamental features of cell fate regulation that lie beyond existing paradigms. The rarity of reprogramming events appears to contradict the robustness with which the unfathomably complex phenotype of stem cells can reliably be generated. This apparent paradox, however, is naturally explained by the rugged “epigenetic landscape” with valleys representing “preprogrammed” attractor states that emerge from the dynamical constraints of the gene regulatory network. This article provides a pedagogical primer to the fundamental principles of gene regulatory networks as integrated dynamic systems and reviews recent insights in gene expression noise and fate determination, thereby offering a formal framework that may help us to understand why cell fate reprogramming events are inherently rare and yet so robust.     

Adult stem cells: seing is not being

Recent unexpected observations in adult rodents that stem/progenitor cells located in the bone marrow, but also in other tissues, could, after their transplantation to an irradiated host contribute to the regeneration of damaged organs such as brain, liver, pancreas or muscle, have raised much hope for future therapeutic applications. These data have also initially been interpreted as a proof of a possible transdifferentiation or plasticity of adult stem cells located in these tissues. Additional experiments rigorously analyzed have tempered initial enthusiasm, by showing that if marrow cells do migrate in damaged muscles and liver, their contribution to organ repair is low, and in some cases, explained by cell fusion. Nevertheless, among bone marrow cells, two categories of stem cells now emerge that have a potentially tremendous interest in cell therapy, if we succeed in understanding how to purify, amplify and differentiate these more efficiently and reproducibly.     

The mis-measure of manioc (Manihot esculenta,Euphorbiaceae)

The distinction between “bitter” and “sweet” (toxic and non-toxic) varieties of the cyanide-containing food crop manioc (Manihot esculenta, Euphorbiaceae) has a long tradition in the tropical forest areas of South and Central America where it was first cultivated. Yet this distinction has no taxonomic basis. The levels of cyanogenic glucosides found in manioc varieties not only vary widely, but do not correspond with any other known morphological or ecological feature. Nonetheless, these two “varieties” are commonly reported to have distinct geographical and cultural distributions and each is associated with a particular traditional food complex. This paper reviews the literature regarding the nature, distribution, and traditional uses of manioc varieties and concludes that (1) the geographical and cultural distribution of bitter and sweet varieties of manioc may not be as distinct as has been thought; (2) traditional categories of bitter and sweet manioc may stem more from culturally derived belief systems than from actual known levels of toxicity; and (3) the choice of complex and labor intensive processing methods usually associated with bitter manioc may not be required for detoxification but rather for the derived food products, particularly manioc flour.     

Cross-Sectional Study of Characteristics of Owners and Nonowners Surrendering Cats to Four Australian Animal Shelters

Unwanted cats surrendered to nonhuman animal shelters are generally categorized as either “owned” or “stray.” This classification is misleading because “stray” cats may include many “semiowned” cats, for which people provide care but who are not perceived as being owned. This differentiation is important because effective strategies designed to reduce cat admissions to, and euthanasia rates in, shelters rely on accurate information about cat populations contributing to shelter intake; cat semiowners will likely respond to different strategies than people with no relationship with the cats they surrender. People surrendering cats to four Australian animal shelters were surveyed to identify factors associated with perception of ownership. Many self-classified nonowners had fed the cats they surrendered, often for a considerable period of time. The factor most strongly associated with ownership perception was an increasing association time with the cat. These findings confirm that enduring relationships between surrenderers and cats, consistent with cat semiownership, are common for cats surrendered to Australian animal shelters. This finding should be taken into account when planning education messages and cat population management strategies aimed at reducing cat admissions.     

The effect of inflammatory factors and their inhibitors on the hematopoietic stem cells fate

Inflammatory cytokines exert different effects on hematopoietic stem cells (HSCs), lead to the development of various cell lineages in bone marrow (BM) and are thus a differentiation axis for HSCs. The content used in this article has been obtained by searching PubMed database and Google Scholar search engine of English-language articles (1995–2020) using “Hematopoietic stem cell,” “Inflammatory cytokine,” “Homeostasis,” and “Myelopoiesis.” Inflammatory cytokines are involved in the differentiation and proliferation of hematopoietic progenitors to compensate for cellular death due to inflammation. Since each of these cytokines differentiates HSCs into a specific cell line, the difference in the effect of these cytokines on the fate of HSC progenitors can be predicted. Inhibitors of these cytokines can also control the inflammatory process as well as the cells involved in leukemic conditions. In general, inflammatory signaling can specify the dominant cell line in BM to counteract inflammation and leukemic condition via stimulating or inhibiting hematopoietic progenitors. Therefore, detection of the effects of inflammatory cytokines on the differentiation of HSCs can be an appropriate approach to check inflammatory and leukemic conditions and the suppression of these cytokines by their inhibitors allows for control of homeostasis in stressful conditions.     

Exploiting stem cell therapy: The 3rd meeting of stem cell research Italy

The study of stem cells is one of the most exciting areas of contemporary biomedical research. During the 3rd Joint Meeting of Stem Cell Research Italy (June 2012, Ferrara, Italy), scientists from different multidisciplinary areas explored new frontiers of basic and applied stem cell research with key lectures and oral presentations. There was a public debate on ethics during the opening ceremony, specifically on the limits and potentialities of adult and embryonic stem cells. Some scientists presented basic research data showing evolutionary aspects, which could be of interest in understanding specific biological phenomena. Others focused on “dangerous liaisons” between gene transfer vectors and the human genome. Some speakers provided insight into current stem cell therapies, such as those involving human epithelial stem cells for treatment of skin diseases. Other researchers presented data on close‐to‐therapy findings, such as the use of mesenchymal stem cells in brain repair. Of note, during the meeting, spotlights were focused on major issues that have to be considered for GMP stem cell production for cell therapy. In “Meet the Expert” sessions, specialists presented innovative technologies such as a next‐generation sequencing system. Finally, the meeting provided an excellent opportunity for young scientists to show their findings, and to discuss with each other and with internationally recognized experts. J. Cell. Physiol. 228: 911–914, 2013. © 2012 Wiley Periodicals, Inc.     

Public discourses of stem cell science in Singapore (1997–2010)

In most industrialized countries, policy debates around stem cell science manifest in public discourse. Assuming that a functioning public sphere exists where matters of science policy can be discussed, examination of these discourses can help provide an understanding of how science policies evolve. The aim of this paper is to provide a preliminary analysis of how the public discourses around stem cell science have developed in Singapore. Using a theoretical model of “focused discourse,” our analysis indicates that there have been five distinct phases, marked by discernible shifts that reflect important changes in how biomedical science is funded in Singapore. While our results are preliminary, we argue that public discourses around science policies do exist in Singapore but are limited by a lack of diversity that would be expected in a more heterogeneous public sphere.