Lineage Tracing of Lamellocytes Demonstrates Drosophila Macrophage Plasticity

Leukocyte-like cells called hemocytes have key functions in Drosophila innate immunity. Three hemocyte types occur: plasmatocytes, crystal cells, and lamellocytes. In the absence of qimmune challenge, plasmatocytes are the predominant hemocyte type detected, while crystal cells and lamellocytes are rare. However, upon infestation by parasitic wasps, or in melanotic mutant strains, large numbers of lamellocytes differentiate and encapsulate material recognized as “non-self”. Current models speculate that lamellocytes, plasmatocytes and crystal cells are distinct lineages that arise from a common prohemocyte progenitor. We show here that over-expression of the CoREST-interacting transcription factor Chn in plasmatocytes induces lamellocyte differentiation, both in circulation and in lymph glands. Lamellocyte increases are accompanied by the extinction of plasmatocyte markers suggesting that plasmatocytes are transformed into lamellocytes. Consistent with this, timed induction of Chn over-expression induces rapid lamellocyte differentiation within 18 hours. We detect double-positive intermediates between plasmatocytes and lamellocytes, and show that isolated plasmatocytes can be triggered to differentiate into lamellocytes in vitro, either in response to Chn over-expression, or following activation of the JAK/STAT pathway. Finally, we have marked plasmatocytes and show by lineage tracing that these differentiate into lamellocytes in response to the Drosophila parasite model Leptopilina boulardi. Taken together, our data suggest that lamellocytes arise from plasmatocytes and that plasmatocytes may be inherently plastic, possessing the ability to differentiate further into lamellocytes upon appropriate challenge

Genome-wide mapping targets of the metazoan chromatin remodeling factor NURF reveals nucleosome remodeling at enhancers, core promoters and gene insulators

NURF is a conserved higher eukaryotic ISWI-containing chromatin remodeling complex that catalyzes ATP-dependent nucleosome sliding. By sliding nucleosomes, NURF is able to alter chromatin dynamics to control transcription and genome organization. Previous biochemical and genetic analysis of the specificity-subunit of Drosophila NURF (Nurf301/Enhancer of Bithorax (E(bx)) has defined NURF as a critical regulator of homeotic, heat-shock and steroid-responsive gene transcription. It has been speculated that NURF controls pathway specific transcription by co-operating with sequence-specific transcription factors to remodel chromatin at dedicated enhancers. However, conclusive in vivo demonstration of this is lacking and precise regulatory elements targeted by NURF are poorly defined. To address this, we have generated a comprehensive map of in vivo NURF activity, using MNase-sequencing to determine at base pair resolution NURF target nucleosomes, and ChIP-sequencing to define sites of NURF recruitment. Our data show that, besides anticipated roles at enhancers, NURF interacts physically and functionally with the TRF2/DREF basal transcription factor to organize nucleosomes downstream of active promoters. Moreover, we detect NURF remodeling and recruitment at distal insulator sites, where NURF functionally interacts with and co-localizes with DREF and insulator proteins including CP190 to establish nucleosome-depleted domains. This insulator function of NURF is most apparent at subclasses of insulators that mark the boundaries of chromatin domains, where multiple insulator proteins co-associate. By visualizing the complete repertoire of in vivo NURF chromatin targets, our data provide new insights into how chromatin remodeling can control genome organization and regulatory interactions

A wake-up call: Equity, inequality and Covid-19 emergency remote teaching and learning

Produced from experiences at the outset of the intense times when Covid-19 lockdown restrictions began in March 2020, this collaborative paper offers the collective reflections and analysis of a group of teaching and learning and Higher Education (HE) scholars from a diverse 15 of the 26 South African public universities. In the form of a theorised narrative insistent on foregrounding personal voices, it presents a snapshot of the pandemic addressing the following question: what does the ‘pivot online’to Emergency Remote Teaching and Learning (ERTL), forced into urgent existence by the Covid-19 pandemic, mean for equity considerations in teaching and learning in HE? Drawing on the work of Therborn (2009: 20–32; 2012: 579–589; 2013; 2020) the reflections consider the forms of inequality-vital, resource and existential-exposed in higher education. Drawing on the work of Tronto (1993; 2015; White and Tronto 2004) the paper shows the networks of care which were formed as a counter to the systemic failures of the sector at the onset of the pandemic

Multiple Geographic Origins of Commensalism and Complex Dispersal History of Black Rats

The Black Rat (Rattus rattus) spread out of Asia to become one of the world's worst agricultural and urban pests, and a reservoir or vector of numerous zoonotic diseases, including the devastating plague. Despite the global scale and inestimable cost of their impacts on both human livelihoods and natural ecosystems, little is known of the global genetic diversity of Black Rats, the timing and directions of their historical dispersals, and the risks associated with contemporary movements. We surveyed mitochondrial DNA of Black Rats collected across their global range as a first step towards obtaining an historical genetic perspective on this socioeconomically important group of rodents. We found a strong phylogeographic pattern with well-differentiated lineages of Black Rats native to South Asia, the Himalayan region, southern Indochina, and northern Indochina to East Asia, and a diversification that probably commenced in the early Middle Pleistocene. We also identified two other currently recognised species of Rattus as potential derivatives of a paraphyletic R. rattus. Three of the four phylogenetic lineage units within R. rattus show clear genetic signatures of major population expansion in prehistoric times, and the distribution of particular haplogroups mirrors archaeologically and historically documented patterns of human dispersal and trade. Commensalism clearly arose multiple times in R. rattus and in widely separated geographic regions, and this may account for apparent regionalism in their associated pathogens. Our findings represent an important step towards deeper understanding the complex and influential relationship that has developed between Black Rats and humans, and invite a thorough re-examination of host-pathogen associations among Black Rats

Die verwitterten Falten seines Gesichts: eine performative Reflektion über Nelson Mandela, das Selbst und den Aufruf zur (Zurück-) Bildung von "Rassen"

On the occasion of the first anniversary of the death of Nelson Rolihlahla MANDELA, this self-exploratory narrative study utilizes a Butlerian performative theoretical framework to both uncover discursively regulated social practices as generative of raced identity ensconced in belonging, and the undoing of such identity through the redeployment of social practices predicated instead on a Weltanschauung of becoming. While the accountable subject of autoethnographic work is concomitantly problematized, fluid subjectivity is itself demonstrated as crucial to historical accountability. A resultant appeal for white South Africans to actively begin the work of defamiliarizing themselves with the sanitized dominant popular culture representation of the peace icon, this research ultimately calls for new existential reflection upon the face of Nelson MANDELA so as to begin uncovering its deeper historical significance, contemporary relevance, and the future ethical imperative it demands of those who come from a liminal position of, as J.M. COETZEE once wrote, "no longer European, not yet African" (1988, p.11). In short, it is argued that white South Africans need to move from a condition of belonging predicated on raced identity to one of transracial—and even interracial—African becoming.URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs150223Con ocasión del primer aniversario de la muerte de Nelson Rolihlahla MANDELA, esta narrativa autoexploratoria utiliza un marco teórico performativo BUTLERiano con el fin, tanto de develar prácticas sociales discursivamente reguladas como generadoras de una identidad racial enquistada en el pertenecer, como de deshacer dicha identidad racial mediante el despliegue de prácticas sociales predicadas en cambio en una cosmovisión del devenir.Mientras que el sujeto que rinde cuentas en el trabajo autoetnográfico es concomitantemente problematizado, se demuestra que la subjetividad fluída ocupa un lugar igualmente crucial en las responsabilidades históricas. La proclama resultante a los sudafricanos blancos, es a iniciar activamente el trabajo de desfamiliarizarse de una dominante y saneada representación en la cultura popular del ícono de la paz. En el fondo, esta investigación hace un llamado a una nueva reflexión existencial acerca del rostro de Nelson MANDELA con el fin de develar su significancia histórica más profunda, su relevancia contemporánea, el imperativo ético que demanda a futuro de aquellos provenientes de una posición liminal: en palabras de J.M. COETZEE, "europeo ya no, africano no todavía". En resumen, es argumentado que los sudafricanos blancos necesitan moverse de una condición en la que pertenecer es predicado sobre una identidad racial, hacia una identidad transracial – aún interracial – del devenir africano.URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs150223Die hier vorliegende, selbstreflexive narrative Studie wurde anlässlich des ersten Jahrestages des Todes von Nelson Rolihlahla MANDELA verfasst. Sie deckt mithilfe der performativen Theorie von BUTLER auf, dass diskursiv geregelte, soziale Praktiken fruchtbar für die Bildung einer Rassenidentität sind, die sich in Zugehörigkeit gründet, wobei sie gleichzeitig auch das Annullieren einer solchen Identität durch eine Umgruppierung von Sozialpraktiken aufzeigt, die stattdessen auf einer Weltanschauung des Werdens fußen. Eine fluide Subjektivität wird als ausschlaggebend für die historische Darstellung des Selbst beschrieben, während auch das verantwortliche Subjekt der autoethnografischen Arbeit hier problematisiert wird.Die Studie stellt einen sich daraus ergebenden Aufruf für weiße Südafrikaner/innen dar, sich aktiv von einer abgeschwächten, dominanten Repräsentation der Friedensikone in der Populärkultur zu entfernen und fordert eine neue existenzielle Reflektion der Erscheinung von Nelson MANDELA, sodass ihre tiefere, historische Bedeutung, gegenwärtige Relevanz und zukünftige ethische Signifikanz aufgedeckt werden können, die sie von denen einfordert, die von einer Schwellenposition herkommen, wie z.B. J.M. COETZEE (1988, S.11) sie benannte: "Nicht mehr Europa, noch nicht Afrika". Somit wird hier vorgeschlagen, dass sich weiße Südafrikaner/innen von einem Zustand der Zugehörigkeit, der auf eine Rassenidentität gründet, wegbewegen müssen hin zu einer gemischtrassischen afrikanischen Identität des Werdens.URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs15022

The weathered corrugations of his face: a performative reflection on Nelson Mandela, self, and the call for racial (un)becoming

On the occasion of the first anniversary of the death of Nelson Rolihlahla Mandela, this self-exploratory narrative study utilizes a Butlerian performative theoretical framework to both uncover discursively regulated social practices as generative of raced identity ensconced in belonging, and the undoing of such identity through the redeployment of social practices predicated instead on a Weltanschauung of becoming. While the accountable subject of autoethnographic work is concomitantly problematized, fluid subjectivity is itself demonstrated as crucial to historical accountability. A resultant appeal for white South Africans to actively begin the work of defamiliarizing themselves with the sanitized dominant popular culture representation of the peace icon, this research ultimately calls for new existential reflection upon the face of Nelson Mandela so as to begin uncovering its deeper historical significance, contemporary relevance, and the future ethical imperative it demands of those who come from a liminal position of, as J.M. Coetzee once wrote, "no longer European, not yet African" (1988, p.11). In short, it is argued that white South Africans need to move from a condition of belonging predicated on raced identity to one of transracial -and even interracial- African becoming. (author's abstract)Die hier vorliegende, selbstreflexive narrative Studie wurde anlässlich des ersten Jahrestages des Todes von Nelson Rolihlahla Mandela verfasst. Sie deckt mithilfe der performativen Theorie von Butler auf, dass diskursiv geregelte, soziale Praktiken fruchtbar für die Bildung einer Rassenidentität sind, die sich in Zugehörigkeit gründet, wobei sie gleichzeitig auch das Annullieren einer solchen Identität durch eine Umgruppierung von Sozialpraktiken aufzeigt, die stattdessen auf einer Weltanschauung des Werdens fußen. Eine fluide Subjektivität wird als ausschlaggebend für die historische Darstellung des Selbst beschrieben, während auch das verantwortliche Subjekt der autoethnografischen Arbeit hier problematisiert wird. Die Studie stellt einen sich daraus ergebenden Aufruf für weiße Südafrikaner/innen dar, sich aktiv von einer abgeschwächten, dominanten Repräsentation der Friedensikone in der Populärkultur zu entfernen und fordert eine neue existenzielle Reflektion der Erscheinung von Nelson Mandela, sodass ihre tiefere, historische Bedeutung, gegenwärtige Relevanz und zukünftige ethische Signifikanz aufgedeckt werden können, die sie von denen einfordert, die von einer Schwellenposition herkommen, wie z.B. J.M. Coetzee (1988, S.11) sie benannte: "Nicht mehr Europa, noch nicht Afrika". Somit wird hier vorgeschlagen, dass sich weiße Südafrikaner/innen von einem Zustand der Zugehörigkeit, der auf eine Rassenidentität gründet, wegbewegen müssen hin zu einer gemischtrassischen afrikanischen Identität des Werdens. (Autorenreferat

The Weathered Corrugations of His Face: A Performative Reflection on Nelson Mandela, Self, and the Call for Racial (Un)Becoming

On the occasion of the first anniversary of the death of Nelson Rolihlahla MANDELA, this self-exploratory narrative study utilizes a Butlerian performative theoretical framework to both uncover discursively regulated social practices as generative of raced identity ensconced in belonging, and the undoing of such identity through the redeployment of social practices predicated instead on a Weltanschauung of becoming. While the accountable subject of autoethnographic work is concomitantly problematized, fluid subjectivity is itself demonstrated as crucial to historical accountability. A resultant appeal for white South Africans to actively begin the work of defamiliarizing themselves with the sanitized dominant popular culture representation of the peace icon, this research ultimately calls for new existential reflection upon the face of Nelson MANDELA so as to begin uncovering its deeper historical significance, contemporary relevance, and the future ethical imperative it demands of those who come from a liminal position of, as J.M. COETZEE once wrote, "no longer European, not yet African" (1988, p.11). In short, it is argued that white South Africans need to move from a condition of belonging predicated on raced identity to one of transracial—and even interracial—African becoming. URN: http://nbn-resolving.de/urn:nbn:de:0114-fqs15022