Dialogizität und sequenzielle Verdichtung in der Forenkommunikation: Editieren als kommunikatives Verfahren

Drawing both on conversation analysis and text linguistics, this article retraces the emergence of a new communicative practice in an online discussion forum: Based on data from an academic learning environment, we demonstrate how peers in a student study group start using the "edit button” which allows them to modify in retrospect not only their own but also other people's posts. This communicative practice of post editing in online discussion forums develops in four stages: It starts out as simple postings of messages on a discussion board. Next, the collocutors make use of the edit button to change their own posts, and, in a dialogical manner that of their discussion partners. Finally, it comes down to a complex form of exchange between the interlocutors who innovatively use the edit button within a single post. By using the edit button in innovative ways the participants bring together sequentially related messages in a single post that are usually spread over multiple posts. We argue that the emergence of this innovative use of the strategy of "sequential compression” (sequenzielle Verdichtung), as we shall call it, may be understood as an answer both to the affordances of asynchronous communication in discussion forums and to the learning situation which is characterized by pressure of time calling for new and innovative strategie

Dialogische Textkompetenz - Routinisiertes Schreiben in studentischer Online-Teamarbeit

Current concepts in writing research primarily focus on monological texts, by which we mean texts that do not demand a reply. But nowadays, dialogical writing - the exchange of messages via e.g. e-mail, text message or internet forum - is increasingly prevalent in private, educational and professional life. We therefore argue that concepts of writing research should also be made applicable to dialogical writing. Based on empirical data from two university e-learning classes, we show how students use communicative routines in order to manage a specific (writing) task: During their group work students face the challenge of initiating new steps and mobilising other group members to proceed with the project. Our study shows that texts accomplishing this task usually follow a three-part structure: They give reasons why writing to the group becomes necessary ("account”), they request the start or continuation of working ("projection”) and they present a personal contribution to the task ("achievement/input”). In cooperative online work, appropriate dialogical writing is a crucial skill. This "dialogical text competence”, as we call it, cannot be taken for granted; indeed it must be taught and practiced as it differs from competences necessary in face-to-face interaction or for writing texts in non-dialogical contexts. We therefore close our paper with a discussion of our results under the aspect of learning and facilitating dialogical text competence in contexts that offer practical experience

Intricate Crosstalk Between Lipopolysaccharide, Phospholipid and Fatty Acid Metabolism in Escherichia coli Modulates Proteolysis of LpxC

Lipopolysaccharides (LPS) in the outer membrane of Gram-negative bacteria provide the first line of defense against antibiotics and other harmful compounds. LPS biosynthesis critically depends on LpxC catalyzing the first committed enzyme in this process. In Escherichia coli, the cellular concentration of LpxC is adjusted in a growth rate-dependent manner by the FtsH protease making sure that LPS biosynthesis is coordinated with the cellular demand. As a result, LpxC is stable in fast-growing cells and prone to degradation in slow-growing cells. One of the factors involved in this process is the alarmone guanosine tetraphosphate (ppGpp) but previous studies suggested the involvement of yet unknown factors in LpxC degradation. We established a quantitative proteomics approach aiming at the identification of proteins that are associated with LpxC and/or FtsH at high or low growth rates. The identification of known LpxC and FtsH interactors validated our approach. A number of proteins involved in fatty acid biosynthesis and degradation, including the central regulator FadR, were found in the LpxC and/or FtsH interactomes. Another protein associated with LpxC and FtsH was WaaH, a LPS-modifying enzyme. When overproduced, several members of the LpxC/FtsH interactomes were able to modulate LpxC proteolysis. Our results go beyond the previously established link between LPS and phospholipid biosynthesis and uncover a far-reaching network that controls LPS production by involving multiple enzymes in fatty acid metabolism, phospholipid biosynthesis and LPS modification

Serological immune response to cancer testis antigens in patients with pancreatic cancer

Serological screening approaches have allowed for the identification of a large number of potentially relevant tumor antigens in cancer patients. Within this group, cancer testis antigens represent promising targets for cancer immunotherapy, since they are widely expressed in a variety of human cancer entities. In pancreatic cancer, however, there are only few data available about the expression pattern and serological response to cancer testis antigens and other serological-defined tumor antigens. Therefore, we investigated the IgG antibody response against 11 cancer testis antigens (SCP-1, GAGE, LAGE-1a,-1b, CT-7, NY-ESO-1, SSX-1-5) recombinantly expressed on yeast surface (RAYS) in patients with pancreatic cancer (n = 96), chronic pancreatitis (n = 18) and healthy donors (n = 48). We found in 14% of all patients antibody responses to SCP-1, but not to other cancer testis antigens (GAGE, LAGE-1a,-1b, CT-7, NY-ESO-1, SSX-1-5). Antibody response correlated with the expression of SCP-1 in the primary tumor of the respective patient as shown by RT-PCR, immunohistochemistry and Western blot. In contrast, no serological response to cancer testis antigens was observed in healthy donors. The humoral immune response against SCP-1 was associated with the size of tumor, but not with other clinico-pathological parameters such as histology, stage, presence of lymph node metastases, grading, age, gender or gemcitabine treatment. In conclusion, antibody response to cancer testis antigen SCP-1 is found in a proportion of pancreatic carcinoma patients. These results indicate that identification of additional tumor antigens by serological screening of tumor cDNA expression libraries by RAYS is a promising goal in pancreatic cancer

Bone Marrow Plasma Cells Modulate Local Myeloid-Lineage Differentiation via IL-10

Bone marrow plasma cells have been reported to represent a major source of IL-10; however, the impact of plasma cell derived IL-10 in that tissue remains poorly understood. We confirm in this study that even in the absence of acute immune reactions, mature plasma cells represent the dominant IL-10+ cell population in the bone marrow, and identify myeloid-lineage cells as a main local target for plasma cell derived IL-10. Using Vert-X IL-10 transcriptional reporter mice, we found that more than 50% of all IL-10+ cells in bone marrow were CD138+ plasma cells, while other IL-10+ B lineage cells were nearly absent in this organ. Accordingly, IL-10 was found in the supernatants of short-term cultures of FACS-sorted bone marrow plasma cells, confirming IL-10 secretion from these cells. IL-10+ bone marrow plasma cells showed a B220−/CD19−/MHCII low phenotype suggesting that these cells represent a mature differentiation stage. Approximately 5% of bone marrow leucocytes expressed the IL-10 receptor (IL-10R), most of them being CD115+/Ly6C+/CD11c− monocytes. Compared to littermate controls, young B lineage specific IL-10 KO mice showed increased numbers of CD115+ cells but normal populations of other myeloid cell types in bone marrow. However, at 7 months of age B lineage specific IL-10 KO mice exhibited increased populations of CD115+ myeloid and CD11c+ dendritic cells (DCs), and showed reduced F4/80 expression in this tissue; hence, indicating that bone marrow plasma cells modulate the differentiation of local myeloid lineage cells via IL-10, and that this effect increases with age. The effects of B cell/plasma cell derived IL-10 on the differentiation of CD115+, CD11c+, and F4/80+ myeloid cells were confirmed in co-culture experiments. Together, these data support the idea that IL-10 production is not limited to early plasma cell stages in peripheral tissues but is also an important feature of mature plasma cells in the bone marrow. Moreover, we provide evidence that already under homeostatic conditions in the absence of acute immune reactions, bone marrow plasma cells represent a non-redundant source for IL-10 that modulates local myeloid lineage differentiation. This is particularly relevant in older individuals

Dialogische Textkompetenz – Routinisiertes Schreiben in studentischer Online-Teamarbeit

Current concepts in writing research primarily focus on monological texts, by which we mean texts that do not demand a reply. But nowadays, dialogical writing – the exchange of messages via e.g. e-mail, text message or internet forum – is increasingly prevalent in private, educational and professional life. We therefore argue that concepts of writing research should also be made applicable to dialogical writing. Based on empirical data from two university e-learning classes, we show how students use communicative routines in order to manage a specific (writing) task: During their group work students face the challenge of initiating new steps and mobilising other group members to proceed with the project. Our study shows that texts accomplishing this task usually follow a three-part structure: They give reasons why writing to the group becomes necessary (“account”), they request the start or continuation of working (“projection”) and they present a personal contribution to the task (“achievement/input”). In cooperative online work, appropriate dialogical writing is a crucial skill. This “dialogical text competence”, as we call it, cannot be taken for granted; indeed it must be taught and practiced as it differs from competences necessary in face-to-face interaction or for writing texts in non-dialogical contexts. We therefore close our paper with a discussion of our results under the aspect of learning and facilitating dialogical text competence in contexts that offer practical experience

Angst im Gespräch: eine gesprächsanalytische Studie zur kommunikativen Darstellung von Angst

Lindemann K. Angst im Gespräch: eine gesprächsanalytische Studie zur kommunikativen Darstellung von Angst. 1st ed. Göttingen: V&R Unipress; 2012